SlideShare a Scribd company logo

Arihant handbook biology for class 11 .pdf

•
•
C
chloefrazer622

Best handbook for neet

Education
1 of 654
Download to read offline
Sanjay Sharma ARIHANT PRAKASHAN, (SERIES) MEERUT handbook KEY NOTES TERMS DEFINITIONS FLOW CHARTS Highly Useful for Class XI & XII Students, Medical Entrances and Other Competitions Biology Supported by Kavita Agarwal Navraj Bharadwaj
© Publisher No part of this publication may be re-produced, stored in a retrieval system or distributed in any form or by any means, electronic, mechanical, photocopying, recording, scanning, web or otherwise without the written permission of the publisher. Arihant has obtained all the information in this book from the sources believed to be reliable and true. However, Arihant or its editors or authors or illustrators don’t take any responsibility for the absolute accuracy of any information published and the damages or loss suffered there upon. Head Office Kalindi, TP Nagar, Meerut (UP) - 250002 Tele: 0121-2401479, 2512970, 4004199; Fax: 0121-2401648 For further information about the books published by Arihant log on to www.arihantbooks.com or email to info@arihantbooks.com Regd. Office ‘Ramchhaya’4577/15, Agarwal Road, Darya Ganj, New Delhi -110002 Tele: 011- 47630600, 43518550; Fax: 011- 23280316 Administrative & Production Offices Agra, Ahmedabad, Bengaluru, Bareilly, Chennai, Delhi, Guwahati, Hyderabad, Jaipur, Jhansi, Kolkata, Lucknow, Meerut, Nagpur & Pune All disputes subject to Meerut (UP) jurisdiction only. Arihant Prakashan (Series), Meerut /arihantpub /@arihantpub Arihant Publications /arihantpub Sales & Support Offices ISBN : 978-93-13196-51-8 Published by Arihant Publications (India) Ltd. All Rights Reserved
Handbook means reference book listing brief facts on a subject. So, to facilitate the students in this we have released this Handbook of Biology. This book has been prepared to serve the special purpose of the students, to rectify any query or any concern point of a particular subject. This book will be of highly use whether students are looking for a quick revision before the board exams or just before other Medical Entrances. This handbook can even be used for revision of a subject in the time between two shift of the exams, even this handbook can be used while travelling to Examination Centre or whenever you have time, less sufficient or more. — To give confidence to the students just before they attempt important examinations. The objectives of publishing this handbook are : — To provide a focus to students to clear up their doubts about particular concepts which were not clear to them earlier. The format of this handbook has been developed particularly so that it can be carried around by the students conveniently. However, we have put our best efforts in preparing this book, but if any error or what so ever has been skipped out, we will by heart welcome your suggestions. Apart from all those who helped in the compilation of this book, a special note of thanks goes to Miss Akansha Tomar of Arihant Publications. — To support students in their revision of a subject just before an examination. Authors PREFACE
1. 1-6 The LivingWorld — CharacteristicsofLivingBeings — Taxonomy — Systematics — TaxonomicalAids — Biodiversity 2. 7-23 Biological Classification — Classification of Living Organisms — Kingdom–Protista — Biology : Nature and Scope — Kingdom–Fungi — Kingdom–Monera — Kingdom–Plantae — Kingdom–Animalia — Viruses andViroids CONTENTS 3. 24-42 4. 43-73 Plant Kingdom Animal Kingdom — Bryophyta — Pteridophyta — Angiospermae — Algae — Alternation of generations — Plants : Producers of Ecosystem — Gymnospermae — Phylum–Annelida — Phylum–Coelenterata(Cnidaria) — Phylum–Porifera — Phylum–Arthropoda — Phylum–Hemichordata — BasisofClassification — Phylum–Echinodermata — Phylum–Aschelminthes — Phylum–Chordata — Phylum–Mollusca — Phylum–Platyhelminthes 5. 74-103 Morphology of Flowering Plants — Seed — Flower — Fruit — Stem — Leaf — Inflorescence — Plant Morphology :An Overview 6. 104-121 Anatomy of Flowering Plants — Anatomy of Dicot and Monocot Plants — Secondary Growth in Plants — The tissues — Plant Tissue System
7. 122-151 Structural Organisation in Animals — Cockroach — EpithelialTissue(ByRuysch) — Tissue — NeuralTissue — ConnectiveTissue — MuscularTissue — Earthworm — Frog 8. 152-166 Cell : The Unit of Life — Components of a Cell — Cell — Cell Theory — Structure and Components of Eukaryotic Cell 9. 167-188 Biomolecules 10. 189-194 Cell Cycle and Cell Division — NucleicAcids — How to Analyse Chemical Composition? — DNA — Proteins — Lipids — Biomolecules — Carbohydrates(Saccharides) — Enzymes — RNA — Metabolites — Amitosis — CellCycle — SignificanceofCellCycle — DividingorM-phase 11. 195-206 Transport in Plants — Absorption of Water by Plants — Plant-Water Relation — Long Distance Transport of Water — Uptake and Transport of Mineral Nutrients — Upward Water Movement in a Plant — Translocation and Storage of Food in Plants (Phloem Transport) — Process Involved in Passive Transport 12. 207-214 Mineral Nutrition in Plants — Classification of Mineral Nutrients — Deficiency Symptoms of Essential Mineral Nutrients — Metabolism of Nitrogen — Hydroponics 13. 215-227 Photosynthesis in Higher Plants — Chemistry and Thermodynamics of Photosynthesis — Chloroplast : Photosynthetic Organ of Cell — Factors Affecting Photosynthesis — Photorespiration
14. 228-238 15. 239-248 Respiration in Plants Plant Growth and Development — Factors Affecting Respiration — Anaerobic Cellular Respiration — Cellular Respiration — Aerobic Respiration — Pentose Phosphate Pathway (PPP) — Plant Hormones/Phytohormones/ Plant Growth Regulators (PGRs) — Photoperiodism — Growth — Development — Seed Dormancy — Abscission of Plant Parts 16. 249-264 Digestion andAbsorption — DigestiveEnzymes — HumanDigestiveSystem — PhysiologyofDigestion — DisorderofDigestiveSystem — DigestiveGlands — DigestiveHormones — AlimentaryCanal 17. 265-275 Breathing and Exchange of Gases — RegulationofRespiration — ExchangeofGases — HumanRespiratorySystem — Respiration — Lungs — TransportofGases — DisordersofRespiratorySystem 18. 276-296 20. 307-329 19. 297-306 Body Fluids and Circulation Locomotion and Movement Excretory Products and Their Elimination — Body Fluids — Lymph — Blood — Circulatory System — BloodVascular System — Portal System — Human Circulatory System — Specialised Muscle Phenomena — Disorders of Muscular and Skeletal System — Movement — Muscle — Locomotion — Skeletal System — Joints — Micturition — Mechanism of Filtrate Concentration — Excretion — Human Excretory System — Excretory Products — Role of Other Organs in Excretion — Regulation of Kidney Function
21. 330-359 Neural Control and Coordination — Spinal Cord — Nerve Impulse — TheVisual Sense-The Eye — Human Ear-Organ of Hearing and Balance — Central Nervous System — Sense Organs — Reflex Arc — Brain — Reflex Action — Synapse — Human Neural System — BrainVentricles 22. 360-370 Chemical Coordination and Integration — Glands — Major Hormones of Human Endocrine System — Hormones — Mechanism of HormoneAction — Regulation of HormoneAction — Human Endocrine System 23. 371-375 Reproduction in Organisms — Reproduction in Plants — Reproduction in Animals — Events in Sexual Reproduction of Both Plants andAnimals 24. 376-390 Sexual Reproduction in Flowering Plants — Pollination — Fertilisation — Post-fertilisation Events — Flowers — Pre-fertilisation : Structures and Events — Development of Embryo/Embryogenesis 25. 391-414 Human Reproduction — Lactation — Embryonic Development — Male Reproductive System — Spermatogenesis — Structure of Sperm — The Menstrual Cycle — Foetal Development — Placenta — Female Reproductive System — Gametogenesis — Fertilisation — Implantation 26. 415-425 Reproductive Health — Sexually Transmitted Diseases — Assisted Reproductive Technology — Strategies to Improve Reproductive Health — Medical Termination of Pregnancy — Infertility — Detection of Foetal Disorders during Early Pregnancy — Acquired Immuno Deficiency Syndrome — Problems Related to Reproductive Health — Population Explosion
27. 426-449 Principles of Inheritance andVariation — Gregor Johann Mendel — Sex-Determination — Linkage — Mendel's Laws of Inheritance — Chromosomal Theory of Inheritance — Mutation — Pedigree Analysis — Heredity — Variations 28. 450-468 Molecular Basis of Inheritance — Human Genome Project — DNA Fingerprinting — Wobble Hypothesis — Regulation of Gene Expression — Genetic Code — RNA — Gene Expression — DNA — DNA as Genetic Material 29. 469-499 Evolution — Mechanism of Evolution — Mutation Theory — Origin of Life — Origin of Universe — Evidences of Evolution — Theories of Evolution — Darwinism — Human and Other Primates — Evolution of Human 30. 500-521 Human Health and Diseases — Adolescence — Autoimmunity — Drugs — Cancer — De-addiction — Acquired Immuno Deficiency Syndrome — Addiction — Complement System — Human Health — Common Diseases in Humans — Vaccination and Immunisation — Immunity and Immune System — Allergies 31. 522-537 Strategies for Enhancement in Food Production — LacCulture — AnimalHusbandry — PlantBreeding — SingleCellProtein — Apiculture/Bee-Farming — Improvement of Animals through Breeding — Pisciculture/FishFarming/Culture Fishery — Sericulture 32. 538-547 Microbes in Human Welfare — Microbes in Industrial Products — Biopesticides — Microbes in Household Products — Bioherbicides — Microbes in Sewage Treatment — Bioinsecticides
33. 548-561 Biotechnology : Principles and Processes — Genetic Engineering/Recombinant DNA Technology — Downstream Processing — Bioreactors — Principle of Biotechnology — Gel Electrophoresis — Tools of rDNA Technology 36. 586-603 35. 575-585 Ecosystem Organisms and Population — Ecosystem — Food Web — Features of Ecosystem — Ecosystem: Structure and Characteristics — Components of Ecosystem — Food Chain — Ecosystem Services — Population and Community — Organism and its Environment — Responses to Abiotic Factors — Adaptations — Characteristics of Population 34. 562-574 Biotechnology and ItsApplications — Applications of Biotechnology in Plant Tissue Culture — Applications of Biotechnology in Medicine — Types of Biotechnology — Applications of Biotechnology in Industry and Environment 37. 604-617 Biodiversity and Conservation — IUCN and Red List Categories — Levels of Biodiversity — Importance of Biodiversity — Biodiversity Conservation — Loss of Biodiversity — Patterns of Biodiversity 38. 618-639 Environmental Issues — Ozone Layer Depletion — Global Warming — Greenhouse Effect — Acid Rain — Degradation by Improper Resource Utilisation and Maintenance — Pollution Appendix 640-644
Life is a characteristic quality that differentiates inanimate (non-living) objects from the animate (living) forms. Characteristics of Living Beings 1 The Living World Metabolism Thermoregulation Cellular Organisation Composition and arrangement of ·cells in body. Process that allows your body to maintains its core internal temperature Reproduction Conciousness Adaptation Process of producing young ones by living things. Ability of an organism to sense its environment. Genetic mechanism of an organism to survive, thrive and reproduce by constantly enhancing itself. Heat Stroke Increase in body temperature above the normal level. Hypothermia Decrease in body temperature below the normal level. Multicellular Organisms Organisms with multiple cells of various type, , . e.g. Hydra Asexual Reproduction Does not involve the fusion of gametes or sex cells, e.g., Amoeba. Sexual Reproduction Involves the fusion of gametes, humans. e.g., Catabolism Process of breakdown of complex substances into simpler ones, respiration. e.g., Anabolism Process of formation of complex substances from simpler ones, photosynthesis. e.g., Short-term Adaptations Temporary changes to respond to changing environment, hibernation and aestivation. e.g., Long-term Adaptations Permanent changes in response to changing environment, humming birds. e.g., Irritability Ability of an organism to react against external stimuli, movement of an organism towards the light source. e.g., A series of chemical processes catalysed by enzymes, occurring within the body of living beings. Characteristics of Living Beings Unicellular Organisms Organisms having a single cell, , . e.g. Amoeba Growth Living organisms grow with increase in mass and number of individuals/cells.
Biodiversity It is the degree of variability among living organisms. It includes all the varieties of plants and animals. It encompasses all the ecological complexes (in which the diversity occurs), ecosystem, community diversity, species diversity and genetic diversity. It comprises all the millions of species and the genetic differences between them. Systematics It is the study of the biodiversity. It attempts to classify the diversity of organisms on the basis of following four fields viz, identification, classification, nomenclature. 1. Identification It aims to identify the correct name and position of an organism in the already established classification system. It is done with the help of keys. Key is a list of alternate characters found in organisms. An organism can be identified easily by selecting and eliminating the characters present in the key. 2. Classification It involves the scientific grouping of identified organisms into convenient categories or taxa based on some easily observable and fundamental characters. The various categories which show hierarchical arrangement in decreasing order are Kingdom → Phylum → Class → Order → Family → Genus → Species 3. Nomenclature After classification, organisms are subjected to a format of two-word naming system called binomial nomenclature. It consists of two components, i.e., generic name and specific epithet. For example, in Mangifera indica, ‘Mangifera’ is the generic name and ‘indica’ is the specific name of mango. This system was proposed by C Linnaeus (a Swedish Botanist) in (1753) in his book Species Plantarum. Polynomial system of nomenclature is a type of naming system containing more than two words. Trinomial system is a component of polynomial system and contains three words. Third word represents the sub-species and first two-words remain the same as in binomial system. Codes of Biological Nomenclature There are five codes of nomenclature which help to avoid errors, duplication and ambiguity in scientific names. 2 Handbook of Biology
The Living World 3 These codes are as follows ICBN International Code of Botanical Nomenclature ICZN International Code of Zoological Nomenclature ICVN International Code of Viral Nomenclature ICNB International Code for Nomenclature of Bacteria ICNCP International Code for Nomenclature for Cultivated Plants Types of Specification in Nomenclature The ICBN recognises following several types are given below Taxonomy It deals with the principles and procedures of identification, nomenclature and classification of organisms. It reflects the natural and phylogenetic relationships among organisms. It also provides the details of external and internal structures, cellular structure and ecological information of organisms. The term taxonomy was coined by AP de Candolle, 1813. Various Branches of Taxonomy Taxonomic Field Basis Alpha ( ) α Taxonomy Morphological traits Artificial Taxonomy Habit and habitat of organisms Natural Taxonomy Natural similarities among organisms Chemotaxonomy Presence or absence of chemicals in cells or tissues Cytotaxonomy Cytological studies Numerical or Phenetic Taxonomy Number of shared characters of various organisms Phylogenetic or Omega ( ) ω Taxonomy Based on phylogenetic relationships Neotype Holotype Lectotype Isotype Paratype Specimens described along with the holotype. New nomenclature type when the holotype is not available. Prototype specimen from which description of a new species is established. Specimen selected from original material when there is no holotype. It is the same as holotype. Syntype Any of the two or more specimens cited by an author when there is no holotype. Specification in Nomenclature
Classical Taxonomy It is also known as old taxonomy. In classical taxonomy, species is the basic unit and it can be described on the basis of one or few preserved specimens. Organisms are classified on the basis of some limited features. Modern Taxonomy/New Systematics The concept of modern taxonomy was given by Julian Huxley (1940). According to it, species are dynamic and ever-changing entity. Studies of organisms are done on a huge number of variations. It includes cytotaxonomy, numerical taxonomy, chemotaxonomy, etc. Taxonomic Categories Classification is not a single step process. It involves hierarchy of steps in which each step represents a rank or category. Since, the category is a part of overall taxonomic arrangement, it is called the taxonomic category. The taxonomic categories, which are always used in hierarchical classification of organisms are called obligate categories. The sub-categories like sub-species, sub-class, sub-family, etc., which facilitate more sound and scientific placement of various taxa are called intermediate categories. Arrangement of taxonomic categories in a descending order during the classification of an organism is called taxonomic hierarchy. It was first introduced by Linnaeus (1751) and hence, it is also known as Linnaean Hierarchy. 4 Handbook of Biology Taxonomic Categories For Plants For Animals Kingdom Kingdom Phylum Division Class Class Order Order Family Family Genus Genus Species Species Taxonomic categories showing hierarchical arrangement in ascending order
Taxon represents the rank of each category and referred to as a unit of classification. The term ‘Taxon’ was first introduced by ICBN during 1956. According to Mayr (1964), taxon is a group of any rank that is sufficiently distinct to be worthy of being assigned a definite category. In simple words, taxon refers to a group of similar, genetically related individuals having certain characters distinct from those of other groups. (i) Kingdom It is the highest category in taxonomy. A kingdom includes all the organisms which share a set of distinguished characters. (ii) Phylum or Division (Cuvier, Eichler) It is a taxonomic category higher than class and lower in rank to kingdom. The term ‘Phylum’ is used for animals, while ‘Division’ is commonly employed for plants. It consists of more than one classes having some similar correlated characters. (iii) Class (Linnaeus) It is a major category, which includes related orders. (iv) Order (Linnaeus) It is a group of one or more related families that possess some similar correlated characters, which are lesser in number as compared to a family or genera. (v) Family (John Ray) It is a group of related genera with less number of similarities as compared to genus and species. All the genera of a family have some common or correlated features. They are separable from genera of a related family by important differences in both vegetative and reproductive features. (vi) Genus (Term given by John Ray) It comprises a group of related species, which has more characters common in comparison to species of other genera. In other words, genera are the aggregates of closely related species. (vii) Species Taxonomic studies consider a group of individual organisms with fundamental similarities as a species (John Ray). It is the lowest or basic taxonomic category, which consists of one or more individuals of a population. The Living World 5
Taxonomical Aids They include techniques, procedures and stored information that are useful in identification and classification of organisms. Some of the taxonomical aids are as follows Importance of Taxonomical Aids l These aids help to store and preserve the information as well as the specimens. The collection of actual specimens of plant and animal species is essential and is the prime source of taxonomic studies. l These are also essential for training in systematics which is used for the classification of an organism. Hence, taxonomic aids facilitate identification, naming and classification of organisms using actual specimens collected from the fields and preserved as referrals in the form of herbaria, museums, etc. 6 Handbook of Biology Herbarium Storehouse of collected plant specimens that are dried, pressed and preserved on sheets. Manuals and Catalogues Provide information for identification of names of species found in an area. Museums Place for the collection of preserved plants and animal specimens. Monographs Contain information on any one taxon. Keys Used for identification of plants and animals based on their similarities and dissimilarities. Botanical and Zoological Parks Contain the living collection of plants and animals in the conditions similar to their natural habitat. Taxonomical Aids
2 Biological Classification Biology : Nature and Scope Biology (L. bios – life; logos – knowledge) is the branch of science, which deals with the study of living organisms and their life processes. Aristotle is called the Father of Biology, but the term ‘Biology’ was first coined by Lamarck and Treviranus in 1802. It has two main branches, i e . ., Botany (study of plants) and Zoology (study of animals). l Father of Botany Theophrastus l Father of Zoology Aristotle Classification of Living Organisms Classification is an arrangement of living organisms according to their common characteristics and placing the group within taxonomic hierarchy. The branch of science which deals with description, nomenclature, identification and classification of organisms is called taxonomy. Some major branches of taxonomy are (i) Numerical taxonomy It is based on all observable characteristics. Number and codes are assigned to characters and data is processed through computers. (ii) Cytotaxonomy In this taxonomy, the detailed cytological information is used to categorise organisms. (iii) Chemotaxonomy The chemical constituents are taken as the basis for classification of organisms.
On the basis of reference criteria, the classification of living organisms can be of three types 1. Artificial or Prior Classification In this system of classification one or very few characters are considered as the key feature of classification. This classification system never throws light on affinities or relationships between the organisms. 2. Natural or Phenetic Classification The classification system in which organisms are classified on the basis of their permanent vegetative characters. In this classification system, the grouping of heterogenous groups (unrelated) of organisms is avoided. 3. Cladistic or Phylogenetic Classification This classification may be monophyletic (i e . ., one ancestry), polyphyletic (i e . . the organism derived from two ancestors) and paraphyletic (i e . ., the organism does not include all the descendents of common ancestor). Cladistics is a method of classification of organisms based upon their genetic and ancestral relationships, which are more scientific and natural. The most accepted, five kingdom system of classification of living organisms was proposed by RH Whittaker. These five kingdoms are Monera, Protista, Fungi, Animalia and Plantae. Other Classification Systems l Two kingdom system–Carolus Linnaeus (Animalia and Plantae). Merits Photosynthetic organisms were included into plant kingdom and non-photosynthetic organisms were included into animal kingdom. Demerits Some organisms do not fall naturally either into plant or animal kingdom or share characteristics of both. l Three kingdom system–Ernst Haeckel (Protista, Animalia and Plantae). Merits Created a third kingdom which includes unicellular eukaryotic microorganisms and some multicellular organisms. Demerits Monerans were not placed correctly. 8 Handbook of Biology Artificial Prior Classification or Classification of Living Organisms Natural Phenetic Classification or Phylogenetic Cladistic Classification or
l Four kingdom system–Copeland (Monera, Protista, Animalia and Plantae). Merits Monerans were placed separately along with other kingdoms. Demerits Monerans were not subdivided in Archaebacteria and Eubacteria. l Six kingdom system–Carl Woese (Archaebacteria, Eubacteria, Protista, Fungi, Animalia and Plantae). Merits Archaebacteria and Eubacteria were separately placed. A. Kingdom–Monera (Prokaryotic, Unicellular Organisms) It includes all prokaryotes such as bacteria, archaebacteria, mycoplasma, actinomycetes, cyanobacteria and rickettsia. 1. Bacteria These unicellular, prokaryotic organisms contain cell wall (feature of plant cells only). These are approximately 4000 species of bacteria, with cosmopolitan occurrence. Bacteria can be regarded both friends and foes on the basis of interaction with human beings. An average weight human (~ 70 kg) has about 2.5 kg of bacteria in the form of gut microflora to supplement the proper digestion and other metabolic functions. Details to bacteria can be visualised in a nutshell as Biological Classification 9 Non-motile Bacteria On the basis of staining behaviour Cocci (rounded) On the basis of structure Bacilli (capsule) On the basis of nutrition Spirillum (spiral) Vibrio (comma-like) Methanogens Halophiles Eubacteria (true bacteria) Gram-Negative Bacteria Thermoacidophiles (methane producing bacteria) (salty/marine bacteria) (present in acidic sulphur springs) Archaebacteria Gram-Positive Bacteria Autotrophic Heterotrophic Photosynthetic bacteria Saprophytic Purple-sulphur bacteria Symbiotic Parasitic • • • • • Motile (primitive bacteria)
(i) Archaebacteria These are the group of most primitive prokaryotes. They have a cell wall, made up of protein and non-cellulosic polysaccharides. The presence of 16 srRNA, makes them unique and helps in placing in a separate domain called archaea between bacteria and eukarya. Archaebacteria can live under extreme hostile conditions like salt pans, salt marshes and hot sulphur springs. They are also known as living fossils, because they represent the earliest form of life on earth. Archaebacteria can be used for (a) Experimentation for absorption of solar radiation. (b) Production of gobar gas from dung and sewage. (c) Fermentation of cellulose in ruminants. (ii) Eubacteria Eubacteria are ‘true bacteria’ which lack nucleus and membrane bound organalles like mitochondria, chloroplasts, etc. Eubacteria are usually divided into five phylums– Spirochetes, Chlamydias, Gram- positive bacteria, Cyanobacteria and Proteobacteria. The structural detail of a typical eubacterial cell is given as follows 10 Handbook of Biology Capsule pathogens desiccation surface It is made up of gelatinous polysaccharide and polypeptide. It protects the bacteria, from and . It helps in adherance to any . Cytoplasm It contains 80% water, protein, carbohydrate, lipid, organic ions, etc. Ribosomes 70 S type of ribosomes, consists of RNA and proteins. r Cell Wall It is rigid due to the presence of murein. Cell wall contains Mg ions which bind to teichoic acid. This binding protects the bacteria from thermal injuries. 2+ Nuclear Area (Nucleoid) It is amorphous lobular mass of fibrillar chromatin type material which occupies 10-20% area of cell. Plasmid Small, circular, self-replicating extrachromosomal DNA, having few genes. Flagellum filament hook basal body Long, filamentous appendage consisting of , and . It is rotatory in function and contains flagellin protein. Inclusions glycogen starch lipid sulphur granules These are reserve food deposits found in prokaryotic and eukaryotic cells. These may be of , , and . Plasma Membrane Its structure and functions are similar to eukaryotic plasma membrane. It is also the site of some respiratory enzymes. Fimbriae pilin. These are short, filamentous structures composed of protein, These are evenly distributed and used for attachment rather than motility. Mesosome Complex localised infolding of membrane which serves as respiratory organ, ., centre of respiration. i.e Detailed structure of a bacterium
Nutrition in Bacteria The process of acquiring energy and nutrients., is called nutrition. On the basis of mode of nutrition, bacteria are of two types– autotrophic and heterotrophic. About 1% bacteria show autotrophic mode of nutrition and the rest are of heterotrophic habit. Chemosynthetic bacteria oxidise various inorganic substances such as nitrates, nitrites and ammonia and use the released energy for their ATP production. Autotrophic (i.e., photosynthetic) bacteria and heterotrophic bacteria with their related details are mentioned in following tables. Some Photosynthetic Bacteria Group Main Habitats Cell Wall Representatives Prochlorobacteria Live in tissues of marine invertebrates. Gram-negative Prochloron Purple or green bacteria Generally anaerobic and reside on sediments of lakes and ponds. Gram-negative Rhodospirillum and Chlorobium Some Heterotrophic Bacteria Group Main Habitats Cell Wall Representatives Spirochetes Aquatic habitats, parasites of animals Gram-negative Spirochaeta and Treponema. Aerobic rods and cocci Soil, aquatic habitats, parasites of animals and plants Gram-negative Pseudomonas, Neisseria, Nitrobacter, Azotobacter and Agrobacterium Facultative anaerobic rods (enterobacteria) Soil, plants, animal gut Gram-negative Salmonella, Shigella, Proteus, Escherichia and Photobacterium Sulphur and sulphate reducing bacteria Anaerobic muds, sediments (as in bogs, marshes) Gram-negative Desulfovibrio Myxobacteria Decaying plant and animal matter, bark of living trees Gram-negative Myxococcus and Chondromyces Biological Classification 11
Group Main Habitats Cell Wall Representatives Mycoplasmas Parasites of plants and animals Cell wall absent Mycoplasma Gram-positive cocci Soil, skin and mucous membranes of animals Gram-positive Staphylococcus and Streptococcus Endospore-forming rods and cocci Soil; animal gut Gram-positive Bacillus and Clostridium Non-sporulating rods Fermenting plant and animal material, human oral cavity, gut, vaginal tract Gram-positive Lactobacillus and Listeria Chemoautotrophes Soil, aquatic habitat Gram-negative Halothiobacillus and Acidothiobacillus Respiration in Bacteria Respiration occurs in the plasma membrane of bacteria. Glucose is broken down into carbon dioxide and water using oxygen in aerobic cellular respiration and other molecules such as nitrate (NO ) 3 in anaerobic cellular respiration. Reproduction in Bacteria Bacteria reproduce asexually and sexually both. Asexual Methods Asexually, bacteria reproduce by following methods l Fission Bacteria divide both laterally and longitudinally. l Budding Vegetative outgrowths result into new organisms after maturity. l Spore formation Non-motile spores like conidia, oidia and endospores are formed. Sexual Methods Although sexes are not differentiated in bacteria, following methods of genetic recombination are categorised under sexual reproduction in bacteria. l Transformation F Griffith (1928), Genetic material of one bacteria is transferred to other through conjugation tube. 12 Handbook of Biology
l Conjugation Lederberg and Tatum (1946), Transfer of genetic material occurs through sex pili. l Transduction Zinder and Lederberg (1952), Transfer of genetic material occurs by bacteriophage. Economic Importance of Bacteria Economically, some bacteria are useful in producing various useful substances like curd, cheese, antibiotics and vinegar, etc. While other bacteria cause several chronic diseases in humans, plants and other animals, etc. Other Monerans These are as follows 1. Mycoplasma l It was discovered by Nocard and Roux in 1898. These are cell wall less, aerobic and non-motile organisms. Due to the absence of cell wall and pleomorphic nature, they are commonly called as jokers of living world. l The mycoplasmas are also known as Pleuro Pneumonia Like Organisms (PPLO). These are the smallest living cells, yet discovered, can survive without oxygen and are typically about 0.1 µm in diameter. 2. Actinomycetes l The members of a heterogeneous group of Gram-positive, are generally anaerobic bacteria noted for a filamentous and branching growth pattern. It results in most forms in an extensive colony or mycelium. Biological Classification 13 Lipoprotein membrane (3 layers) Ribosomes DNA Soluble RNA Structure of Mycoplasma
l Morphologically, they resemble fungi because of their elongated cells that branch into filaments or hyphae. During the process of composting, mainly thermophilic and thermotolerent Actinomyces are responsible for the decomposition of the organic matter at elevated temperature. l Generally, Actinomycetes grow on fresh substrates more slowly than other bacteria and fungi. During the composting process, the Actinomycetes degrade natural substances such as chitin or cellulose. l Natural habitats of thermophilic Actinomycetes are silos, corn mills, air conditioning systems and closed stables. Some Actinomycetes are found responsible for allergic symptoms in the respiratory tract, e.g., Extrinsic Allergic Alveolitis (EAA). 3. Cyanobacteria/Blue-Green Algae (BGA) l They are Gram-negative photosynthetic prokaryotes which perform oxygenic photosynthesis. These can live in both freshwater and marine habitats and are responsible for ‘blooms’ in polluted water (eutrophication). l They have photosynthetic pigments, chlorophyll-a, carotenoids and phycobilins and food is stored in the form of cyanophycean starch, lipid globule and protein granules. l Cyanobacteria have cell wall formed of peptidoglycan, naked DNA, 70S ribosomes and the absence of membrane bound organelles like endoplasmic reticulum, mitochondria, Golgi bodies, etc. l The red sea is named after the colouration provided by red coloured cyanobacteria i.e., Trichodesmium erythraeum. l Cyanobacteria can fix atmospheric nitrogen through a specific structure called heterocyst. These are modified cells in which photosystem-II is absent hence, non-cyclic photophosphorylation does not take place. Nitrogen-fixation is performed through enzyme nitrogenase, present in it. 4. Rickettsia l These are small, aerobic and Gram-negative bacteria. They belong to phylum–Proteobacteria, which are capable of growing in low level of nutrients and have long generation time relative to other Gram-negative bacteria. l Rocky Mountain Spotted Fever (RMSF) is a tick borne human disease caused by Rickettsia rickettsii, an obligate, intracellular bacteria. 14 Handbook of Biology
B. Kingdom–Protista (Eukaryotic, Unicellular Organisms) It includes three broad groups, explained in the following flow chart In the view of evolution, the kingdom–Protista acts as a connecting link between the prokaryotic kingdom–Monera and multicellular kingdoms like Fungi, Plantae and Animalia. The term ‘Protista’ was given by German biologist, Ernst Haeckel in 1866. The group Protista shows following characteristics in common (i) These are mostly aquatic. (ii) Eukaryotic cell of protists possess well-defined nucleus. (iii) Membrane bound organelles present. (iv) Protists reproduce both asexually and sexually by a process involving cell fusion and zygote formation. (v) They may be autotrophic and heterotrophic (i.e., parasitic). The detailed descriptions of protistan groups are as follows Plant-like Protists (Photosynthetic) These can be 1. Dinoflagellates The group of 1000 species of photosynthetic protists, belongs to the division–Pyrophyta and class–Dinophyceae. They are unicellular, motile and biflagellate, golden-brown coloured protists. They form the important components of phytoplanktons. Their macronuclei possess condensed chromosomes, even in interphase, called as mesokaryon (Dodge; 1966). Sometimes they exhibit the phenomenon of bioluminescence. Biological Classification 15 Kingdom–Protista Animal-like Protists Euglenophyta (euglenoids flagellates) Ciliated Protozoans Fungi-like Protists Pyrophyta (dinoflagellates) Amoeboid Protozoans Acrasiomycota Plant-like Protists Myxomycota (acellular slime moulds) (cellular slime moulds) (photosynthetic protists) (slime moulds) (protozoans) Chrysophyta (diatoms) Flagellated Protozoans Subphyla Sporozoans Subphyla Subphyla @unacademyplusdiscounts
2. Chrysophytes These include diatoms and desmids. Diatoms are mostly aquatic and sometimes present in moist terrestrial habitat. They are very good pollution indicator. The diatoms do not decay easily as their body is covered by siliceous shell. They pile up at the bottom of water body and form diatomite or diatomaceous earth (can be used as fuel after mining). 3. Euglenoids These are Euglena like unicellular flagellates found mostly in stagnant freshwater. Instead of a cell wall, they have a protein rich layer called pellicle, which makes their body flexible. They have two types of flagella (i) Long Whiplash (ii) Short Tinsel The food is stored in proteinaceous granules called pyrenoids. Photosynthetic euglenoids, behave like heterotrophs in dark, this mode of nutrition is called mixotrophic. The chief member of this group, i.e., Euglena is regarded as connecting link between animals and plants. Fungi-Like Protists (Slime Moulds) They possess the characters of both animals and fungi therefore, combinedly called as fungus-animals. They show saprophytic food habit and consume organic matter. Under suitable conditions, they form Plasmodium. On the basis of occurrence of Plasmodium, these are of two types (i) Acellular/Plasmodial slime moulds, e.g., Physarum, Fuligo septica, etc. (ii) Cellular slime moulds, e.g., Dictyostelium, Polysphondylium,etc. Animal-Like Protists (Protozoans) The most primitive relatives of animals, protozoans are heterotrophic (predator or parasitic) organisms, divided into four major groups (i) Amoeboid protozoans They live in freshwater, moist soil and salt water as parasite. They move with the help of pseudopodia as in Amoeba. Other members of this group are Entamoeba histolytica and E. gingivalis cause various digestive and oral diseases when engulfed through polluted water. 16 Handbook of Biology
(ii) Flagellated protozoans They are either free-living or parasitic in nature. Chief members are (a) Trypanosoma sp.–carried by tse-tse fly and causes African sleeping sickness. (b) Leishmania sp. carried by sand fly and causes kala-azar or dum-dum fever. (c) Giardia sp. causes giardiasis. (d) Trichomonas vaginalis causes leucorrhoea. (iii) Ciliated protozoans They are aquatic and move actively due to the presence of cilia. They show nuclear dimorphism (macro and micronucleus), e.g., Paramecium, etc. (a) Macronucleus/Vegetative nucleus Controls metabolic activities and growth. (b) Micronucleus/ReproductivenucleusControls reproduction. (iv) Sporozoans They have an infectious, spore-like stage in their life cycle. All are endoparasites. Locomotory organs are cilia, flagella and pseudopodia, e.g., Plasmodium, Monocystis, etc. C. Kingdom–Fungi (Eukaryotic, Heterotrophic Organisms) Fungi are a group of eukaryotic, achlorophyllous, non-photosynthetic and heterotrophic organisms. The basic features of fungi include (i) Fungi lack chlorophyll, hence they are heterotrophic. (ii) They cannot ingest solid food, but absorb it after digestion. The digestive enzymes are secreted on food, then they (fungi) absorb it. (iii) On the basis of food sources, they may be saprophyte or parasites. Cell wall in fungi is made up of nitrogen containing polysaccharides, chitin. Reserved food material is glycogen or oil. Along with certain bacteria, saprotrophic fungi function as the main decomposers of organic remains. With the exception of yeasts (unicellular, fungi and filamentous), fungi bodies consist of long, slender, thread-like structures called hyphae. Mycelium is the network of hyphae. Some are called coenocytic hyphae (continuous tubes filled with multinucleated cytoplasm) and others have cross walls (septae) in their hyphae. Cell walls of fungi are composed of chitin and polysaccharides. Biological Classification 17
Classification of Fungi (Martin; 1961) Reproduction in Fungi Three types of reproduction occur in fungi 18 Handbook of Biology Reproduction Vegetative Asexual Sexual Fragmentation Zoospore Conidia Planogametic copulation Budding Sporangiospore (Phycomycetes) Ascospore (Ascomycetes) Gametangial contact Fission Chlamydospore Basidiospore (Basidiomycetes) Gametangial copulation Sclerotia Oidia Binucleate spore Spermatogamy Rhizomorphs Somatogamy When a vegetative structure after separation produces new individual, it is called vegetative reproduction. It occurs by following processes During asexual reproduction, several mononucleate and binucleate spores are produced which later germinate into new individuals. It occurs by following methods In sexual reproduction, the fusion of compatible nuclei takes place. It involves three steps, plasmogamy, karyogamy and meiosis. It occurs by following methods Fungi Myxomycetes (body as amoeboid naked protoplast) Eumycetes (unicellular, multicellular, filamentous) Phycomycetes (mycelium aseptate and multinucleate) Ascomycetes (mycelium septate) Deuteromycetes (mycelium septate) Basidiomycetes (septate) e.g., Allomyces Puccinia and , etc. l l Members are found in aquatic habitats; decaying wood in damp places. Reproduce asexually by zoospores or aplanospores. l l l Known as sac fungi, mostly multicellular ( ) or rarely unicellular (yeast). Asexual spores are conidia produced on conidiophores. Sexual spores are ascospores produced on asci. Penicillium e.g., Albugo, etc. l l Known as imperfect fungi. Deuteromycetes reproduce only by asexual spores, conidia. e.g., , , etc. Synchytrium Aspergillus e.g.,Agaricus, etc l l Grow in soil, on logs and in living plant bodies. Reproduce vegetatively by fragmentation, sex organs are absent.
Life Cycles of Some Fungi These can be described as follows (i) Life Cycle of Rhizopus The structural representation (sexual and asexual) of life cycle of Rhizopus is as follows Biological Classification 19 Vegetative Reproduction Fragmentation Oidia Sporangium Azygospore Meiosis Rhizopus mycelia Germ spores (+ or –) Germ sporangium Promycelium Fertilisation Diplophase (2 ) n Zygospore Haplophase ( ) n Gametangium Progametangium Progametangium(–) Sexual Reproduction Gametangium (–) Coenogamete (–) (+) + Chlamydospore Asexual Reproduction Coenogamete (+) Life cycle of Rhizopus
(ii) Life Cycle of Yeast The diagrammatic representation of sexual cycle of Saccharomyces cerevisiae is as follows Heterothallism The phenomenon of having two genetically different and compatible sexual strains in two different thalli is called heterothallism. It was discovered by Blakeslee in Mucor. 20 Handbook of Biology Budding Gametangia Plasmogamy Ascospore Ascospores Germinate Mature ascus Young ascus Meiosis Ascus mother cell Large strain yeast cell Budding Bud Germination Zygote Karyogamy H a p l o p h a s e D i p l o p h a s e Dwarf strain yeast cells ( n ) ( 2 n ) D E F G H J K L A B C + + – – I Life cycle of Saccharomyces cerevisiae
Mushroom and Fairy Rings Agaricus compestris is an edible mushroom. It is also called white button mushroom. The fruiting body of Agaricus, arises in concentric rings (called fairy rings or fungal flowers) from the mycelium present in the soil. Lichens They have composite structure and consist of two dissimilar organisms forming a symbiotic relationship between them. Lichens are formed by l Algal Part — Phycobiont — Provide food to fungi l Fungal part — Mycobiont — Provide shelter to algae Lichens are of three types on the basis of their structure (i) Crustose lichens These are point-like, flat lichens, e.g., Caloplaca. (ii) Foliose lichens These lichens have leafy structure, e.g., Hypogymnia physodes. (iii) Fruticose lichens These are branched lichen, form filamentous branching, e.g., Cladonia evansii, Usnea australis, etc. Various forms of lichens are given below Mycorrhiza It is a symbiotic association between a fungus and a plant. Plants prepare organic food and supply them to fungus and in return, fungus supplies water and mineral nutrients to plants. Biological Classification 21 Cora (foliose) Parmella (foliose) Cladonia (fruticose) Graphis (crustose) Attaching disc Fungal fructification Pendent branches Fungal fructification Usnea (fruticose) Podetia Early foliose part Forms of lichens
D. Kingdom–Plantae (Eukaryotic, Chlorophyllous Organisms) These are chlorophyllous and embryo forming organisms. Mostly non-motile and function as the producers in ecosystem as they can fix solar energy into chemical energy through the process of photosynthesis. The cell wall in plants is cellulosic and stored food material is in the form of starch. A detailed account of plant kingdom is given in chapter 6. E. Kingdom–Animalia (Multicellular, Eukaryotic Organisms) The heterotrophic, eukaryotic organisms which are multicellular and lack cell wall, present in this kingdom. Animals have advanced level of tissue organisation, in which the division of labour is highly specific. The two main groups among animals are Non-chordata and Chordata, divided on the basis of the presence of notochord in them. A detailed account of animal kingdom is given in chapter 7. Viruses and Viroids 1. Viruses The term ‘Virus’ means poisonous fluid. The word was coined by Louis Pasteur. Viruses are very small (0.05-0.2 µm), infective, nucleoprotein particles, which can be called as living because of the presence of nucleic acid as genetic material and ability to produce their own copy-viruses. They show only some properties of living beings, otherwise they behave like non-livings. Hence, these are referred to as the connecting link between living and non-living. On the basis of nature of genetic material, the viruses are of two types (i) Adenovirus DNA containing, e.g., HIV, etc. (ii) Retrovirus RNA containing, e.g., Rous sarcoma virus, etc. On the basis of their host, the viruses can be categorised as (i) Animal virus (Zoophagineae), e.g., HIV, sarcoma, etc. (ii) Plant virus (Phytophagineae), e.g., TMV, etc. (iii) Bacterial viruses (Phagineae), e.g., T4 phage, etc. Characteristics of Viruses Characteristics of viruses are as follows Living l They can replicate. l In host body, they can synthesise protein. l They cause diseases like other living organisms. l Similar gene mutation as living organism. 22 Handbook of Biology
Non-living l Do not have protoplasm, and do not perform metabolism. l These can be crystallised. l They do not respire. l In vitro culture is not possible. Structure of Viruses (i) Viruses are non-cellular and ultramicroscopic. (ii) Virus has two components (a) A core of nucleic acid called nucleoid. (b) A protein coat called capsid. 2. Viroids (RNA without a Capsid) TO Diener (1917) introduced the term as ‘Subviral pathogens’. Viroids are 100 times smaller than smallest virus. They are known to be infectious for plants only (no animal), e.g., potato spindle tuber caused by viroids. Virion An intact, inert, complete virus particle capable of infecting the host lying outside the host cell in cell free environment is called virion. Virusoids These are like viroids, but located inside the protein coat of a true virus. Virusoid RNA can be circular or linear. These are non-infectious as they are replicated only in their host. Prions/Slow Virus The prions are smallest, proteinaceous infectious particles, i.e., disease causing agents that can be transmitted from one animal to another. Biological Classification 23 Genetic material, DNA or RNA Core region inside capsid Capsomeres, together form capsid, a protein coat usually highly symmetrical. Envelope, only in some larger viruses. Structure of a virus (generalised)
3 Plant Kingdom Plants : Producers of the Ecosystem Plants are multicellular, photoautotrophic and embryo forming (excluding algae) organisms placed in kingdom–Plantae. They have cell wall, which is made up of cellulose and reserve food material in the form of starch (sometimes fat as in seeds). Plants are referred to as producers, because they have unique ability to fix solar energy in the form of chemical energy, through the process of photosynthesis. They supply the energy in ecosystem to other living organisms, hence they are referred to as producers. The plant kingdom is classified as Algae (L. Alga–sea weeds) These are eukaryotic, autotrophic (holophytic), chlorophyll containing, non-vascular thallophytes. These are characterised by the absence of embryonic stage and presence of non-jacketed gametangia. Mostly, they are of aquatic habitat (both freshwater and marine). The branch of Botany which deals with the study of algae is termed as ‘Algology or Phycology’. FE Fritsch is known as ‘Father of Algology’. (Prof. MOP Iyengar is regarded as Father of Indian Algology). Angiosperms (covered seed) Dicotyledons Gymnosperms (naked seeded plants) Monocotyledons Plant Kingdom Cryptogamae (non-flowering) Phanerogamae (flowering) Algae Thallophyta Bryophyta (these are embryophytes without vascular tissues.) Pteridophyta (these are embryo bearing plants which form seed and contain vascular tissue as well.) Liverworts Hornworts Mosses Ferns (non-embryophytes, lack seeds and vascular tissue.) (plant body is not divided into root, stem and leaves)
Classification of Algae (FE Fritsch; 1935) Algal Class Colour Reserve Food Examples Chlorophyceae Grass green Starch Chlamydomonas and Spirogyra. Xanthophyceae Yellow-green Fat Microspora and Botrydium. Chrysophyceae Yellow-green and golden-brown Carbohydrate and leucosin Amphipleura and Chrysosphaera. Bacillariophyceae Brown and green Fat and volutin Pinnularia and Melosira. Cryptophyceae Red and green-blue Carbohydrate and starch Cryptomonas. Dinophyceae Dark yellow, brown-red Starch and oil Peridinium and Glenodinium. Chloromonadineae Bright green Fatty compounds Vaucheria and Trentonia. Euglenophyceae Grass green Paramylum Euglena and Phacus. Phaeophyceae Brown coloured Laminarin and mannitol Laminaria and Fucus. Rhodophyceae Red coloured Floridean starch Polysiphonia and Batrachospermum. Myxophyceae Blue-green Protein granules Nostoc and Anabaena. Characteristics of Algae Important characteristics of algae are given below Structure Algae may be unicellular and multicellular. 1. Unicellular It is of two types (i) Motile, e.g., Chlamydomonas, etc. (ii) Non-motile, e.g., Chlorella, etc. 2. Multicellular It is of following types (i) Colonial, e.g., Volvox, Hydrodictyon, etc. (ii) Aggregation, e.g., Tetraspora, Prasinocladus, etc. (iii) Filamentous, e.g., Ulothrix, Cladophora, etc. (iv) Pseudoparenchymatous, e.g., Nemalion, etc. (v) Siphonous, e.g., Vaucheria, etc. (vi) Parenchymatous, e.g., Ulva, Fritschiella, etc. (vii) Well-developed thallus, e.g., Chara, Sargassum, etc. Plant Kingdom 25
Nutrition Mostly algae are autotrophic, due to the presence of chlorophyll. Some are parasitic, e.g., Cephaleuros that causes rust of tea. Reproduction Algae reproduce by (i) Vegetative methods (ii) Asexual methods (iii) Sexual methods Vegetative Reproduction Algae reproduce vegetatively by two methods (i) Fragmentation, e.g., Fucus, Chara, etc. (ii) By hormogones, e.g., Oscillatoria, Nostoc, etc. Asexual Reproduction In this process, some cells form motile or non-motile spores. After release, these spores give rise to new plants. Following spores are involved (i) By zoospore, e.g., Ulothrix, Oedogonium, etc. (ii) By aplanospore, e.g., Chlorella, etc. (iii) By hypnospore, e.g., Vaucheria, etc. (iv) By palmella stage, e.g., Chlamydomonas, Ulothrix, etc. (v) By endospore, e.g., Anabaena, Nostoc, etc. (vi) By akinete, e.g., Chara, Oedogonium, etc. Sexual Reproduction On the basis of shape, size, morphology and behaviour of gametes, the sexual reproduction is of following types 26 Handbook of Biology Isogamous (similar gametes, morphologically), e.g., Spirogyra. Anisogamous (gametes are dissimilar morphologically), sp. e.g., Chlamydomonas Oogamous (gametes are different both morphologically and physiologically), e.g.,Volvox. Sexual Reproduction
Life Cycle of Algae Various algae show different types of life cycles. Life cycles of Spirogyra and Ulothrix are discussed here. Life cycle of Spirogyra It is a green alga of filamentous shape. The detailed life cycle is given below. Plant Kingdom 27 Aplanospore Azygospore Akinete Asexual reproduction Pyrenoids Cell wall Vegetative cell Vegetative filament Three degenerating nuclei Functional nucleus Sexual reproduction Haploid phase ( ) n Four haploid nuclei ( M e i o s i s ) Diploid phase (2 ) n Male gamete ( ) n Conjugation tube Female gamete ( ) n Zygospore (2 ) n Zygote (2 ) n S c a l a r i f o r m c o n j u g a t i o n 11 10 9 8 7 6 5 4 3 2 1 Chloroplast Cytoplasm Nucleus Life cycle of Spirogyra
Life cycle of Ulothrix The diagrammatic representation of life cycle of Ulothrix is given below. 28 Handbook of Biology Palmella stage Akinete Hypnospore Macrozoospores Microzoospore Aplanospore Asexual reproduction Chloroplast Nucleus Vacuole Vegetative cell Gametangium Isogametes Vesicle Syngamy Quariflagellate zygospore Vegetative filament Sexual reproduction Haploid phase ( ) n 1 2 3 4 5 6 7 8 9 + – 10 11 12 Reduction division Resting 13 Zygospore (2 ) Phase (2 ) n n 14 15 Hold fast Zoospores Liberations of gametes Life cycle of Ulothrix
Economic Importance Algae can be both useful and harmful. Several useful algal species with their uses are mentioned here Algin, Carrageenan and Agar l Algin, used as artificial fibre to control blood flow in surgery and in production of non-inflammable films, is extracted from marine brown algae. l Carrageenan, extracted from seaweeds is used in cosmetics, boot polish, ice cream, paints, etc. l Agar, extracted from Gelidium and Gracilaria is used in culture medium, biscuits for diabetic patients, etc. – Sargassum is used as food and fodder. – Laminaria, Fucus are used in extraction of iodine, bromine and potash. Harmful Algae Group of algae like Microcystis, Oscillatoria and Anabaena cause water blooms (eutrophication) and death and reduction of aquatic organisms. Bryophyta (L. Bryon–leaf-like; phyton–plant body) It is the simplest and primitive group of land plants. They are also known as amphibians of plant kingdom because of their habitat adaptability in both aquatic and terrestrial environment. They are the connecting link between algae and pteridophytes. Bryophytes Plant Kingdom 29 As Medicine As Food Ulva, Sargassum, Laminaria, Porphyra, Nostoc Laurencia. and Chlorella Nitella gives chlorellin (antibiotic), is used as mosquito repellent. In Industries Diatoms, are used in paints, cosmetics, etc. Chondrus, Polysiphonia, Gracilaria Source of Minerals Laminaria, Polysiphonia Ascophyllum and are used in extraction of minerals. In Agriculture Nostoc, Anabaena, help in nitrogen-fixation, hence used as biofertilisers. In Biological Research Algae like planktons are used as food by others and stabilise the ecosystem. Chlorella,Scenedesmus Acetabularia and are used as tools for biological research. Ecological Significance Algae Useful applications of algae
are autotrophic, non-seeded, cryptogamic plants. The plant body is gametophytic and may be differentiated into stem, leaves and rhizoids. l Bryophytes do not have true vascular tissue (xylem and phloem), but some of them have hydroids (similar to xylem) and leptoids (similar to phloem) which help in the conduction of water and food, respectively. l The sex organs in bryophytes are multicellular, male sex organ is called antheridium and female sex organ is called archegonium. Sexual reproduction in bryophytes is mainly oogamous type. Classification of Bryophyta Reproduction in Bryophytes Bryophytes reproduce by both vegetative and sexual methods of reproduction. Vegetative Reproduction Following methods of vegetative reproduction are reported in bryophytes (i) By fragmentation The two fragments resulted by progressive death and decay of thallus, produce new thallus, e.g., Riccia. 30 Handbook of Biology Sphaerocarpales e.g.,Sphaerocarpus. Jungermaniales e.g., Porella Calobryales e.g., Calobryum. Bryophyta (sub-division) Hepaticopsida (Liverworts) Anthocerotopsida (Hornworts) Bryopsida (Mosses) Bryales e.g., Funaria Polytrichum. and Sphagnales e.g.,Sphagnum. Classes Orders Marchantiales e.g., Marchantia Riccia. and Order Anthocerotales , e.g. Anthoceros Orders l l l Plant body is thalloid or foliose. Cells have chloroplast without pyrenoids. Sporophyte simple or differentiated into foot, seta and capsule. l l l Plant body is thalloid and dorsiventrally flattened. Sex organs embedded in the thallus tissue. Cells bear large chloroplast with a conspicuous pyrenoid. l l l Primary gametophyte consists of prostate or thalloid protonema. Adult gametophyte consists of stem, spirally arranged leaves. Sex organs develop from superficial cells.
(ii) By adventitious branches Special adventitious branches arise from the mid-ventral surface of the thallus, e.g., Riccia fluitans. (iii) By tubers Some species form perennating tubers at the apices of thallus, e.g., Riccia, Marchantia, etc. (iv) By persistent apices The underground part of thallus in soil remains living and grows into plant, e.g., Riccia, Pellia, etc. Sexual Reproduction The sex organs are highly differentiated and well-developed in bryophytes. The antherozoids or sperms (minute, slender, curved body, having two whiplash flagella) are released from antheridium and reach to archegonium through neck canal cells. The antherozoid fuses with egg cell to produce sporophytic generation. Life Cycle of Bryophytes A typical bryophyte shows following type of life cycle Plant Kingdom 31 Vegetative reproduction ( ) n Bryophyte Protonema ( ) n ( ) n Sexual Reproduction Female ( ) n Male ( ) n Spores ( ) n Meiosis (R/D) Spore mother cell (2 ) n Antheridium ( ) n Archegonium ( ) n Antherozoid ( ) n Egg ( ) n Fertilisation (syngamy) Zygote (2 ) n Embryo (2 ) n Sporogonium (2 ) n Gametophyte ( ) n Sporophyte (2 ) n Graphic representation of the life cycle of bryophyte (R/D refers to reductional division)
Economic Importance Bryophytes have limited economic importance, they can be used in following ways (i) They help in soil formation (pedogenesis) and act as agent for biological succession. (ii) Peat from Sphagnum can be used as fuel and in preparation of ethyl alcohol. (iii) They help in protecting soil from erosion. (iv) Some bryophytes are used as fodder for cattle. (v) Due to high water retention capacity, Sphagnum can be used in preserving living materials and used in grafting of plants. Pteridophyta ( L. pteron–feather; phyton–plant) Pteridophytes are seedless, vascular cryptogams. They reproduce by means of spores and can reach to the tree-like heights (30-40 feets). General Characteristics (i) The plant body is differentiated into root, stem and leaves. (ii) The stem may be aerial or underground and is generally herbaceous, rarely solid and stout. (iii) Vascular tissues consist of xylem (without vessels) and phloem (without companion cells). (iv) Alternation of generations is found here, gametophyte is autotrophic and independent. (v) Sporangia containing leaves are called sporophylls. (vi) Antherozoids (flagellated male gametes) are formed in antheridia. (vii) Reproduction is of both vegetative and sexual types. (viii) On the basis of development of sporangia, they are of two types (a) Eusporangiate From a group of superficial initial cells. (b) Leptosporangiate From a single superficial initial cell. 32 Handbook of Biology
Stelar System in Pteridophytes Stele is central vascular tissue surrounded by cortex. It is of two types Classification of Pteridophyta (Smith; 1955, Bold; 1955-57, Benson; 1957) Plant Kingdom 33 Division–Pteridophyta Psilophyta Lycophyta or Lepidophyta Sphenophyta or Arthrophyta Filicophyta or Pterophyta (foliage leaves are borne in transverse whorls, horse tails). e.g., (differentiated sporophytes contain strobili). (sporophyll contains sori ferns). e.g., (rootless sporophytes). Sub-division Endodermis Leaf trace Pericycle Phloem Xylem Leaf gap Pith Endodermis Pericycle Phloem Xylem Haplostele Outer endodermis Outer pericycle Outer phloem Inner pericycle Xylem Inner endodermis Leaf trace Leaf gap Xylem Phloem Pericycle Endodermis Actinostele Leaf trace Xylem Phloem Endodermis Pith Endodermis Pericycle Phloem Xylem Leaf trace Xylem in centre is surrounded by phlem e.g., Selaginella. Xylem Phloem surrounds the central pith. is outside to xylem, e.g., Pteridium. Central xylem core surrounded by phloem e.g., Rhynia Central xylem core is star-shaped phloem is patchy outer to xylem, ., e.g Lycopodium. Ectophloic Solenostele Xylem is like hollow cylinder surrounded by phloem e.g., Equisetum Amphiphloic Solenostele Hollow xylem cylinder has phloem on both outer and inner side of xylem, e.g., Marsilea Protostele Siphonostele
Reproduction Pteridophytes reproduce by vegetative, asexual and sexual methods. Vegetative Reproduction It takes place by two methods (i) Death and decay of older tissues lead to separation of new branches, which can grow into new plants. (ii) Adventitious buds develop from petiole and later on rooting takes place and get separated. Asexual Reproduction It occurs by meiospores When pteridophytic plants get mature, the special spore bearing structures develop under the surface of pinnules. These structures are (i) Sporangium These are differentiated into capsule and the stalk. Capsule has a single layer of thick wall, which consists of specialised cell along with the normal wall cells. (ii) Spores These are minute, bilateral bodies of brown colour. The spore coat is two layered, i.e., thick exine and thin intine. Sexual Reproduction It is of advanced type, in which the multicellular sex organs (i.e., antheridia and archegonia) are borne on the underside of prothallus. The mucilaginous substance oozes out from archegonia, which contains malic acid. After diffusing into water, it attracts antherozoids through chemotaxis. The male nucleus fuses with the egg nucleus and forms zygote. 34 Handbook of Biology
Life Cycle of Pteridophytes Most pteridophytic plants show similar type of life cycle. Which is diagrammatically represented below. Heterospory in Pteridophytes In heterosporous plants, a sporophyte produces two types of sporangia–micro and megasporangia. Microsporangia contain Microspore Mother Cell (MMC) each of which undergoes meiosis and produces microspores. Megasporangia contain megaspore mother cell, which after going through meiosis, produces megaspores. Microspore Microgametophyte germinate (possess an → theridia) Megaspore Megagametophyte germinate (possess arch → egonia) Plant Kingdom 35 Circinate leaf Sori Leaflet Roots with diarch condition of xylem Lower epidermis Sporangia (stalked) Upper epidermis Rhizoids Apicol Notch Germinating spore Apical notch Archegonium Antheridia Rhizoids Prothallus with archegonia and antheridia Egg Neck Archegonium A single antherozoids Cilia Antherozoids Antheridia Rhizoids Prothallus with autotrophic nutrition First leaf Cushion 2n n G am etophytic phase Sporophytic plant Sporophytic phase Rhizome with mesarch xylem Sporangium Stomium Spores Part of sporophyll with sori Covering by indusium Stalk Strobilus Mesophyll Placenta Life cycle of Dryopteris
The differentiation between male and female gametophytes ensures cross fertilisation. This set of conditions occurs in Marsiliaceae and Salviniaceae. Economic Importance Pteridophytes are economically important group of plants. Some of them are (i) Pteridophytes are used in horticulture, since they resist wilting so can be used in cut flower arrangements. (ii) Some ferns are used in handicrafts and basketery. (iii) Pteridium leaves are used in making green dyes. (iv) Club mosses are used for making industrial lubricant since their spores contain non-volatile oils. These spores are also used as fingerprint powder in forensic investigation. (v) Some pteridophytes are used as biofertiliser (Azolla) due to their nitrogen-fixing ability. (vi) Some pteridophytes are eaten as food. Gymnospermae (L. gymnos – naked; sperma – seed) Gymnosperms are naked seeded plants, which evolved earlier than the flowering plants. They have their seeds exposed on the megasporophylls, i.e., carpels. Probably, they are the first surviving seed plants (evolved during Jurassic period). General Characteristics (i) Plants are sporophytic, differentiated into root, stem and leaves. (ii) Always heterosporous, i.e., contains two types of spores (one spore (microspore) produces male gametophyte and other (megaspore) produces female gametophyte after germination). (iii) Root system is well-developed, i.e., tap root system, some have coralloid roots (e.g., Cycas). (iv) Form various structures through symbiotic relationships, i.e., coralloid root (with algae) and mycorrhizae (with fungi). (v) Leaves are dimorphic. They are of two types (a) Foliage leaves Green, simple, needle-shaped and pinnately compound. (b) Scaly leaves Minute and deciduous. (vi) Flowers are unisexual, simple, reduced and naked, i.e., without perianth (except Gnetum). 36 Handbook of Biology
Classification of Gymnospermae Classification of gymnosperms was described by A Arnold (1948) and modified by Pilger and Melchior (1954). Reproduction Gymnosperms reproduce by both vegetative and sexual methods. Vegetative Reproduction This is done by bulbils, which commonly arise on trunk. These bulbils get separated from plants and germinate into new plants. Sexual Reproduction The life cycle of gymnosperms is also characterised by alternation of generations. The green leafy part of the plant is the sporophyte while, the cones contain the male and female gametophytes. Upon landing on the female cone, the tube cell of the pollen forms the pollen tube, through which the generative cells migrate towards the female gametophyte. The generative cells split into two sperm nuclei, one of which fuses with the egg, while the other degenerates. After fertilisation of the egg, the diploid zygote is formed, which divides by mitosis to form embryo. The seed is covered by a seed coat, which is derived from the female sporophyte. No fruit formation takes place as gymnosperms do not have true seed covering. Life Cycle of Gymnosperms The gymnosperms are higher plants with advanced life cycle. Plant Kingdom 37 Division–Gymnospermae Cycadopsida [monoxylic wood, large frond (a type of leaf) and bipinnately compound leaves] and e.g., Cycas Zamia. Coniferopsida (large tree of sporophytic nature, produce cones in reproductive phase) and e.g., Pinus Cordaites. Gnetopsida (include both extinct and extant genera) and e.g., Gnetum Ephedra.
38 Handbook of Biology The descriptive account of life cycle of both Cycas and Pinus are as follows Life Cycle of Cycas Life Cycle of Pinus Male plant Staminate cone Microsporophyll Microsporangium (pollen sac) Microspore mother cell Microspore (pollen grain) Microgametophyte Body cell Male gamete (antherozoid) Oospore (zygote) Development of embryo Seed Female plant Megasporophyll Megasporangium (ovule) Megaspore mother cell Megaspore Megagametophyte (endosperm) Archegonium Female gamete (oosphere) Sporophyte (2 ) n Syngamy Gametophyte ( ) n Meiosis G erm ination Germination Cycas : Topographical representation of life cycle Female strobilus Megasporophylls Megasporangia (ovules) Megaspore mother cells Meiosis Megaspore Embryo (within a seed) Oospore Fertilisation (siphonogamous) Archegonia Oosphere (female gamete) Female prothallus (endosperm) Pinus tree Male strobilus Microsporophylls Microsporangia (pollen sacs) Microspore mother cells Meiosis Microspores (pollen grains shed) Male prothallus (vestigial) Body cell Male gamete (Monoecious) Diploid (2 ) n Haploid ( ) n Pinus : Topographical representation of life cycle
Economic Importance Angiospermae (Gk. Angion–vessel; sperma–seed) Angiosperms constitute a distinct group of flowering plants, which form covered seeds. With about 2,50,000 species, it can be regarded as the most successful group of plants. They arose in middle of Cretaceous period. General Characteristics (i) Angiosperms range from microscopic Wolffia to the largest tree such as Eucalyptus. (ii) The pollen grains and ovules develop in their flowers and the seeds are formed within the fruits. (iii) Nutritionally, they may be autotrophic (wheat, corn, etc.), parasitic (Cuscuta, Santalum, etc.), saprophytic (Monotrapa, etc.) and insectivorous (Drosera, Utricularia, etc.). (iv) They may be herb, shrub and trees. (v) Their lifetimes may be ephemeral, annual, biennial and perennial. (vi) Angiosperms are adapted to various habitats, as they may be hydrophytes, xerophytes and mesophytes. (vii) A flower is a modified shoot comprising of four whorls, i e . ., sepal, petal, androecium and gynoecium. Plant Kingdom 39 • • • Food Tuber and seeds of Seeds of sp. Chilgoza from sp. Cycas. Gnetum Pinus Industrial Products • • • amber Paper from pulp of sp. Methyl alcohol, terpentine and resin from sp. The fossilised resin of is known as , used in jewellery and X-ray sheets. Pinus Pinus Pinus excelsa Medicines • • • Resin of is used to treat ulcers. Ephedrine from (treatment of asthma). Resin of is used in stomach problem and to treat gonorrhoea. C. rumphii Ephedra Pinus Furniture • • Wood of . Wood of and are also used. Pinus Ephedra Gnetum Ornamentals Almost all gymnosperms are grown for ornamentation purpose. Academic Both extinct and extant species of gymnosperms help in studying the process of evolution. Gymnosperms
Classification of Angiosperms A natural system of classification was given by George Bentham and JD Hooker in 1862-63 in his book Genera Plantarum (3 volumes) in Latin. The outline of the above mentioned classification is as follows Some important plant families with their representative genera are as follows Ranunculaceae, Brassicaceae (e.g., mustard), Malvaceae (e g . ., gurhal), Asteraceae (e.g., sunflower), Lamiaceae (e.g., tulsi), Solanaceae (e.g., potato), Leguminosae (e.g., pea), Cucurbitaceae, Euphorbiaceae, Orchidaceae, Palmae (e.g., cashewnut), Poaceae (e.g., paddy) and Liliaceae (e.g., onion), etc. Reproduction in Angiosperms Angiosperms are plants that bear fruits and flowers. These flowers are plant’s reproductive structures. Reproduction in angiosperms (mostly sexual type) occurs when the pollen from an anther is transferred to stigma. When the ovules get fertilised, they will develop into seeds. Non-reproductive structures like petals, sepals etc. of the flowers fall off leaving only the ovary behind, which will develop into a fruit. 40 Handbook of Biology Phanerogamia (seed plants in which sex organs are evident) Dicotyledonae Gymnospermae Monocotyledonae Classes Polypetalae Gamopetalae Monochlamydeae Cycadaceae Coniferae Gnetaceae Sub-classes Sub-classes
Economic Importance Alternation of Generations It can also be termed as ‘Patterns of life cycle’. Plants divide mostly through mitotic divisions and form different plant bodies (these may be haploid or diploid). The interconversion of the haploid and diploid plant body in alternate manner is called alternation of generations. Generally, it is of three types Plant Life Cycles (i) Haplontic Sporophytic generation is not prominent, e.g., algae, etc. Plant Kingdom 41 Gametophytic plant Germination Gametangia Meiospores Zygotic meiosis Zygote Gametes Syngamy Haploid phase ( ) n Diploid phase (2 ) n Diagrammatic outline of a haplontic life cycle Furniture Wood from angiosperms. Food Grain, cereals and fruits. Ornamental Flowering plant. Decoration material. Vegetables Industrial Paper industry. Cosmetics. Baking industries. Environment Biodiversity Air purification. Medicines Antibiotics Alkaloids Aesthetic/Sacred Several plants have sacred importance, tulsi, peepal, etc. e.g., Important food component. Protein source. • • • • • • • • • Angiosperms • • Useful applications of angiosperms
42 Handbook of Biology (ii) Diplontic Gametophytic generation is of very short duration, e.g., gymnosperms and angiosperms, etc. (iii) Haplo-Diplontic Both gametophytic (n) and sporophytic (2n) are free-living, independent and multicellular phases, e.g., bryophytes, pteridophytes, etc. Diploid (2 ) n Haploid ( ) n Sporophytic plant Germination Sporangium Zygote Sporogenic meiosis Syngamy Gametes Sex organs Meiospores Germination Gametophytic plant Diagrammatic outline of a haplo-diplontic life cycle Sporophytic plant Zygote Gametogenic meiosis Gametes Gametes Gametangia Germination Syngamy Diploid phase (2 ) n Haploid phase ( ) n Diagrammatic outline of a diplontic life cycle Types of Meiosis Seen in Different Life Cycles Sporic Meiosis (in diplo-haplontic life cycle), etc. e.g., Ectocarpus, Laminaria, Zygotic Meiosis (in haplontic life cycle), . e.g., Volvox, Spirogyra Gametic Meiosis (in diplontic life cycle), Diatoms, etc. e.g., Sargassum,
4 Animal Kingdom Kingdom Animalia is characterised by multicellular, eukaryotic animal forms. It is also known as Metazoa. It includes around 1.2 million species of animals from sponges to mammals (other than protozoans). Metazoa Mesozoa Enterozoa Radiata Bilateria Deuterostomia Parazoa Worm-like bilateral symmetry, parasitic on cephalopods and other invertebrates, Phylum–Mesozoa. e.g., Cells loosely organised, no organs, no digestive cavity, Phylum–Porifera. e.g., True tissues present, a digestive cavity present also called Eumetazoa. Bilateral symmetry, organ systems present, triploblastic, digestive tract complete. Mouth not from blastopore mesoderm develops from archenteron, Phylum–Echinodermata, Hemichordata and Chordata. e.g., Eucoelomata (Schizocoela) Contains true coelom, Phylum–Annelida, Arthropoda and Mollusca, along with , , etc. (minor phyla). e.g., Sipuncula Onychophora Divisions Sub-divisions Radial or biradial symmetry no organs, diploblastic, Phylum–Coelenterata and Ctenophora. e.g., Protostomia Mouth from blastopore, cleavage spiral and determinate. Acoelomata Contains no coelom, Phylum–Platyhelminthes. e.g., Sections Pseudocoelomata Contains pseudocoelom, Phylum–Nematoda. e.g., Infra kingdoms or branches Classification of Metazoa
44 Handbook of Biology Ostracodermi Cyclostomata Two classes Extinct class, e.g., Pteraspis, Contains 1-16 pairs of gill slits. Head and brain are poorly developed. Endoskeleton is cartilaginous. Two-chambered heart. Fertilisation is external and development is indirect, (lamprey), (hagfish). e.g., Petromyzon Myxine • • • • • • Phylum–Chordata Urochordata (Tunicates) Vertebrata (Craniata) Notochord is replaced by vertebral column. Notochord is present in embryonic stage only. Body is either segmented or unsegmented. Cephalochordata Three sub-phyla Notochord is restricted in the posterior part of the body (tail region). Notochord is present in larval stage only. Body is unsegmented, e.g., Herdmania. • • • • Notochord is extended in the head region. Notochord is present throughout the life. Body is segmented, e.g., Amphioxus. • • • • • Agnatha (Jawless) Gnathostomata (Bear jaws) Mouth bears jaws. Embryonic notochord is replaced in adults by a vertebral column. Paired appendages (fins or limbs) are present. Nostrils are paired. Internal ear has three semicircular canals. There are 10-12 pairs of cranial nerves. Mouth does not possess jaws. Notochord persists throughout life. Paired appendages are absent. Single nostril is present. Internal ear has two or one semicircular canals. 8-10 pairs of cranial nerves, are present. • • • • • • • Two divisions • • • • • (True coelomates with enterocoelic type of coelom) Pisces Tetrapoda Two super-classes Fins are present. Respire by gills. Do not have internal nares (except lungfish). Heart is two or three-chambered. They have internal ears. Limbs are present. Respire by lungs, gills and skin. They have internal nares. Heart is three or four-chambered. They have internal, middle and external ears (except snakes). • • • • • • • • • • Chondrichthyes (Cartilaginous fishes) Aves Amphibia Reptilia Mammalia Four classes Three classes Placodermi (Extinct) Osteichthyes (Bony fishes) Classification of Phylum Chordata
Basis of Classification There are few fundamental common features to various animal groups, which form the basis of classification. These features are as follows 1. Level of Organisation Though, all the members of kingdom–Animalia are multicellular, yet all of them do not exhibit the same pattern of cellular organisation. Different levels of organisation are discussed below 2. Symmetry It refers to the correspondence of body parts in all major respect like size, shape, position, etc., with the parts on opposite side when divided from the central axis. Types of symmetry found in animals are (i) Radial symmetry In radial symmetry, the animal gets divided into two ‘identical halves’ when any plane passes through the central axis, e.g., coelenterates, echinoderms. (ii) Bilateral symmetry In bilateral symmetry, body is divided into two ‘identical halves’ only when a plane passes through the median longitudinal axis, e.g., annelids, arthropods, etc. 3. Germ Layers These are the groups of cells behaving as a unit during early stages of embryonic development. On the basis of number of germ layers, animals are placed in two groups, i.e., diploblastic and triploblastic. These groups are divided at the gastrulation stage. Animal Kingdom 45 Acellular or Protoplasmic Level Body consists of mass of protoplasm. All activities are performed by different cell organelles and confined within the limit of plasma membrane, Protozoa. e.g., Cellular Level Body consists of many cells which either forms an aggregate or a colony. It is of two types Cellular colony Protists and some algae. Cellular aggregate Porifera (sponges), where cells are not organised into tissue. Tissue Level Group of similar cells forms tissues which serves specific functions, coelenterates. e.g., Organ Level Some tissues join and function as a unit of a organ, Stomach (one of digestive organs) contains all tissues, Platyhelminthes. e.g., e.g., Organ-System Level Group of organs working together to forms organ system, Organs such as stomach, intestine, etc., aid in digestion and constitute digestive system, Nemathelminthes to chordates. e.g., e.g., Levels of Organisation (i) (ii)
(i) Diploblastic Embryo is two-layered consisting an outer ectoderm and inner endoderm, e.g., Hydra, jellyfish, etc. (ii) Triploblastic Embryo is three-layered consisting of an outer ectoderm, middle mesoderm and inner endoderm, e.g., humans. 4. Coelom It is a large fluid-filled space or cavity lying between the outer body wall and inner digestive tube. 46 Handbook of Biology Types of Coelom Internal body cavity separates digestive tract from outer body wall Acoelom parenchyma There is no body cavity. Region between the ectodermal epidermis and the endodermal digestive tract is completely filled with mesoderm in the form of a spongy mass of space filling cells called Porifera, Coelenterata, Ctenophora and Platyhelminthes. e.g., . Pseudocoelom The presence of false coelom or perivisceral cavity. Coelom is not lined by mesoderm and directly connected to archenteron. Developmentally, pseudocoelom is the persistent blastocoel of blastula stage, Rotifera, Aschelminthes and Nematoda. e.g., Eucoelom or True Coelom True body cavity develops entirely lined with the mesoderm, higher invertebrates (Annelida, Echinodermata and Chordata). e.g., Schizocoel Developed as a split in the mesoderm sheet, Annelida to Arthropoda. Protostomes are schizocoelous. e.g., Enterocoel Formed from the pouches of the archenteron or primitive gut. Echinodermata and chordata. Deuterostomes are enterocoelous. e.g., Coelomate Pseudocoelomate Acoelomate Pseudocoelom Ectoderm Ectoderm Endoderm Endoderm Mesoderm Endoderm Coelom Ectoderm Digrammatic sectional view of coelom
5. Segmentation It is the serial repetition of similar parts along the length of an animal. It is of two types (i) Pseudosegmented (strobilisation) Body is divided into number of pseudosegments (proglottids) which are independent of each other, e.g., tapeworms. (ii) Metameric Linear repetition of body parts (somites), e.g., annelids, arthropods and chordates. 6. Notochord It is a rod-like structure present on the dorsal side of the animal body. It is derived from the embryonic mesoderm. Based on its presence and absence, animals are non-chordates (phylum–Porifera to Echinodermata) and chordates (phylum–Chordata). Major differences between Chordata and Non-Chordata are as follows Chordata Non-Chordata Bilaterally symmetrical. Asymmetrical, radially symmetrical or bilaterally symmetrical. True metamerism. Non-segmented, false segmented or true metamerically segmented. True coelomates. Acoelomate, pseudocoelomate or true coelomates. Post-anal tail usually present. It is usually absent. Triploblastic animals. Cellular, diploblastic or triploblastic animals. Alimentary canal is always ventrally placed to nerve cord. Heart is ventrally placed. It is always dorsally placed to the nerve cord. Heart is dorsal or absent. Central nervous system is hollow, dorsal and single. Central nervous system is ventral, solid and double. Pharynx is perforated by gill slits. Gill slits are absent. Phylum–Porifera Poriferans bear numerous minute pores called ostia on the body wall, which leads into a central cavity called spongocoel or paragastric cavity. The spongocoel opens to outside by osculum. Animal Kingdom 47
Majority of poriferans (sponges) are marine and sedantry. They are diploblastic animals and contain an outer dermal layer of pinacocytes and inner gastral layer of choanocytes. Canal System (Aquiferous system) It is a system of interconnected canals through which water circulates and helps in a number of metabolic activities of a sedentary sponge. In sponges, canal system is of three types, i e . ., asconoid, syconoid and leuconoid. Different Types of Canal System Asconoid Canal System Syconoid Canal System Leuconoid Canal System Simplest type with thin walls. Complex type with thick walls. Much complex type with highly folded thick walls. Spongocoel is large and spacious. Spongocoel is narrow. Spongocoel is either reduced or absent. 48 Handbook of Biology Flagellum Collar Protoplasmic processes Microvilli Basal granule Rhizoplast Blepharoplast Nucleus Cytoplasm Flagellum (create water current) Collar microvillus (filter particles from water) Endoplasmic reticulum Nucleus Mitochondrion Food vacuole Contractile vacuole (b) (a) Choanocyte : (a) Light microscopic view (b) Electron microscopic view
Asconoid Canal System Syconoid Canal System Leuconoid Canal System Choanocytes form the gastral layer and lines the whole spongocoel. Choanocytes are restricted in radial canals only. Choanocytes are confined in the flagellated chambers which are formed by the evagination of radial canals. Route of water is Outside water  Dermal Ostia Outside ← Osculum Spongocoel e g . ., Leucosolenia. Route of water is Outside water  Dermal  Prosopyle Incurrent canal Radial canal  Apopyle  Gastral Ostia Excurrent canal Spongocoel → Osculum Outside e.g., Grantia. Route of water is Outside water Ostia Dermal   Hypodermalspaces Incurrent canals Prosopyle   Apopyle Flagellated chambers Excurrent canal   Osculum Excurrent spaces Outside, e g . ., Plakina. Reproduction In sponges, reproduction occurs by both asexual and sexual means. (i) Asexual reproduction Mainly occurs by budding and gemmules. (ii) Sexual reproduction Occurs with the help of amoebocyte or archeocytes or sometimes through choanocytes. Classification of Porifera Animal Kingdom 49 Ostia Phylum–Porifera Calcispongiae or Calcarea Demospongiae Hyalospongiae or Hexactinellida Three classes Skeleton of calcareous spicules. Large choanocytes. Small-sized species. Skeleton of siliceous spicules. Small choanocytes. Moderately-sized species. Skeleton of spongin fibres or may be absent. Very small choanocytes. Large-sized species. • • • • • • • • •
Common and Scientific Names of Some Members of Porifera Common Species of Porifera Scientific Name Common Species of Porifera Scientific Name Glass rope sponge Hyalonema Venus flower basket Euplectella Bath sponge Euspongia Bowl sponge Pheronema Freshwater sponge Spongilla Dead man’s finger sponge Chalina Urn sponge Scypha Boring sponge Cliona Economic Importance l They are used commercially for bathing/cleaning sponges. l They help to clean-up the ocean floor by boring into dead shells and corals releasing chemicals to break them down. Phylum–Coelenterata (Cnidaria) Coelenterates are the animals bearing a special body cavity called coelenteron (gastrovascular cavity). They exhibit dimorphism and display two major forms namely polyp (sedentary) and medusa (swimming). They also exhibit trimorphism (e.g., Siphonophora) and polymorphism (e.g., Porpita). Body Wall They are diploblastic animals and their body wall contains several types of cells, e.g., stinging cells (cnidoblast/nematocyst), interstitial cells (totipotent cells), sensory cells, nerve cells, etc. 50 Handbook of Biology (a) (b) Lasso Shaft or butt Barbules Operculum Nematocyst Barb Coiled thread Muscular fibrils Nucleus Nematoblast Cnidocil Lasso Nucleus Muscular fibrils Nematocyst Operculum Shaft or butt Barb Barbules Everted thread Cnidocil Cnidoblast Cells : (a) Undischarged (b) Discharged
Skeleton In coelenterates, skeleton may be endoskeleton, exoskeleton or absent. l Endoskeleton e.g., Alcyonium (fleshy mesogloea), Pennatula (axial rod of calcified horn). l Exoskeleton e.g., Millipore (coenosteum), Gorgonia (gorgorin), Madrepora (corallum). l Absent e.g., sea anemones. Metagenesis It is like the alternation of generations between the sexual (medusa) and asexual (polyp) forms. In contrast to alternation of generation in metagenesis, it is difficult to distinguish between asexual and sexual forms as both individuals are diploid. Reproduction It occurs both by sexual and asexual means. (i) Asexual reproduction By external budding. (ii) Sexual reproduction By sexual medusae. The development is usually indirect which occurs through ephyra, planula and hydrula larvae. Classification of Coelenterata Common and Scientific Names of Some Coelenterates Common Names of Coelenterates Scientific Name Common Names of Coelenterates Scientific Name Sail-by-wind Valella Organ-pipe coral Tubipora Portuguese man of war Physalia Stag horn coral Madrepora Stinging coral Millipora Mushroom coral Fungia Sea anemone Metridium Star coral Astraea Dead’s man finger coral Alcyonium Animal Kingdom 51 Phylum–Coelenterata Hydrozoa Anthozoa (Actinozoa) Scyphozoa Three classes Both polyp and medusa present. Polyp stage dominant, medusa stage reduced or absent. Velum is present. Gonads are epidermal in origin. Larva hydrula, planula, Medusa form is dominant. Polyp represented as scyphistoma stage. Pseudovelum is present. Gonads are endodermal in origin. Larva ephyra. Gonads, if present are endodermal in origin. Corals and sea anemone. • • • • • Medusa form is absent. Velum is absent. • • • • • • •
Economic Importance l They take part in the formation of coral reefs, e.g., Millipora (stinging coral). l Their skeleton has medicinal value, e.g., Tubipora (organ-pipe coral). l They have ornamental value, e.g., Astraea (star coral). Phylum–Ctenophora The members of this phylum are generally marine, solitary, free-swimming or pelagic. They are diploblastic animals and acoelomates. Peculiar Characteristics A gelatinous mesoglea is present between epidermal and gastrodermal tissue layers. They are also called comb plates. Colloblast cells are the sensory and adhesive cells. Reproduction Sexes are not separate. All are hermaphrodites. Gonads develop from endosperm. Fertilisation is internal. Development is indirect through cydippid larva. Classification of Ctenophora Common and Scientific Names of Some Ctenophores Common Name of Ctenophores Scientific Name Venus Girdle Velamen Sea walnut Pleurobrachia Swimming eye of cat Beroe Economic Importance l They reproduce quickly and are good predators. l They can bring down an ecosystem. 52 Handbook of Biology Phylum–Ctenophora Tentaculata Nuda Two classes Possesses tentacles Contains two long aboral tentacles , , etc. e.g., Ctenoplana Velamen e.g., Beroe, etc. • • • Does not possess tentacles. Have a highly branched gastrovascular cavity. • • •
Phylum–Platyhelminthes They are dorsoventrally flat animals having either unsegmented and leaf-like (e.g., flukes) or segmented and ribbon-like (Taenia) body. They are the first animals to have bilateral symmetry and to undergo cephalisation. Habitat They are mostly found as free-living forms, but few of them are parasitic in their habitat. Peculiar Features These are the first animals with triploblastic layers in body wall and organ system organisation. They are acoelomates due to the presence of a mesodermal connective tissue, parenchyma, in between the visceral organs. These animals have ladder-type nervous system and peculiar cells called flame cells or protonephridia for excretion. These cells are modified mesenchymal cells. Animal Kingdom 53 Nucleus Pseudopodia Globules of excretion Basal granules Cell lumen Ciliary flame Termination of capillary duct Flame cell (Solenocyte) Ectoparasites ( and ) e.g., Diplozoon Gyrodactylus Endoparasites ( and ) e.g., Echinococcus Taenia Parasitic forms Freshwater ( and ) e.g., Dugesia Planaria Free-living forms Marine ( and ) e.g., Convoluta Thysanozoon Terrestrial ( and ) e.g., Bipalium Geoplana Platyhelminthes
Reproduction These animals are generally bisexual. Cross- fertilisation occurs in trematodes, while self-fertilisation occurs in cestodes. Fertilisation is always internal. Turbellarians reproduce by transverse fission. Life Cycle of Taenia solium 54 Handbook of Biology Fertilised ova (zygotes) in the mature proglottids capsules containing zygotes in gravid proglottids. Adult tapeworm in human gut Onchosphere (larvae) in the gravid proglottids. It contains all embryonic membranes along with a hexacanth (structure with 6 hooks). Onchospheres in human faeces (outside the body). Faeces containing onchospheres is eaten by pig. Hexacanth It is the six-hooked larval stage containing a pair of penetration glands. Each cysticercus develops into young tapeworm in the human gut. Cysticercus Hexacanth reaches heart liver and finally muscles tongue, shoulder, neck, thigh and settles to develop into next larval stage called cysticercus or bladder worm within 10 days of infection of the secondary host. It is the infective stage of human when they feed infected meat. via Bladder Neck showing strobilation Rostellar hooks Scolex Sucker (Cysticercus) Germ layer (Oncosphere) Bladder Hooks The graphical representation of life cycle of Taenia solium depicting different larval stages and adult form in the primary and secondary hosts
Life Cycle of Fasciola hepatica Classification of Plathelminthes Common and Scientific Names of Some Platyhelminthes Common Names of Platyhelminthes Scientific Name Common Names of Platyhelminthes Scientific Name Liver fluke Fasciola hepatica Pork tapeworm Taenia solium Planarian Dugesia Hydatid worm or dog tapeworm Echinococcus granulosus Animal Kingdom 55 Phylum–Platyhelminthes Turbellaria Cestoda Trematoda Three classes Mostly non-parasitic and free-living. Unsegmented and flat leaf-like. Body wall contains syncytial epidermis with rod-shaped rhabditis, e.g., Planaria. Exclusively endoparasites Segmented and ribbon-like. Body wall is lined by microvilli. e.g., Taenia. • • • • • • Ecto or endoparasites. Unsegmented and flat leaf-like. Body wall contains cuticular spines, e.g., Fasciola. • • • Adult in the liver of sheep Fasciola Large number of eggs in faecal matter of sheep. Development of egg into next larval stage miracidium. Miracidium First larval stage freely swim in water with the help of cilia present all over body. Penetrate secondary host snail reaches to salivary gland and forms second larval stage sporocysts. Sporocyst It is the second larvae of living in pulmonary tissues of snail and obtaining nutrition from it and develops into 5-8 rediae. Fasciola Rediae It is the most important larval stage and it bears an anterior end with a ring of collar, a birth pore and pair of projections (lappets or procruscula). During Winter Every rediae produces, 14-20 cercaria (next larval stage). It replicates giving rise to the same form, daughter rediae. During Summer i.e., Cercaria It escapes from the secondary host through pulmonary sac. Its tail help in swimming of the larvae in water. After 2-3 days, it loses its tail and becomes incepted on grass or aquatic plant and is now called letacercaria. Metacercaria This is the encysted infective stage of the and now infects vertebrate host (sheep). Fasciola Graphical representation of life cycle of Fasciola hepatica depicting polyembryony along with different larval stages
Economic Importance l Fasciola causes fascioliosis or liver rot which is characterised by hepatitis. l Echinococcus causes hydatid disease which is characterised by enlargement of liver. Phylum–Aschelminthes They are long, cylindrical, unsegmented and thread-like animals with no lateral appendages, so these are commonly called roundworms, bagworms or threadworms. Peculiar Features Body wall of these pseudocoelomate animals is composed of complex cuticle, syncytial epidermis and only longitudinal muscles. They have tube-within-tube plan of digestive system. They have fixed number of cells in every organ of the body (eutylic condition). Excretory system is H-shaped and contains rennete cells. Reproduction Sexual dimorphism is present and males are smaller than females. Fertilisation is internal and it may be direct or indirect. 56 Handbook of Biology Females Ova Males Sperms → → → → (4th moult) Back to intestine In stomach In oesophagus Swallowed into gullet In pharynx In trachea In bronchi In bronchioles Fourth stage juvenile (3rd moult) Third stage juvenile (2nd moult) Bores into lung alveoli (stays for 10 days) In lung capillaries ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ Spiral, determinate cleavage First stage juvenile or rhabditi- form larva (first moult) Second stage juvenile Embryonated egg swallowed by human host Egg hatches out in intestine Bores through intestinal wall into blood capillaries In mesenteric vein In hepatic portal vein In liver capillaries In hepatic vein ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ In pulmonary artery Right auricle In posterior vena cava ← ← Adults ↑ 3-4 days Liver Lungs 5 days (Secondary Migration) (Primary Migration) 3-4 days Heart ↓ ↑ Fertilised eggs out with host faeces ↓ Life cycle of Ascaris A graphical representation of life cycle of Ascaris
Classification of Aschelminthes Common and Scientific Names of Some Aschelminthes Common Names of Aschelminthes Scientific Name Common Names of Aschelminthes Scientific Name Roundworm Ascaris lumbricoides Guinea worm Dracunculus medinesis Root-knot eel worm Meloidogyne marioni Pinworm Enterobius vermicularis Filarial worm Wuchereria bancrofti Whipworm Trichuris trichiura Eye worm Loa loa Economic Importance l Ascaris causes ascariasis in humans. l Meloidogyne is a harmful phytoparasitic nematode. Phylum–Annelida Annelids are segmented worms with an elongated body possessing triploblastic layers. Their musculature is formed of only smooth muscle fibres of two types, i.e., longitudinal (inner) and circular (outer) muscles. Animal Kingdom 57 Phylum–Aschelminthes Nematoda Body wall have cuticle, epidermis and longitudinal muscles. Excretory system is formed of renette cells. Nematophora Rotifera Gastrotricha Kinorhyncha Cuticle is highly thickened and formed of collagen fibres. Excretory system absent. Cuticle is formed of plates (lorica) and body wall contains both circular and longitudinal muscles. Formed of two protonephridia. Cuticle is produced into short spines. Formed of two protonephridia. Cuticle is spiny, but without cilia. • • • • • • • • Aphasmida Phasmida Phasmids, caudal sensory organs are present, , , , , , , , etc. i.e., e.g., Anguina Ancylostoma Ascaris Enterobius Dracunculus Wuchereria Loa loa Without phasmids, the caudal sensory organs. Usually free-living, and , etc. i.e., e.g., Trichinella Trichuris •
Peculiar Features l These animals show metameric segmentation, i.e., the external division of the body by annuli corresponds to internal division of coelom by septa. l These are the first animals to have circulatory system. l Locomotory organs are minute rod-like chitinous setae or suckers which are embedded over parapodia. l A characteristic circumoesophageal ring is present in the anterior part of CNS. l Special structures called nephridia are present for excretion. Reproduction Asexual reproduction By fragmentation is seen in some polychaetes. Sexual reproduction Sexes are either united (e.g., oligochaetes) or separate (e.g., polychaetes). Fertilisation is internal (e.g., Hirudinaria) or external (e.g., earthworm). Development is direct in monoecious form and indirect in dioecious form involving a free-swimming trochophore larva. Classification of Annelida Common and Scientific Names of Some Annelids Common Names of Annelids Scientific Names Common Names of Annelids Scientific Names Earthworm Pheretima posthuma Paddle worm Chaetopterus Clam worm Nereis Blood worm Glycera Polalo worm Eunice Skate sucker Pontobdella Sea mouse Aphrodite Lung worm Arenicola 58 Handbook of Biology Phylum–Annelida Polychaeta Hirudinea Oligochaeta Three classes Marine, fossorial or tubicolous. Distinct head bearing tentacles, palps and eyes. Bristle-like setae and parapodia for locomotion Clitellum is absent. Unisexual, and e.g., Aphrodite Chaetopterus. Mostly freshwater, few marine. No cephalisation Locomotion by anterior and posterior suckers. Clitellum appears during breeding season. Bisexual, and e.g., Hirudinaria Acanthobdella. • • • • • • Terrestrial, freshwater Distinct head with eyes (palps and tentacles are absent). Locomotion by peristalsis, parapodia is absent. Permanent clitellum is present. Bisexual, and e.g., Pheretima Tubifex. • • • • • • • • •
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf
Arihant handbook biology for class 11 .pdf

Recommended

Seed dispersal
Seed dispersalSeed dispersal
Seed dispersal
Soha Bedair
 
पेशी रचना व सूक्ष्मजीव
पेशी रचना व सूक्ष्मजीव पेशी रचना व सूक्ष्मजीव
पेशी रचना व सूक्ष्मजीव
Jnana Prabodhini Educational Resource Center
 
Plant kingdom
Plant kingdomPlant kingdom
Plant kingdom
martagar78
 
Parts of Flower and types
Parts of Flower and typesParts of Flower and types
Parts of Flower and types
Roshan Parihar
 
Bentham and hooker system of classification
Bentham and hooker system of classificationBentham and hooker system of classification
Bentham and hooker system of classification
Maratha Vidya Prasarak Samaj's Arts, Commerce & Science College, Tryambakeshwar
 
Angiosperms and Gymnosperms.ppt
Angiosperms and Gymnosperms.pptAngiosperms and Gymnosperms.ppt
Angiosperms and Gymnosperms.ppt
GraceAceveda
 
food chains and Relationships
food chains and Relationships food chains and Relationships
food chains and Relationships
Karl Pointer
 
Introduction to botany
Introduction to botanyIntroduction to botany
Introduction to botany
Umama Akram Rai
 

Recommended

Seed dispersal
Seed dispersalSeed dispersal
Seed dispersal
Soha Bedair
 
पेशी रचना व सूक्ष्मजीव
पेशी रचना व सूक्ष्मजीव पेशी रचना व सूक्ष्मजीव
पेशी रचना व सूक्ष्मजीव
Jnana Prabodhini Educational Resource Center
 
Plant kingdom
Plant kingdomPlant kingdom
Plant kingdom
martagar78
 
Parts of Flower and types
Parts of Flower and typesParts of Flower and types
Parts of Flower and types
Roshan Parihar
 
Bentham and hooker system of classification
Bentham and hooker system of classificationBentham and hooker system of classification
Bentham and hooker system of classification
Maratha Vidya Prasarak Samaj's Arts, Commerce & Science College, Tryambakeshwar
 
Angiosperms and Gymnosperms.ppt
Angiosperms and Gymnosperms.pptAngiosperms and Gymnosperms.ppt
Angiosperms and Gymnosperms.ppt
GraceAceveda
 
food chains and Relationships
food chains and Relationships food chains and Relationships
food chains and Relationships
Karl Pointer
 
Introduction to botany
Introduction to botanyIntroduction to botany
Introduction to botany
Umama Akram Rai
 
Kingdom Fungi
Kingdom FungiKingdom Fungi
Kingdom Fungi
MrsTabor
 
The plant kingdom
The plant kingdomThe plant kingdom
The plant kingdom
Kaustubh Vyas
 
History of taxonomyyyyy
History of taxonomyyyyyHistory of taxonomyyyyy
History of taxonomyyyyy
Raccoon30
 
Animal kingdom
Animal kingdomAnimal kingdom
Animal kingdom
Anurag Verma
 
Biology M4 Fruit and Seed Dispersal
Biology M4 Fruit and Seed DispersalBiology M4 Fruit and Seed Dispersal
Biology M4 Fruit and Seed Dispersal
eLearningJa
 
Thallopyte
ThallopyteThallopyte
Thallopyte
MacVasquez
 
Characters of acanthaceae
Characters of acanthaceaeCharacters of acanthaceae
Characters of acanthaceae
University of Allahabad
 
TNSCERT Unit 17 animal kingdom
TNSCERT Unit 17 animal kingdomTNSCERT Unit 17 animal kingdom
TNSCERT Unit 17 animal kingdom
KavithaSathish5
 
Seed Dispersal
Seed DispersalSeed Dispersal
Seed Dispersal
divyajot
 
Invertebrates modificado
Invertebrates modificadoInvertebrates modificado
Invertebrates modificado
avaldesabril
 
Gynoecium
GynoeciumGynoecium
Gynoecium
NithyaNandapal
 
Seed dispersal
Seed dispersalSeed dispersal
Seed dispersal
Vani Mp
 
fertilization in plants
fertilization in plantsfertilization in plants
fertilization in plants
UMMACHA
 
The Fundamental Unit Of Life Class 9th By ADHWEAT GUPTA
The Fundamental Unit Of Life Class 9th By ADHWEAT GUPTAThe Fundamental Unit Of Life Class 9th By ADHWEAT GUPTA
The Fundamental Unit Of Life Class 9th By ADHWEAT GUPTA
Adhweat Gupta
 
Plant Kingdom
Plant KingdomPlant Kingdom
Plant Kingdom
itutor
 
structure of flower
structure of flower structure of flower
structure of flower
anoop kp
 
Coevolution
CoevolutionCoevolution
Coevolution
sherylwil
 
Seed dispersal
Seed dispersalSeed dispersal
Seed dispersal
ghazalanoreen
 
Evolution
EvolutionEvolution
Evolution
Dobbs Ferry High School
 
Bentham hooker classification system
Bentham hooker classification systemBentham hooker classification system
Bentham hooker classification system
Devender Singh Meena
 
Arihant Biology 34 Years NEET PYQ.pdf
Arihant Biology 34 Years NEET PYQ.pdfArihant Biology 34 Years NEET PYQ.pdf
Arihant Biology 34 Years NEET PYQ.pdf
NishaSingh375666
 
Atul Butte's presentation at the 2015 AMIA Fall Symposium
Atul Butte's presentation at the 2015 AMIA Fall SymposiumAtul Butte's presentation at the 2015 AMIA Fall Symposium
Atul Butte's presentation at the 2015 AMIA Fall Symposium
University of California, San Francisco
 

More Related Content

What's hot

Kingdom Fungi
Kingdom FungiKingdom Fungi
Kingdom Fungi
MrsTabor
 
History of taxonomyyyyy
History of taxonomyyyyyHistory of taxonomyyyyy
History of taxonomyyyyy
Raccoon30
 
The Fundamental Unit Of Life Class 9th By ADHWEAT GUPTA
The Fundamental Unit Of Life Class 9th By ADHWEAT GUPTAThe Fundamental Unit Of Life Class 9th By ADHWEAT GUPTA
The Fundamental Unit Of Life Class 9th By ADHWEAT GUPTA
Adhweat Gupta
 
Plant Kingdom
Plant KingdomPlant Kingdom
Plant Kingdom
itutor
 

What's hot (20)

Kingdom Fungi
Kingdom FungiKingdom Fungi
Kingdom Fungi
 
The plant kingdom
The plant kingdomThe plant kingdom
The plant kingdom
 
History of taxonomyyyyy
History of taxonomyyyyyHistory of taxonomyyyyy
History of taxonomyyyyy
 
Animal kingdom
Animal kingdomAnimal kingdom
Animal kingdom
 
Biology M4 Fruit and Seed Dispersal
Biology M4 Fruit and Seed DispersalBiology M4 Fruit and Seed Dispersal
Biology M4 Fruit and Seed Dispersal
 
Thallopyte
ThallopyteThallopyte
Thallopyte
 
Characters of acanthaceae
Characters of acanthaceaeCharacters of acanthaceae
Characters of acanthaceae
 
TNSCERT Unit 17 animal kingdom
TNSCERT Unit 17 animal kingdomTNSCERT Unit 17 animal kingdom
TNSCERT Unit 17 animal kingdom
 
Seed Dispersal
Seed DispersalSeed Dispersal
Seed Dispersal
 
Invertebrates modificado
Invertebrates modificadoInvertebrates modificado
Invertebrates modificado
 
Gynoecium
GynoeciumGynoecium
Gynoecium
 
Seed dispersal
Seed dispersalSeed dispersal
Seed dispersal
 
fertilization in plants
fertilization in plantsfertilization in plants
fertilization in plants
 
The Fundamental Unit Of Life Class 9th By ADHWEAT GUPTA
The Fundamental Unit Of Life Class 9th By ADHWEAT GUPTAThe Fundamental Unit Of Life Class 9th By ADHWEAT GUPTA
The Fundamental Unit Of Life Class 9th By ADHWEAT GUPTA
 
Plant Kingdom
Plant KingdomPlant Kingdom
Plant Kingdom
 
structure of flower
structure of flower structure of flower
structure of flower
 
Coevolution
CoevolutionCoevolution
Coevolution
 
Seed dispersal
Seed dispersalSeed dispersal
Seed dispersal
 
Evolution
EvolutionEvolution
Evolution
 
Bentham hooker classification system
Bentham hooker classification systemBentham hooker classification system
Bentham hooker classification system
 

Similar to Arihant handbook biology for class 11 .pdf

Complementary and alternative therapies for erectile dysfunction
Complementary and alternative therapies for erectile dysfunctionComplementary and alternative therapies for erectile dysfunction
Complementary and alternative therapies for erectile dysfunction
Naina Mohamed, PhD
 
Presentation by Atul Butte at the NSTC Interagency Working Group on Biologica...
Presentation by Atul Butte at the NSTC Interagency Working Group on Biologica...Presentation by Atul Butte at the NSTC Interagency Working Group on Biologica...
Presentation by Atul Butte at the NSTC Interagency Working Group on Biologica...
University of California, San Francisco
 
srep15786.pdf GWAS corr AyurVeda Prakriti
srep15786.pdf GWAS corr AyurVeda Prakritisrep15786.pdf GWAS corr AyurVeda Prakriti
srep15786.pdf GWAS corr AyurVeda Prakriti
Shalendra Roepan
 
pms_optional_papers.pdf
pms_optional_papers.pdfpms_optional_papers.pdf
pms_optional_papers.pdf
Totifruti
 
Pms optional papers
Pms optional papersPms optional papers
Pms optional papers
shahid khan
 

Similar to Arihant handbook biology for class 11 .pdf (20)

Arihant Biology 34 Years NEET PYQ.pdf
Arihant Biology 34 Years NEET PYQ.pdfArihant Biology 34 Years NEET PYQ.pdf
Arihant Biology 34 Years NEET PYQ.pdf
 
Atul Butte's presentation at the 2015 AMIA Fall Symposium
Atul Butte's presentation at the 2015 AMIA Fall SymposiumAtul Butte's presentation at the 2015 AMIA Fall Symposium
Atul Butte's presentation at the 2015 AMIA Fall Symposium
 
Class 11 Cbse Biology Syllabus 2013-14
Class 11 Cbse Biology Syllabus 2013-14Class 11 Cbse Biology Syllabus 2013-14
Class 11 Cbse Biology Syllabus 2013-14
 
Translating a Trillion Points of Data into Therapies, Diagnostics, and New In...
Translating a Trillion Points of Data into Therapies, Diagnostics, and New In...Translating a Trillion Points of Data into Therapies, Diagnostics, and New In...
Translating a Trillion Points of Data into Therapies, Diagnostics, and New In...
 
Atul Butte's presentation at JGI March 2015
Atul Butte's presentation at JGI March 2015Atul Butte's presentation at JGI March 2015
Atul Butte's presentation at JGI March 2015
 
Atul Butte's AAPS keynote presentation 6/2015
Atul Butte's AAPS keynote presentation 6/2015Atul Butte's AAPS keynote presentation 6/2015
Atul Butte's AAPS keynote presentation 6/2015
 
Khurana Review of Ophthalmology 2015.pdf
Khurana Review of Ophthalmology 2015.pdfKhurana Review of Ophthalmology 2015.pdf
Khurana Review of Ophthalmology 2015.pdf
 
Khurana Review of Ophthalmology 2015 .
Khurana Review of Ophthalmology 2015 .Khurana Review of Ophthalmology 2015 .
Khurana Review of Ophthalmology 2015 .
 
Precision Medicine World Conference 2017
Precision Medicine World Conference 2017Precision Medicine World Conference 2017
Precision Medicine World Conference 2017
 
Atul Butte's presentation at the From Data to Discovery symposium at Westat
Atul Butte's presentation at the From Data to Discovery symposium at WestatAtul Butte's presentation at the From Data to Discovery symposium at Westat
Atul Butte's presentation at the From Data to Discovery symposium at Westat
 
Complementary and alternative therapies for erectile dysfunction
Complementary and alternative therapies for erectile dysfunctionComplementary and alternative therapies for erectile dysfunction
Complementary and alternative therapies for erectile dysfunction
 
Name that Organ PowerPoint Quiz.pptx
Name that Organ PowerPoint Quiz.pptxName that Organ PowerPoint Quiz.pptx
Name that Organ PowerPoint Quiz.pptx
 
Presentation by Atul Butte at the NSTC Interagency Working Group on Biologica...
Presentation by Atul Butte at the NSTC Interagency Working Group on Biologica...Presentation by Atul Butte at the NSTC Interagency Working Group on Biologica...
Presentation by Atul Butte at the NSTC Interagency Working Group on Biologica...
 
srep15786.pdf GWAS corr AyurVeda Prakriti
srep15786.pdf GWAS corr AyurVeda Prakritisrep15786.pdf GWAS corr AyurVeda Prakriti
srep15786.pdf GWAS corr AyurVeda Prakriti
 
Introduction to Biochemistry, cell and cell organelles
Introduction to Biochemistry, cell and cell organellesIntroduction to Biochemistry, cell and cell organelles
Introduction to Biochemistry, cell and cell organelles
 
pms_optional_papers.pdf
pms_optional_papers.pdfpms_optional_papers.pdf
pms_optional_papers.pdf
 
Pms optional papers
Pms optional papersPms optional papers
Pms optional papers
 
Sustainability in preclinical drug discovery.pptx
Sustainability in preclinical drug discovery.pptxSustainability in preclinical drug discovery.pptx
Sustainability in preclinical drug discovery.pptx
 
2013 03 genomic medicine slides
2013 03 genomic medicine slides2013 03 genomic medicine slides
2013 03 genomic medicine slides
 
Astromed doctor perspective
Astromed doctor perspectiveAstromed doctor perspective
Astromed doctor perspective
 

Recently uploaded

Call Girls in Uttam Nagar (delhi) call me [🔝9953056974🔝] escort service 24X7
Call Girls in Uttam Nagar (delhi) call me [🔝9953056974🔝] escort service 24X7Call Girls in Uttam Nagar (delhi) call me [🔝9953056974🔝] escort service 24X7
Call Girls in Uttam Nagar (delhi) call me [🔝9953056974🔝] escort service 24X7
9953056974 Low Rate Call Girls In Saket, Delhi NCR
 
Spellings Wk 4 and Wk 5 for Grade 4 at CAPS
Spellings Wk 4 and Wk 5 for Grade 4 at CAPSSpellings Wk 4 and Wk 5 for Grade 4 at CAPS
Spellings Wk 4 and Wk 5 for Grade 4 at CAPS
AnaAcapella
 

Recently uploaded (20)

Call Girls in Uttam Nagar (delhi) call me [🔝9953056974🔝] escort service 24X7
Call Girls in Uttam Nagar (delhi) call me [🔝9953056974🔝] escort service 24X7Call Girls in Uttam Nagar (delhi) call me [🔝9953056974🔝] escort service 24X7
Call Girls in Uttam Nagar (delhi) call me [🔝9953056974🔝] escort service 24X7
 
HMCS Vancouver Pre-Deployment Brief - May 2024 (Web Version).pptx
HMCS Vancouver Pre-Deployment Brief - May 2024 (Web Version).pptxHMCS Vancouver Pre-Deployment Brief - May 2024 (Web Version).pptx
HMCS Vancouver Pre-Deployment Brief - May 2024 (Web Version).pptx
 
Google Gemini An AI Revolution in Education.pptx
Google Gemini An AI Revolution in Education.pptxGoogle Gemini An AI Revolution in Education.pptx
Google Gemini An AI Revolution in Education.pptx
 
On National Teacher Day, meet the 2024-25 Kenan Fellows
On National Teacher Day, meet the 2024-25 Kenan FellowsOn National Teacher Day, meet the 2024-25 Kenan Fellows
On National Teacher Day, meet the 2024-25 Kenan Fellows
 
Spellings Wk 4 and Wk 5 for Grade 4 at CAPS
Spellings Wk 4 and Wk 5 for Grade 4 at CAPSSpellings Wk 4 and Wk 5 for Grade 4 at CAPS
Spellings Wk 4 and Wk 5 for Grade 4 at CAPS
 
Accessible Digital Futures project (20/03/2024)
Accessible Digital Futures project (20/03/2024)Accessible Digital Futures project (20/03/2024)
Accessible Digital Futures project (20/03/2024)
 
How to Manage Global Discount in Odoo 17 POS
How to Manage Global Discount in Odoo 17 POSHow to Manage Global Discount in Odoo 17 POS
How to Manage Global Discount in Odoo 17 POS
 
Unit 3 Emotional Intelligence and Spiritual Intelligence.pdf
Unit 3 Emotional Intelligence and Spiritual Intelligence.pdfUnit 3 Emotional Intelligence and Spiritual Intelligence.pdf
Unit 3 Emotional Intelligence and Spiritual Intelligence.pdf
 
Towards a code of practice for AI in AT.pptx
Towards a code of practice for AI in AT.pptxTowards a code of practice for AI in AT.pptx
Towards a code of practice for AI in AT.pptx
 
80 ĐỀ THI THỬ TUYỂN SINH TIẾNG ANH VÀO 10 SỞ GD – ĐT THÀNH PHỐ HỒ CHÍ MINH NĂ...
80 ĐỀ THI THỬ TUYỂN SINH TIẾNG ANH VÀO 10 SỞ GD – ĐT THÀNH PHỐ HỒ CHÍ MINH NĂ...80 ĐỀ THI THỬ TUYỂN SINH TIẾNG ANH VÀO 10 SỞ GD – ĐT THÀNH PHỐ HỒ CHÍ MINH NĂ...
80 ĐỀ THI THỬ TUYỂN SINH TIẾNG ANH VÀO 10 SỞ GD – ĐT THÀNH PHỐ HỒ CHÍ MINH NĂ...
 
OSCM Unit 2_Operations Processes & Systems
OSCM Unit 2_Operations Processes & SystemsOSCM Unit 2_Operations Processes & Systems
OSCM Unit 2_Operations Processes & Systems
 
How to Manage Call for Tendor in Odoo 17
How to Manage Call for Tendor in Odoo 17How to Manage Call for Tendor in Odoo 17
How to Manage Call for Tendor in Odoo 17
 
dusjagr & nano talk on open tools for agriculture research and learning
dusjagr & nano talk on open tools for agriculture research and learningdusjagr & nano talk on open tools for agriculture research and learning
dusjagr & nano talk on open tools for agriculture research and learning
 
On_Translating_a_Tamil_Poem_by_A_K_Ramanujan.pptx
On_Translating_a_Tamil_Poem_by_A_K_Ramanujan.pptxOn_Translating_a_Tamil_Poem_by_A_K_Ramanujan.pptx
On_Translating_a_Tamil_Poem_by_A_K_Ramanujan.pptx
 
Simple, Complex, and Compound Sentences Exercises.pdf
Simple, Complex, and Compound Sentences Exercises.pdfSimple, Complex, and Compound Sentences Exercises.pdf
Simple, Complex, and Compound Sentences Exercises.pdf
 
How to Create and Manage Wizard in Odoo 17
How to Create and Manage Wizard in Odoo 17How to Create and Manage Wizard in Odoo 17
How to Create and Manage Wizard in Odoo 17
 
HMCS Max Bernays Pre-Deployment Brief (May 2024).pptx
HMCS Max Bernays Pre-Deployment Brief (May 2024).pptxHMCS Max Bernays Pre-Deployment Brief (May 2024).pptx
HMCS Max Bernays Pre-Deployment Brief (May 2024).pptx
 
Jamworks pilot and AI at Jisc (20/03/2024)
Jamworks pilot and AI at Jisc (20/03/2024)Jamworks pilot and AI at Jisc (20/03/2024)
Jamworks pilot and AI at Jisc (20/03/2024)
 
Understanding Accommodations and Modifications
Understanding Accommodations and ModificationsUnderstanding Accommodations and Modifications
Understanding Accommodations and Modifications
 
How to Add New Custom Addons Path in Odoo 17
How to Add New Custom Addons Path in Odoo 17How to Add New Custom Addons Path in Odoo 17
How to Add New Custom Addons Path in Odoo 17
 

Arihant handbook biology for class 11 .pdf

  • 1.
  • 2. Sanjay Sharma ARIHANT PRAKASHAN, (SERIES) MEERUT handbook KEY NOTES TERMS DEFINITIONS FLOW CHARTS Highly Useful for Class XI & XII Students, Medical Entrances and Other Competitions Biology Supported by Kavita Agarwal Navraj Bharadwaj
  • 3. © Publisher No part of this publication may be re-produced, stored in a retrieval system or distributed in any form or by any means, electronic, mechanical, photocopying, recording, scanning, web or otherwise without the written permission of the publisher. Arihant has obtained all the information in this book from the sources believed to be reliable and true. However, Arihant or its editors or authors or illustrators don’t take any responsibility for the absolute accuracy of any information published and the damages or loss suffered there upon. Head Office Kalindi, TP Nagar, Meerut (UP) - 250002 Tele: 0121-2401479, 2512970, 4004199; Fax: 0121-2401648 For further information about the books published by Arihant log on to www.arihantbooks.com or email to info@arihantbooks.com Regd. Office ‘Ramchhaya’4577/15, Agarwal Road, Darya Ganj, New Delhi -110002 Tele: 011- 47630600, 43518550; Fax: 011- 23280316 Administrative & Production Offices Agra, Ahmedabad, Bengaluru, Bareilly, Chennai, Delhi, Guwahati, Hyderabad, Jaipur, Jhansi, Kolkata, Lucknow, Meerut, Nagpur & Pune All disputes subject to Meerut (UP) jurisdiction only. Arihant Prakashan (Series), Meerut /arihantpub /@arihantpub Arihant Publications /arihantpub Sales & Support Offices ISBN : 978-93-13196-51-8 Published by Arihant Publications (India) Ltd. All Rights Reserved
  • 4. Handbook means reference book listing brief facts on a subject. So, to facilitate the students in this we have released this Handbook of Biology. This book has been prepared to serve the special purpose of the students, to rectify any query or any concern point of a particular subject. This book will be of highly use whether students are looking for a quick revision before the board exams or just before other Medical Entrances. This handbook can even be used for revision of a subject in the time between two shift of the exams, even this handbook can be used while travelling to Examination Centre or whenever you have time, less sufficient or more. — To give confidence to the students just before they attempt important examinations. The objectives of publishing this handbook are : — To provide a focus to students to clear up their doubts about particular concepts which were not clear to them earlier. The format of this handbook has been developed particularly so that it can be carried around by the students conveniently. However, we have put our best efforts in preparing this book, but if any error or what so ever has been skipped out, we will by heart welcome your suggestions. Apart from all those who helped in the compilation of this book, a special note of thanks goes to Miss Akansha Tomar of Arihant Publications. — To support students in their revision of a subject just before an examination. Authors PREFACE
  • 5. 1. 1-6 The LivingWorld — CharacteristicsofLivingBeings — Taxonomy — Systematics — TaxonomicalAids — Biodiversity 2. 7-23 Biological Classification — Classification of Living Organisms — Kingdom–Protista — Biology : Nature and Scope — Kingdom–Fungi — Kingdom–Monera — Kingdom–Plantae — Kingdom–Animalia — Viruses andViroids CONTENTS 3. 24-42 4. 43-73 Plant Kingdom Animal Kingdom — Bryophyta — Pteridophyta — Angiospermae — Algae — Alternation of generations — Plants : Producers of Ecosystem — Gymnospermae — Phylum–Annelida — Phylum–Coelenterata(Cnidaria) — Phylum–Porifera — Phylum–Arthropoda — Phylum–Hemichordata — BasisofClassification — Phylum–Echinodermata — Phylum–Aschelminthes — Phylum–Chordata — Phylum–Mollusca — Phylum–Platyhelminthes 5. 74-103 Morphology of Flowering Plants — Seed — Flower — Fruit — Stem — Leaf — Inflorescence — Plant Morphology :An Overview 6. 104-121 Anatomy of Flowering Plants — Anatomy of Dicot and Monocot Plants — Secondary Growth in Plants — The tissues — Plant Tissue System
  • 6. 7. 122-151 Structural Organisation in Animals — Cockroach — EpithelialTissue(ByRuysch) — Tissue — NeuralTissue — ConnectiveTissue — MuscularTissue — Earthworm — Frog 8. 152-166 Cell : The Unit of Life — Components of a Cell — Cell — Cell Theory — Structure and Components of Eukaryotic Cell 9. 167-188 Biomolecules 10. 189-194 Cell Cycle and Cell Division — NucleicAcids — How to Analyse Chemical Composition? — DNA — Proteins — Lipids — Biomolecules — Carbohydrates(Saccharides) — Enzymes — RNA — Metabolites — Amitosis — CellCycle — SignificanceofCellCycle — DividingorM-phase 11. 195-206 Transport in Plants — Absorption of Water by Plants — Plant-Water Relation — Long Distance Transport of Water — Uptake and Transport of Mineral Nutrients — Upward Water Movement in a Plant — Translocation and Storage of Food in Plants (Phloem Transport) — Process Involved in Passive Transport 12. 207-214 Mineral Nutrition in Plants — Classification of Mineral Nutrients — Deficiency Symptoms of Essential Mineral Nutrients — Metabolism of Nitrogen — Hydroponics 13. 215-227 Photosynthesis in Higher Plants — Chemistry and Thermodynamics of Photosynthesis — Chloroplast : Photosynthetic Organ of Cell — Factors Affecting Photosynthesis — Photorespiration
  • 7. 14. 228-238 15. 239-248 Respiration in Plants Plant Growth and Development — Factors Affecting Respiration — Anaerobic Cellular Respiration — Cellular Respiration — Aerobic Respiration — Pentose Phosphate Pathway (PPP) — Plant Hormones/Phytohormones/ Plant Growth Regulators (PGRs) — Photoperiodism — Growth — Development — Seed Dormancy — Abscission of Plant Parts 16. 249-264 Digestion andAbsorption — DigestiveEnzymes — HumanDigestiveSystem — PhysiologyofDigestion — DisorderofDigestiveSystem — DigestiveGlands — DigestiveHormones — AlimentaryCanal 17. 265-275 Breathing and Exchange of Gases — RegulationofRespiration — ExchangeofGases — HumanRespiratorySystem — Respiration — Lungs — TransportofGases — DisordersofRespiratorySystem 18. 276-296 20. 307-329 19. 297-306 Body Fluids and Circulation Locomotion and Movement Excretory Products and Their Elimination — Body Fluids — Lymph — Blood — Circulatory System — BloodVascular System — Portal System — Human Circulatory System — Specialised Muscle Phenomena — Disorders of Muscular and Skeletal System — Movement — Muscle — Locomotion — Skeletal System — Joints — Micturition — Mechanism of Filtrate Concentration — Excretion — Human Excretory System — Excretory Products — Role of Other Organs in Excretion — Regulation of Kidney Function
  • 8. 21. 330-359 Neural Control and Coordination — Spinal Cord — Nerve Impulse — TheVisual Sense-The Eye — Human Ear-Organ of Hearing and Balance — Central Nervous System — Sense Organs — Reflex Arc — Brain — Reflex Action — Synapse — Human Neural System — BrainVentricles 22. 360-370 Chemical Coordination and Integration — Glands — Major Hormones of Human Endocrine System — Hormones — Mechanism of HormoneAction — Regulation of HormoneAction — Human Endocrine System 23. 371-375 Reproduction in Organisms — Reproduction in Plants — Reproduction in Animals — Events in Sexual Reproduction of Both Plants andAnimals 24. 376-390 Sexual Reproduction in Flowering Plants — Pollination — Fertilisation — Post-fertilisation Events — Flowers — Pre-fertilisation : Structures and Events — Development of Embryo/Embryogenesis 25. 391-414 Human Reproduction — Lactation — Embryonic Development — Male Reproductive System — Spermatogenesis — Structure of Sperm — The Menstrual Cycle — Foetal Development — Placenta — Female Reproductive System — Gametogenesis — Fertilisation — Implantation 26. 415-425 Reproductive Health — Sexually Transmitted Diseases — Assisted Reproductive Technology — Strategies to Improve Reproductive Health — Medical Termination of Pregnancy — Infertility — Detection of Foetal Disorders during Early Pregnancy — Acquired Immuno Deficiency Syndrome — Problems Related to Reproductive Health — Population Explosion
  • 9. 27. 426-449 Principles of Inheritance andVariation — Gregor Johann Mendel — Sex-Determination — Linkage — Mendel's Laws of Inheritance — Chromosomal Theory of Inheritance — Mutation — Pedigree Analysis — Heredity — Variations 28. 450-468 Molecular Basis of Inheritance — Human Genome Project — DNA Fingerprinting — Wobble Hypothesis — Regulation of Gene Expression — Genetic Code — RNA — Gene Expression — DNA — DNA as Genetic Material 29. 469-499 Evolution — Mechanism of Evolution — Mutation Theory — Origin of Life — Origin of Universe — Evidences of Evolution — Theories of Evolution — Darwinism — Human and Other Primates — Evolution of Human 30. 500-521 Human Health and Diseases — Adolescence — Autoimmunity — Drugs — Cancer — De-addiction — Acquired Immuno Deficiency Syndrome — Addiction — Complement System — Human Health — Common Diseases in Humans — Vaccination and Immunisation — Immunity and Immune System — Allergies 31. 522-537 Strategies for Enhancement in Food Production — LacCulture — AnimalHusbandry — PlantBreeding — SingleCellProtein — Apiculture/Bee-Farming — Improvement of Animals through Breeding — Pisciculture/FishFarming/Culture Fishery — Sericulture 32. 538-547 Microbes in Human Welfare — Microbes in Industrial Products — Biopesticides — Microbes in Household Products — Bioherbicides — Microbes in Sewage Treatment — Bioinsecticides
  • 10. 33. 548-561 Biotechnology : Principles and Processes — Genetic Engineering/Recombinant DNA Technology — Downstream Processing — Bioreactors — Principle of Biotechnology — Gel Electrophoresis — Tools of rDNA Technology 36. 586-603 35. 575-585 Ecosystem Organisms and Population — Ecosystem — Food Web — Features of Ecosystem — Ecosystem: Structure and Characteristics — Components of Ecosystem — Food Chain — Ecosystem Services — Population and Community — Organism and its Environment — Responses to Abiotic Factors — Adaptations — Characteristics of Population 34. 562-574 Biotechnology and ItsApplications — Applications of Biotechnology in Plant Tissue Culture — Applications of Biotechnology in Medicine — Types of Biotechnology — Applications of Biotechnology in Industry and Environment 37. 604-617 Biodiversity and Conservation — IUCN and Red List Categories — Levels of Biodiversity — Importance of Biodiversity — Biodiversity Conservation — Loss of Biodiversity — Patterns of Biodiversity 38. 618-639 Environmental Issues — Ozone Layer Depletion — Global Warming — Greenhouse Effect — Acid Rain — Degradation by Improper Resource Utilisation and Maintenance — Pollution Appendix 640-644
  • 11. Life is a characteristic quality that differentiates inanimate (non-living) objects from the animate (living) forms. Characteristics of Living Beings 1 The Living World Metabolism Thermoregulation Cellular Organisation Composition and arrangement of ·cells in body. Process that allows your body to maintains its core internal temperature Reproduction Conciousness Adaptation Process of producing young ones by living things. Ability of an organism to sense its environment. Genetic mechanism of an organism to survive, thrive and reproduce by constantly enhancing itself. Heat Stroke Increase in body temperature above the normal level. Hypothermia Decrease in body temperature below the normal level. Multicellular Organisms Organisms with multiple cells of various type, , . e.g. Hydra Asexual Reproduction Does not involve the fusion of gametes or sex cells, e.g., Amoeba. Sexual Reproduction Involves the fusion of gametes, humans. e.g., Catabolism Process of breakdown of complex substances into simpler ones, respiration. e.g., Anabolism Process of formation of complex substances from simpler ones, photosynthesis. e.g., Short-term Adaptations Temporary changes to respond to changing environment, hibernation and aestivation. e.g., Long-term Adaptations Permanent changes in response to changing environment, humming birds. e.g., Irritability Ability of an organism to react against external stimuli, movement of an organism towards the light source. e.g., A series of chemical processes catalysed by enzymes, occurring within the body of living beings. Characteristics of Living Beings Unicellular Organisms Organisms having a single cell, , . e.g. Amoeba Growth Living organisms grow with increase in mass and number of individuals/cells.
  • 12. Biodiversity It is the degree of variability among living organisms. It includes all the varieties of plants and animals. It encompasses all the ecological complexes (in which the diversity occurs), ecosystem, community diversity, species diversity and genetic diversity. It comprises all the millions of species and the genetic differences between them. Systematics It is the study of the biodiversity. It attempts to classify the diversity of organisms on the basis of following four fields viz, identification, classification, nomenclature. 1. Identification It aims to identify the correct name and position of an organism in the already established classification system. It is done with the help of keys. Key is a list of alternate characters found in organisms. An organism can be identified easily by selecting and eliminating the characters present in the key. 2. Classification It involves the scientific grouping of identified organisms into convenient categories or taxa based on some easily observable and fundamental characters. The various categories which show hierarchical arrangement in decreasing order are Kingdom → Phylum → Class → Order → Family → Genus → Species 3. Nomenclature After classification, organisms are subjected to a format of two-word naming system called binomial nomenclature. It consists of two components, i.e., generic name and specific epithet. For example, in Mangifera indica, ‘Mangifera’ is the generic name and ‘indica’ is the specific name of mango. This system was proposed by C Linnaeus (a Swedish Botanist) in (1753) in his book Species Plantarum. Polynomial system of nomenclature is a type of naming system containing more than two words. Trinomial system is a component of polynomial system and contains three words. Third word represents the sub-species and first two-words remain the same as in binomial system. Codes of Biological Nomenclature There are five codes of nomenclature which help to avoid errors, duplication and ambiguity in scientific names. 2 Handbook of Biology
  • 13. The Living World 3 These codes are as follows ICBN International Code of Botanical Nomenclature ICZN International Code of Zoological Nomenclature ICVN International Code of Viral Nomenclature ICNB International Code for Nomenclature of Bacteria ICNCP International Code for Nomenclature for Cultivated Plants Types of Specification in Nomenclature The ICBN recognises following several types are given below Taxonomy It deals with the principles and procedures of identification, nomenclature and classification of organisms. It reflects the natural and phylogenetic relationships among organisms. It also provides the details of external and internal structures, cellular structure and ecological information of organisms. The term taxonomy was coined by AP de Candolle, 1813. Various Branches of Taxonomy Taxonomic Field Basis Alpha ( ) α Taxonomy Morphological traits Artificial Taxonomy Habit and habitat of organisms Natural Taxonomy Natural similarities among organisms Chemotaxonomy Presence or absence of chemicals in cells or tissues Cytotaxonomy Cytological studies Numerical or Phenetic Taxonomy Number of shared characters of various organisms Phylogenetic or Omega ( ) ω Taxonomy Based on phylogenetic relationships Neotype Holotype Lectotype Isotype Paratype Specimens described along with the holotype. New nomenclature type when the holotype is not available. Prototype specimen from which description of a new species is established. Specimen selected from original material when there is no holotype. It is the same as holotype. Syntype Any of the two or more specimens cited by an author when there is no holotype. Specification in Nomenclature
  • 14. Classical Taxonomy It is also known as old taxonomy. In classical taxonomy, species is the basic unit and it can be described on the basis of one or few preserved specimens. Organisms are classified on the basis of some limited features. Modern Taxonomy/New Systematics The concept of modern taxonomy was given by Julian Huxley (1940). According to it, species are dynamic and ever-changing entity. Studies of organisms are done on a huge number of variations. It includes cytotaxonomy, numerical taxonomy, chemotaxonomy, etc. Taxonomic Categories Classification is not a single step process. It involves hierarchy of steps in which each step represents a rank or category. Since, the category is a part of overall taxonomic arrangement, it is called the taxonomic category. The taxonomic categories, which are always used in hierarchical classification of organisms are called obligate categories. The sub-categories like sub-species, sub-class, sub-family, etc., which facilitate more sound and scientific placement of various taxa are called intermediate categories. Arrangement of taxonomic categories in a descending order during the classification of an organism is called taxonomic hierarchy. It was first introduced by Linnaeus (1751) and hence, it is also known as Linnaean Hierarchy. 4 Handbook of Biology Taxonomic Categories For Plants For Animals Kingdom Kingdom Phylum Division Class Class Order Order Family Family Genus Genus Species Species Taxonomic categories showing hierarchical arrangement in ascending order
  • 15. Taxon represents the rank of each category and referred to as a unit of classification. The term ‘Taxon’ was first introduced by ICBN during 1956. According to Mayr (1964), taxon is a group of any rank that is sufficiently distinct to be worthy of being assigned a definite category. In simple words, taxon refers to a group of similar, genetically related individuals having certain characters distinct from those of other groups. (i) Kingdom It is the highest category in taxonomy. A kingdom includes all the organisms which share a set of distinguished characters. (ii) Phylum or Division (Cuvier, Eichler) It is a taxonomic category higher than class and lower in rank to kingdom. The term ‘Phylum’ is used for animals, while ‘Division’ is commonly employed for plants. It consists of more than one classes having some similar correlated characters. (iii) Class (Linnaeus) It is a major category, which includes related orders. (iv) Order (Linnaeus) It is a group of one or more related families that possess some similar correlated characters, which are lesser in number as compared to a family or genera. (v) Family (John Ray) It is a group of related genera with less number of similarities as compared to genus and species. All the genera of a family have some common or correlated features. They are separable from genera of a related family by important differences in both vegetative and reproductive features. (vi) Genus (Term given by John Ray) It comprises a group of related species, which has more characters common in comparison to species of other genera. In other words, genera are the aggregates of closely related species. (vii) Species Taxonomic studies consider a group of individual organisms with fundamental similarities as a species (John Ray). It is the lowest or basic taxonomic category, which consists of one or more individuals of a population. The Living World 5
  • 16. Taxonomical Aids They include techniques, procedures and stored information that are useful in identification and classification of organisms. Some of the taxonomical aids are as follows Importance of Taxonomical Aids l These aids help to store and preserve the information as well as the specimens. The collection of actual specimens of plant and animal species is essential and is the prime source of taxonomic studies. l These are also essential for training in systematics which is used for the classification of an organism. Hence, taxonomic aids facilitate identification, naming and classification of organisms using actual specimens collected from the fields and preserved as referrals in the form of herbaria, museums, etc. 6 Handbook of Biology Herbarium Storehouse of collected plant specimens that are dried, pressed and preserved on sheets. Manuals and Catalogues Provide information for identification of names of species found in an area. Museums Place for the collection of preserved plants and animal specimens. Monographs Contain information on any one taxon. Keys Used for identification of plants and animals based on their similarities and dissimilarities. Botanical and Zoological Parks Contain the living collection of plants and animals in the conditions similar to their natural habitat. Taxonomical Aids
  • 17. 2 Biological Classification Biology : Nature and Scope Biology (L. bios – life; logos – knowledge) is the branch of science, which deals with the study of living organisms and their life processes. Aristotle is called the Father of Biology, but the term ‘Biology’ was first coined by Lamarck and Treviranus in 1802. It has two main branches, i e . ., Botany (study of plants) and Zoology (study of animals). l Father of Botany Theophrastus l Father of Zoology Aristotle Classification of Living Organisms Classification is an arrangement of living organisms according to their common characteristics and placing the group within taxonomic hierarchy. The branch of science which deals with description, nomenclature, identification and classification of organisms is called taxonomy. Some major branches of taxonomy are (i) Numerical taxonomy It is based on all observable characteristics. Number and codes are assigned to characters and data is processed through computers. (ii) Cytotaxonomy In this taxonomy, the detailed cytological information is used to categorise organisms. (iii) Chemotaxonomy The chemical constituents are taken as the basis for classification of organisms.
  • 18. On the basis of reference criteria, the classification of living organisms can be of three types 1. Artificial or Prior Classification In this system of classification one or very few characters are considered as the key feature of classification. This classification system never throws light on affinities or relationships between the organisms. 2. Natural or Phenetic Classification The classification system in which organisms are classified on the basis of their permanent vegetative characters. In this classification system, the grouping of heterogenous groups (unrelated) of organisms is avoided. 3. Cladistic or Phylogenetic Classification This classification may be monophyletic (i e . ., one ancestry), polyphyletic (i e . . the organism derived from two ancestors) and paraphyletic (i e . ., the organism does not include all the descendents of common ancestor). Cladistics is a method of classification of organisms based upon their genetic and ancestral relationships, which are more scientific and natural. The most accepted, five kingdom system of classification of living organisms was proposed by RH Whittaker. These five kingdoms are Monera, Protista, Fungi, Animalia and Plantae. Other Classification Systems l Two kingdom system–Carolus Linnaeus (Animalia and Plantae). Merits Photosynthetic organisms were included into plant kingdom and non-photosynthetic organisms were included into animal kingdom. Demerits Some organisms do not fall naturally either into plant or animal kingdom or share characteristics of both. l Three kingdom system–Ernst Haeckel (Protista, Animalia and Plantae). Merits Created a third kingdom which includes unicellular eukaryotic microorganisms and some multicellular organisms. Demerits Monerans were not placed correctly. 8 Handbook of Biology Artificial Prior Classification or Classification of Living Organisms Natural Phenetic Classification or Phylogenetic Cladistic Classification or
  • 19. l Four kingdom system–Copeland (Monera, Protista, Animalia and Plantae). Merits Monerans were placed separately along with other kingdoms. Demerits Monerans were not subdivided in Archaebacteria and Eubacteria. l Six kingdom system–Carl Woese (Archaebacteria, Eubacteria, Protista, Fungi, Animalia and Plantae). Merits Archaebacteria and Eubacteria were separately placed. A. Kingdom–Monera (Prokaryotic, Unicellular Organisms) It includes all prokaryotes such as bacteria, archaebacteria, mycoplasma, actinomycetes, cyanobacteria and rickettsia. 1. Bacteria These unicellular, prokaryotic organisms contain cell wall (feature of plant cells only). These are approximately 4000 species of bacteria, with cosmopolitan occurrence. Bacteria can be regarded both friends and foes on the basis of interaction with human beings. An average weight human (~ 70 kg) has about 2.5 kg of bacteria in the form of gut microflora to supplement the proper digestion and other metabolic functions. Details to bacteria can be visualised in a nutshell as Biological Classification 9 Non-motile Bacteria On the basis of staining behaviour Cocci (rounded) On the basis of structure Bacilli (capsule) On the basis of nutrition Spirillum (spiral) Vibrio (comma-like) Methanogens Halophiles Eubacteria (true bacteria) Gram-Negative Bacteria Thermoacidophiles (methane producing bacteria) (salty/marine bacteria) (present in acidic sulphur springs) Archaebacteria Gram-Positive Bacteria Autotrophic Heterotrophic Photosynthetic bacteria Saprophytic Purple-sulphur bacteria Symbiotic Parasitic • • • • • Motile (primitive bacteria)
  • 20. (i) Archaebacteria These are the group of most primitive prokaryotes. They have a cell wall, made up of protein and non-cellulosic polysaccharides. The presence of 16 srRNA, makes them unique and helps in placing in a separate domain called archaea between bacteria and eukarya. Archaebacteria can live under extreme hostile conditions like salt pans, salt marshes and hot sulphur springs. They are also known as living fossils, because they represent the earliest form of life on earth. Archaebacteria can be used for (a) Experimentation for absorption of solar radiation. (b) Production of gobar gas from dung and sewage. (c) Fermentation of cellulose in ruminants. (ii) Eubacteria Eubacteria are ‘true bacteria’ which lack nucleus and membrane bound organalles like mitochondria, chloroplasts, etc. Eubacteria are usually divided into five phylums– Spirochetes, Chlamydias, Gram- positive bacteria, Cyanobacteria and Proteobacteria. The structural detail of a typical eubacterial cell is given as follows 10 Handbook of Biology Capsule pathogens desiccation surface It is made up of gelatinous polysaccharide and polypeptide. It protects the bacteria, from and . It helps in adherance to any . Cytoplasm It contains 80% water, protein, carbohydrate, lipid, organic ions, etc. Ribosomes 70 S type of ribosomes, consists of RNA and proteins. r Cell Wall It is rigid due to the presence of murein. Cell wall contains Mg ions which bind to teichoic acid. This binding protects the bacteria from thermal injuries. 2+ Nuclear Area (Nucleoid) It is amorphous lobular mass of fibrillar chromatin type material which occupies 10-20% area of cell. Plasmid Small, circular, self-replicating extrachromosomal DNA, having few genes. Flagellum filament hook basal body Long, filamentous appendage consisting of , and . It is rotatory in function and contains flagellin protein. Inclusions glycogen starch lipid sulphur granules These are reserve food deposits found in prokaryotic and eukaryotic cells. These may be of , , and . Plasma Membrane Its structure and functions are similar to eukaryotic plasma membrane. It is also the site of some respiratory enzymes. Fimbriae pilin. These are short, filamentous structures composed of protein, These are evenly distributed and used for attachment rather than motility. Mesosome Complex localised infolding of membrane which serves as respiratory organ, ., centre of respiration. i.e Detailed structure of a bacterium
  • 21. Nutrition in Bacteria The process of acquiring energy and nutrients., is called nutrition. On the basis of mode of nutrition, bacteria are of two types– autotrophic and heterotrophic. About 1% bacteria show autotrophic mode of nutrition and the rest are of heterotrophic habit. Chemosynthetic bacteria oxidise various inorganic substances such as nitrates, nitrites and ammonia and use the released energy for their ATP production. Autotrophic (i.e., photosynthetic) bacteria and heterotrophic bacteria with their related details are mentioned in following tables. Some Photosynthetic Bacteria Group Main Habitats Cell Wall Representatives Prochlorobacteria Live in tissues of marine invertebrates. Gram-negative Prochloron Purple or green bacteria Generally anaerobic and reside on sediments of lakes and ponds. Gram-negative Rhodospirillum and Chlorobium Some Heterotrophic Bacteria Group Main Habitats Cell Wall Representatives Spirochetes Aquatic habitats, parasites of animals Gram-negative Spirochaeta and Treponema. Aerobic rods and cocci Soil, aquatic habitats, parasites of animals and plants Gram-negative Pseudomonas, Neisseria, Nitrobacter, Azotobacter and Agrobacterium Facultative anaerobic rods (enterobacteria) Soil, plants, animal gut Gram-negative Salmonella, Shigella, Proteus, Escherichia and Photobacterium Sulphur and sulphate reducing bacteria Anaerobic muds, sediments (as in bogs, marshes) Gram-negative Desulfovibrio Myxobacteria Decaying plant and animal matter, bark of living trees Gram-negative Myxococcus and Chondromyces Biological Classification 11
  • 22. Group Main Habitats Cell Wall Representatives Mycoplasmas Parasites of plants and animals Cell wall absent Mycoplasma Gram-positive cocci Soil, skin and mucous membranes of animals Gram-positive Staphylococcus and Streptococcus Endospore-forming rods and cocci Soil; animal gut Gram-positive Bacillus and Clostridium Non-sporulating rods Fermenting plant and animal material, human oral cavity, gut, vaginal tract Gram-positive Lactobacillus and Listeria Chemoautotrophes Soil, aquatic habitat Gram-negative Halothiobacillus and Acidothiobacillus Respiration in Bacteria Respiration occurs in the plasma membrane of bacteria. Glucose is broken down into carbon dioxide and water using oxygen in aerobic cellular respiration and other molecules such as nitrate (NO ) 3 in anaerobic cellular respiration. Reproduction in Bacteria Bacteria reproduce asexually and sexually both. Asexual Methods Asexually, bacteria reproduce by following methods l Fission Bacteria divide both laterally and longitudinally. l Budding Vegetative outgrowths result into new organisms after maturity. l Spore formation Non-motile spores like conidia, oidia and endospores are formed. Sexual Methods Although sexes are not differentiated in bacteria, following methods of genetic recombination are categorised under sexual reproduction in bacteria. l Transformation F Griffith (1928), Genetic material of one bacteria is transferred to other through conjugation tube. 12 Handbook of Biology
  • 23. l Conjugation Lederberg and Tatum (1946), Transfer of genetic material occurs through sex pili. l Transduction Zinder and Lederberg (1952), Transfer of genetic material occurs by bacteriophage. Economic Importance of Bacteria Economically, some bacteria are useful in producing various useful substances like curd, cheese, antibiotics and vinegar, etc. While other bacteria cause several chronic diseases in humans, plants and other animals, etc. Other Monerans These are as follows 1. Mycoplasma l It was discovered by Nocard and Roux in 1898. These are cell wall less, aerobic and non-motile organisms. Due to the absence of cell wall and pleomorphic nature, they are commonly called as jokers of living world. l The mycoplasmas are also known as Pleuro Pneumonia Like Organisms (PPLO). These are the smallest living cells, yet discovered, can survive without oxygen and are typically about 0.1 µm in diameter. 2. Actinomycetes l The members of a heterogeneous group of Gram-positive, are generally anaerobic bacteria noted for a filamentous and branching growth pattern. It results in most forms in an extensive colony or mycelium. Biological Classification 13 Lipoprotein membrane (3 layers) Ribosomes DNA Soluble RNA Structure of Mycoplasma
  • 24. l Morphologically, they resemble fungi because of their elongated cells that branch into filaments or hyphae. During the process of composting, mainly thermophilic and thermotolerent Actinomyces are responsible for the decomposition of the organic matter at elevated temperature. l Generally, Actinomycetes grow on fresh substrates more slowly than other bacteria and fungi. During the composting process, the Actinomycetes degrade natural substances such as chitin or cellulose. l Natural habitats of thermophilic Actinomycetes are silos, corn mills, air conditioning systems and closed stables. Some Actinomycetes are found responsible for allergic symptoms in the respiratory tract, e.g., Extrinsic Allergic Alveolitis (EAA). 3. Cyanobacteria/Blue-Green Algae (BGA) l They are Gram-negative photosynthetic prokaryotes which perform oxygenic photosynthesis. These can live in both freshwater and marine habitats and are responsible for ‘blooms’ in polluted water (eutrophication). l They have photosynthetic pigments, chlorophyll-a, carotenoids and phycobilins and food is stored in the form of cyanophycean starch, lipid globule and protein granules. l Cyanobacteria have cell wall formed of peptidoglycan, naked DNA, 70S ribosomes and the absence of membrane bound organelles like endoplasmic reticulum, mitochondria, Golgi bodies, etc. l The red sea is named after the colouration provided by red coloured cyanobacteria i.e., Trichodesmium erythraeum. l Cyanobacteria can fix atmospheric nitrogen through a specific structure called heterocyst. These are modified cells in which photosystem-II is absent hence, non-cyclic photophosphorylation does not take place. Nitrogen-fixation is performed through enzyme nitrogenase, present in it. 4. Rickettsia l These are small, aerobic and Gram-negative bacteria. They belong to phylum–Proteobacteria, which are capable of growing in low level of nutrients and have long generation time relative to other Gram-negative bacteria. l Rocky Mountain Spotted Fever (RMSF) is a tick borne human disease caused by Rickettsia rickettsii, an obligate, intracellular bacteria. 14 Handbook of Biology
  • 25. B. Kingdom–Protista (Eukaryotic, Unicellular Organisms) It includes three broad groups, explained in the following flow chart In the view of evolution, the kingdom–Protista acts as a connecting link between the prokaryotic kingdom–Monera and multicellular kingdoms like Fungi, Plantae and Animalia. The term ‘Protista’ was given by German biologist, Ernst Haeckel in 1866. The group Protista shows following characteristics in common (i) These are mostly aquatic. (ii) Eukaryotic cell of protists possess well-defined nucleus. (iii) Membrane bound organelles present. (iv) Protists reproduce both asexually and sexually by a process involving cell fusion and zygote formation. (v) They may be autotrophic and heterotrophic (i.e., parasitic). The detailed descriptions of protistan groups are as follows Plant-like Protists (Photosynthetic) These can be 1. Dinoflagellates The group of 1000 species of photosynthetic protists, belongs to the division–Pyrophyta and class–Dinophyceae. They are unicellular, motile and biflagellate, golden-brown coloured protists. They form the important components of phytoplanktons. Their macronuclei possess condensed chromosomes, even in interphase, called as mesokaryon (Dodge; 1966). Sometimes they exhibit the phenomenon of bioluminescence. Biological Classification 15 Kingdom–Protista Animal-like Protists Euglenophyta (euglenoids flagellates) Ciliated Protozoans Fungi-like Protists Pyrophyta (dinoflagellates) Amoeboid Protozoans Acrasiomycota Plant-like Protists Myxomycota (acellular slime moulds) (cellular slime moulds) (photosynthetic protists) (slime moulds) (protozoans) Chrysophyta (diatoms) Flagellated Protozoans Subphyla Sporozoans Subphyla Subphyla @unacademyplusdiscounts
  • 26. 2. Chrysophytes These include diatoms and desmids. Diatoms are mostly aquatic and sometimes present in moist terrestrial habitat. They are very good pollution indicator. The diatoms do not decay easily as their body is covered by siliceous shell. They pile up at the bottom of water body and form diatomite or diatomaceous earth (can be used as fuel after mining). 3. Euglenoids These are Euglena like unicellular flagellates found mostly in stagnant freshwater. Instead of a cell wall, they have a protein rich layer called pellicle, which makes their body flexible. They have two types of flagella (i) Long Whiplash (ii) Short Tinsel The food is stored in proteinaceous granules called pyrenoids. Photosynthetic euglenoids, behave like heterotrophs in dark, this mode of nutrition is called mixotrophic. The chief member of this group, i.e., Euglena is regarded as connecting link between animals and plants. Fungi-Like Protists (Slime Moulds) They possess the characters of both animals and fungi therefore, combinedly called as fungus-animals. They show saprophytic food habit and consume organic matter. Under suitable conditions, they form Plasmodium. On the basis of occurrence of Plasmodium, these are of two types (i) Acellular/Plasmodial slime moulds, e.g., Physarum, Fuligo septica, etc. (ii) Cellular slime moulds, e.g., Dictyostelium, Polysphondylium,etc. Animal-Like Protists (Protozoans) The most primitive relatives of animals, protozoans are heterotrophic (predator or parasitic) organisms, divided into four major groups (i) Amoeboid protozoans They live in freshwater, moist soil and salt water as parasite. They move with the help of pseudopodia as in Amoeba. Other members of this group are Entamoeba histolytica and E. gingivalis cause various digestive and oral diseases when engulfed through polluted water. 16 Handbook of Biology
  • 27. (ii) Flagellated protozoans They are either free-living or parasitic in nature. Chief members are (a) Trypanosoma sp.–carried by tse-tse fly and causes African sleeping sickness. (b) Leishmania sp. carried by sand fly and causes kala-azar or dum-dum fever. (c) Giardia sp. causes giardiasis. (d) Trichomonas vaginalis causes leucorrhoea. (iii) Ciliated protozoans They are aquatic and move actively due to the presence of cilia. They show nuclear dimorphism (macro and micronucleus), e.g., Paramecium, etc. (a) Macronucleus/Vegetative nucleus Controls metabolic activities and growth. (b) Micronucleus/ReproductivenucleusControls reproduction. (iv) Sporozoans They have an infectious, spore-like stage in their life cycle. All are endoparasites. Locomotory organs are cilia, flagella and pseudopodia, e.g., Plasmodium, Monocystis, etc. C. Kingdom–Fungi (Eukaryotic, Heterotrophic Organisms) Fungi are a group of eukaryotic, achlorophyllous, non-photosynthetic and heterotrophic organisms. The basic features of fungi include (i) Fungi lack chlorophyll, hence they are heterotrophic. (ii) They cannot ingest solid food, but absorb it after digestion. The digestive enzymes are secreted on food, then they (fungi) absorb it. (iii) On the basis of food sources, they may be saprophyte or parasites. Cell wall in fungi is made up of nitrogen containing polysaccharides, chitin. Reserved food material is glycogen or oil. Along with certain bacteria, saprotrophic fungi function as the main decomposers of organic remains. With the exception of yeasts (unicellular, fungi and filamentous), fungi bodies consist of long, slender, thread-like structures called hyphae. Mycelium is the network of hyphae. Some are called coenocytic hyphae (continuous tubes filled with multinucleated cytoplasm) and others have cross walls (septae) in their hyphae. Cell walls of fungi are composed of chitin and polysaccharides. Biological Classification 17
  • 28. Classification of Fungi (Martin; 1961) Reproduction in Fungi Three types of reproduction occur in fungi 18 Handbook of Biology Reproduction Vegetative Asexual Sexual Fragmentation Zoospore Conidia Planogametic copulation Budding Sporangiospore (Phycomycetes) Ascospore (Ascomycetes) Gametangial contact Fission Chlamydospore Basidiospore (Basidiomycetes) Gametangial copulation Sclerotia Oidia Binucleate spore Spermatogamy Rhizomorphs Somatogamy When a vegetative structure after separation produces new individual, it is called vegetative reproduction. It occurs by following processes During asexual reproduction, several mononucleate and binucleate spores are produced which later germinate into new individuals. It occurs by following methods In sexual reproduction, the fusion of compatible nuclei takes place. It involves three steps, plasmogamy, karyogamy and meiosis. It occurs by following methods Fungi Myxomycetes (body as amoeboid naked protoplast) Eumycetes (unicellular, multicellular, filamentous) Phycomycetes (mycelium aseptate and multinucleate) Ascomycetes (mycelium septate) Deuteromycetes (mycelium septate) Basidiomycetes (septate) e.g., Allomyces Puccinia and , etc. l l Members are found in aquatic habitats; decaying wood in damp places. Reproduce asexually by zoospores or aplanospores. l l l Known as sac fungi, mostly multicellular ( ) or rarely unicellular (yeast). Asexual spores are conidia produced on conidiophores. Sexual spores are ascospores produced on asci. Penicillium e.g., Albugo, etc. l l Known as imperfect fungi. Deuteromycetes reproduce only by asexual spores, conidia. e.g., , , etc. Synchytrium Aspergillus e.g.,Agaricus, etc l l Grow in soil, on logs and in living plant bodies. Reproduce vegetatively by fragmentation, sex organs are absent.
  • 29. Life Cycles of Some Fungi These can be described as follows (i) Life Cycle of Rhizopus The structural representation (sexual and asexual) of life cycle of Rhizopus is as follows Biological Classification 19 Vegetative Reproduction Fragmentation Oidia Sporangium Azygospore Meiosis Rhizopus mycelia Germ spores (+ or –) Germ sporangium Promycelium Fertilisation Diplophase (2 ) n Zygospore Haplophase ( ) n Gametangium Progametangium Progametangium(–) Sexual Reproduction Gametangium (–) Coenogamete (–) (+) + Chlamydospore Asexual Reproduction Coenogamete (+) Life cycle of Rhizopus
  • 30. (ii) Life Cycle of Yeast The diagrammatic representation of sexual cycle of Saccharomyces cerevisiae is as follows Heterothallism The phenomenon of having two genetically different and compatible sexual strains in two different thalli is called heterothallism. It was discovered by Blakeslee in Mucor. 20 Handbook of Biology Budding Gametangia Plasmogamy Ascospore Ascospores Germinate Mature ascus Young ascus Meiosis Ascus mother cell Large strain yeast cell Budding Bud Germination Zygote Karyogamy H a p l o p h a s e D i p l o p h a s e Dwarf strain yeast cells ( n ) ( 2 n ) D E F G H J K L A B C + + – – I Life cycle of Saccharomyces cerevisiae
  • 31. Mushroom and Fairy Rings Agaricus compestris is an edible mushroom. It is also called white button mushroom. The fruiting body of Agaricus, arises in concentric rings (called fairy rings or fungal flowers) from the mycelium present in the soil. Lichens They have composite structure and consist of two dissimilar organisms forming a symbiotic relationship between them. Lichens are formed by l Algal Part — Phycobiont — Provide food to fungi l Fungal part — Mycobiont — Provide shelter to algae Lichens are of three types on the basis of their structure (i) Crustose lichens These are point-like, flat lichens, e.g., Caloplaca. (ii) Foliose lichens These lichens have leafy structure, e.g., Hypogymnia physodes. (iii) Fruticose lichens These are branched lichen, form filamentous branching, e.g., Cladonia evansii, Usnea australis, etc. Various forms of lichens are given below Mycorrhiza It is a symbiotic association between a fungus and a plant. Plants prepare organic food and supply them to fungus and in return, fungus supplies water and mineral nutrients to plants. Biological Classification 21 Cora (foliose) Parmella (foliose) Cladonia (fruticose) Graphis (crustose) Attaching disc Fungal fructification Pendent branches Fungal fructification Usnea (fruticose) Podetia Early foliose part Forms of lichens
  • 32. D. Kingdom–Plantae (Eukaryotic, Chlorophyllous Organisms) These are chlorophyllous and embryo forming organisms. Mostly non-motile and function as the producers in ecosystem as they can fix solar energy into chemical energy through the process of photosynthesis. The cell wall in plants is cellulosic and stored food material is in the form of starch. A detailed account of plant kingdom is given in chapter 6. E. Kingdom–Animalia (Multicellular, Eukaryotic Organisms) The heterotrophic, eukaryotic organisms which are multicellular and lack cell wall, present in this kingdom. Animals have advanced level of tissue organisation, in which the division of labour is highly specific. The two main groups among animals are Non-chordata and Chordata, divided on the basis of the presence of notochord in them. A detailed account of animal kingdom is given in chapter 7. Viruses and Viroids 1. Viruses The term ‘Virus’ means poisonous fluid. The word was coined by Louis Pasteur. Viruses are very small (0.05-0.2 µm), infective, nucleoprotein particles, which can be called as living because of the presence of nucleic acid as genetic material and ability to produce their own copy-viruses. They show only some properties of living beings, otherwise they behave like non-livings. Hence, these are referred to as the connecting link between living and non-living. On the basis of nature of genetic material, the viruses are of two types (i) Adenovirus DNA containing, e.g., HIV, etc. (ii) Retrovirus RNA containing, e.g., Rous sarcoma virus, etc. On the basis of their host, the viruses can be categorised as (i) Animal virus (Zoophagineae), e.g., HIV, sarcoma, etc. (ii) Plant virus (Phytophagineae), e.g., TMV, etc. (iii) Bacterial viruses (Phagineae), e.g., T4 phage, etc. Characteristics of Viruses Characteristics of viruses are as follows Living l They can replicate. l In host body, they can synthesise protein. l They cause diseases like other living organisms. l Similar gene mutation as living organism. 22 Handbook of Biology
  • 33. Non-living l Do not have protoplasm, and do not perform metabolism. l These can be crystallised. l They do not respire. l In vitro culture is not possible. Structure of Viruses (i) Viruses are non-cellular and ultramicroscopic. (ii) Virus has two components (a) A core of nucleic acid called nucleoid. (b) A protein coat called capsid. 2. Viroids (RNA without a Capsid) TO Diener (1917) introduced the term as ‘Subviral pathogens’. Viroids are 100 times smaller than smallest virus. They are known to be infectious for plants only (no animal), e.g., potato spindle tuber caused by viroids. Virion An intact, inert, complete virus particle capable of infecting the host lying outside the host cell in cell free environment is called virion. Virusoids These are like viroids, but located inside the protein coat of a true virus. Virusoid RNA can be circular or linear. These are non-infectious as they are replicated only in their host. Prions/Slow Virus The prions are smallest, proteinaceous infectious particles, i.e., disease causing agents that can be transmitted from one animal to another. Biological Classification 23 Genetic material, DNA or RNA Core region inside capsid Capsomeres, together form capsid, a protein coat usually highly symmetrical. Envelope, only in some larger viruses. Structure of a virus (generalised)
  • 34. 3 Plant Kingdom Plants : Producers of the Ecosystem Plants are multicellular, photoautotrophic and embryo forming (excluding algae) organisms placed in kingdom–Plantae. They have cell wall, which is made up of cellulose and reserve food material in the form of starch (sometimes fat as in seeds). Plants are referred to as producers, because they have unique ability to fix solar energy in the form of chemical energy, through the process of photosynthesis. They supply the energy in ecosystem to other living organisms, hence they are referred to as producers. The plant kingdom is classified as Algae (L. Alga–sea weeds) These are eukaryotic, autotrophic (holophytic), chlorophyll containing, non-vascular thallophytes. These are characterised by the absence of embryonic stage and presence of non-jacketed gametangia. Mostly, they are of aquatic habitat (both freshwater and marine). The branch of Botany which deals with the study of algae is termed as ‘Algology or Phycology’. FE Fritsch is known as ‘Father of Algology’. (Prof. MOP Iyengar is regarded as Father of Indian Algology). Angiosperms (covered seed) Dicotyledons Gymnosperms (naked seeded plants) Monocotyledons Plant Kingdom Cryptogamae (non-flowering) Phanerogamae (flowering) Algae Thallophyta Bryophyta (these are embryophytes without vascular tissues.) Pteridophyta (these are embryo bearing plants which form seed and contain vascular tissue as well.) Liverworts Hornworts Mosses Ferns (non-embryophytes, lack seeds and vascular tissue.) (plant body is not divided into root, stem and leaves)
  • 35. Classification of Algae (FE Fritsch; 1935) Algal Class Colour Reserve Food Examples Chlorophyceae Grass green Starch Chlamydomonas and Spirogyra. Xanthophyceae Yellow-green Fat Microspora and Botrydium. Chrysophyceae Yellow-green and golden-brown Carbohydrate and leucosin Amphipleura and Chrysosphaera. Bacillariophyceae Brown and green Fat and volutin Pinnularia and Melosira. Cryptophyceae Red and green-blue Carbohydrate and starch Cryptomonas. Dinophyceae Dark yellow, brown-red Starch and oil Peridinium and Glenodinium. Chloromonadineae Bright green Fatty compounds Vaucheria and Trentonia. Euglenophyceae Grass green Paramylum Euglena and Phacus. Phaeophyceae Brown coloured Laminarin and mannitol Laminaria and Fucus. Rhodophyceae Red coloured Floridean starch Polysiphonia and Batrachospermum. Myxophyceae Blue-green Protein granules Nostoc and Anabaena. Characteristics of Algae Important characteristics of algae are given below Structure Algae may be unicellular and multicellular. 1. Unicellular It is of two types (i) Motile, e.g., Chlamydomonas, etc. (ii) Non-motile, e.g., Chlorella, etc. 2. Multicellular It is of following types (i) Colonial, e.g., Volvox, Hydrodictyon, etc. (ii) Aggregation, e.g., Tetraspora, Prasinocladus, etc. (iii) Filamentous, e.g., Ulothrix, Cladophora, etc. (iv) Pseudoparenchymatous, e.g., Nemalion, etc. (v) Siphonous, e.g., Vaucheria, etc. (vi) Parenchymatous, e.g., Ulva, Fritschiella, etc. (vii) Well-developed thallus, e.g., Chara, Sargassum, etc. Plant Kingdom 25
  • 36. Nutrition Mostly algae are autotrophic, due to the presence of chlorophyll. Some are parasitic, e.g., Cephaleuros that causes rust of tea. Reproduction Algae reproduce by (i) Vegetative methods (ii) Asexual methods (iii) Sexual methods Vegetative Reproduction Algae reproduce vegetatively by two methods (i) Fragmentation, e.g., Fucus, Chara, etc. (ii) By hormogones, e.g., Oscillatoria, Nostoc, etc. Asexual Reproduction In this process, some cells form motile or non-motile spores. After release, these spores give rise to new plants. Following spores are involved (i) By zoospore, e.g., Ulothrix, Oedogonium, etc. (ii) By aplanospore, e.g., Chlorella, etc. (iii) By hypnospore, e.g., Vaucheria, etc. (iv) By palmella stage, e.g., Chlamydomonas, Ulothrix, etc. (v) By endospore, e.g., Anabaena, Nostoc, etc. (vi) By akinete, e.g., Chara, Oedogonium, etc. Sexual Reproduction On the basis of shape, size, morphology and behaviour of gametes, the sexual reproduction is of following types 26 Handbook of Biology Isogamous (similar gametes, morphologically), e.g., Spirogyra. Anisogamous (gametes are dissimilar morphologically), sp. e.g., Chlamydomonas Oogamous (gametes are different both morphologically and physiologically), e.g.,Volvox. Sexual Reproduction
  • 37. Life Cycle of Algae Various algae show different types of life cycles. Life cycles of Spirogyra and Ulothrix are discussed here. Life cycle of Spirogyra It is a green alga of filamentous shape. The detailed life cycle is given below. Plant Kingdom 27 Aplanospore Azygospore Akinete Asexual reproduction Pyrenoids Cell wall Vegetative cell Vegetative filament Three degenerating nuclei Functional nucleus Sexual reproduction Haploid phase ( ) n Four haploid nuclei ( M e i o s i s ) Diploid phase (2 ) n Male gamete ( ) n Conjugation tube Female gamete ( ) n Zygospore (2 ) n Zygote (2 ) n S c a l a r i f o r m c o n j u g a t i o n 11 10 9 8 7 6 5 4 3 2 1 Chloroplast Cytoplasm Nucleus Life cycle of Spirogyra
  • 38. Life cycle of Ulothrix The diagrammatic representation of life cycle of Ulothrix is given below. 28 Handbook of Biology Palmella stage Akinete Hypnospore Macrozoospores Microzoospore Aplanospore Asexual reproduction Chloroplast Nucleus Vacuole Vegetative cell Gametangium Isogametes Vesicle Syngamy Quariflagellate zygospore Vegetative filament Sexual reproduction Haploid phase ( ) n 1 2 3 4 5 6 7 8 9 + – 10 11 12 Reduction division Resting 13 Zygospore (2 ) Phase (2 ) n n 14 15 Hold fast Zoospores Liberations of gametes Life cycle of Ulothrix
  • 39. Economic Importance Algae can be both useful and harmful. Several useful algal species with their uses are mentioned here Algin, Carrageenan and Agar l Algin, used as artificial fibre to control blood flow in surgery and in production of non-inflammable films, is extracted from marine brown algae. l Carrageenan, extracted from seaweeds is used in cosmetics, boot polish, ice cream, paints, etc. l Agar, extracted from Gelidium and Gracilaria is used in culture medium, biscuits for diabetic patients, etc. – Sargassum is used as food and fodder. – Laminaria, Fucus are used in extraction of iodine, bromine and potash. Harmful Algae Group of algae like Microcystis, Oscillatoria and Anabaena cause water blooms (eutrophication) and death and reduction of aquatic organisms. Bryophyta (L. Bryon–leaf-like; phyton–plant body) It is the simplest and primitive group of land plants. They are also known as amphibians of plant kingdom because of their habitat adaptability in both aquatic and terrestrial environment. They are the connecting link between algae and pteridophytes. Bryophytes Plant Kingdom 29 As Medicine As Food Ulva, Sargassum, Laminaria, Porphyra, Nostoc Laurencia. and Chlorella Nitella gives chlorellin (antibiotic), is used as mosquito repellent. In Industries Diatoms, are used in paints, cosmetics, etc. Chondrus, Polysiphonia, Gracilaria Source of Minerals Laminaria, Polysiphonia Ascophyllum and are used in extraction of minerals. In Agriculture Nostoc, Anabaena, help in nitrogen-fixation, hence used as biofertilisers. In Biological Research Algae like planktons are used as food by others and stabilise the ecosystem. Chlorella,Scenedesmus Acetabularia and are used as tools for biological research. Ecological Significance Algae Useful applications of algae
  • 40. are autotrophic, non-seeded, cryptogamic plants. The plant body is gametophytic and may be differentiated into stem, leaves and rhizoids. l Bryophytes do not have true vascular tissue (xylem and phloem), but some of them have hydroids (similar to xylem) and leptoids (similar to phloem) which help in the conduction of water and food, respectively. l The sex organs in bryophytes are multicellular, male sex organ is called antheridium and female sex organ is called archegonium. Sexual reproduction in bryophytes is mainly oogamous type. Classification of Bryophyta Reproduction in Bryophytes Bryophytes reproduce by both vegetative and sexual methods of reproduction. Vegetative Reproduction Following methods of vegetative reproduction are reported in bryophytes (i) By fragmentation The two fragments resulted by progressive death and decay of thallus, produce new thallus, e.g., Riccia. 30 Handbook of Biology Sphaerocarpales e.g.,Sphaerocarpus. Jungermaniales e.g., Porella Calobryales e.g., Calobryum. Bryophyta (sub-division) Hepaticopsida (Liverworts) Anthocerotopsida (Hornworts) Bryopsida (Mosses) Bryales e.g., Funaria Polytrichum. and Sphagnales e.g.,Sphagnum. Classes Orders Marchantiales e.g., Marchantia Riccia. and Order Anthocerotales , e.g. Anthoceros Orders l l l Plant body is thalloid or foliose. Cells have chloroplast without pyrenoids. Sporophyte simple or differentiated into foot, seta and capsule. l l l Plant body is thalloid and dorsiventrally flattened. Sex organs embedded in the thallus tissue. Cells bear large chloroplast with a conspicuous pyrenoid. l l l Primary gametophyte consists of prostate or thalloid protonema. Adult gametophyte consists of stem, spirally arranged leaves. Sex organs develop from superficial cells.
  • 41. (ii) By adventitious branches Special adventitious branches arise from the mid-ventral surface of the thallus, e.g., Riccia fluitans. (iii) By tubers Some species form perennating tubers at the apices of thallus, e.g., Riccia, Marchantia, etc. (iv) By persistent apices The underground part of thallus in soil remains living and grows into plant, e.g., Riccia, Pellia, etc. Sexual Reproduction The sex organs are highly differentiated and well-developed in bryophytes. The antherozoids or sperms (minute, slender, curved body, having two whiplash flagella) are released from antheridium and reach to archegonium through neck canal cells. The antherozoid fuses with egg cell to produce sporophytic generation. Life Cycle of Bryophytes A typical bryophyte shows following type of life cycle Plant Kingdom 31 Vegetative reproduction ( ) n Bryophyte Protonema ( ) n ( ) n Sexual Reproduction Female ( ) n Male ( ) n Spores ( ) n Meiosis (R/D) Spore mother cell (2 ) n Antheridium ( ) n Archegonium ( ) n Antherozoid ( ) n Egg ( ) n Fertilisation (syngamy) Zygote (2 ) n Embryo (2 ) n Sporogonium (2 ) n Gametophyte ( ) n Sporophyte (2 ) n Graphic representation of the life cycle of bryophyte (R/D refers to reductional division)
  • 42. Economic Importance Bryophytes have limited economic importance, they can be used in following ways (i) They help in soil formation (pedogenesis) and act as agent for biological succession. (ii) Peat from Sphagnum can be used as fuel and in preparation of ethyl alcohol. (iii) They help in protecting soil from erosion. (iv) Some bryophytes are used as fodder for cattle. (v) Due to high water retention capacity, Sphagnum can be used in preserving living materials and used in grafting of plants. Pteridophyta ( L. pteron–feather; phyton–plant) Pteridophytes are seedless, vascular cryptogams. They reproduce by means of spores and can reach to the tree-like heights (30-40 feets). General Characteristics (i) The plant body is differentiated into root, stem and leaves. (ii) The stem may be aerial or underground and is generally herbaceous, rarely solid and stout. (iii) Vascular tissues consist of xylem (without vessels) and phloem (without companion cells). (iv) Alternation of generations is found here, gametophyte is autotrophic and independent. (v) Sporangia containing leaves are called sporophylls. (vi) Antherozoids (flagellated male gametes) are formed in antheridia. (vii) Reproduction is of both vegetative and sexual types. (viii) On the basis of development of sporangia, they are of two types (a) Eusporangiate From a group of superficial initial cells. (b) Leptosporangiate From a single superficial initial cell. 32 Handbook of Biology
  • 43. Stelar System in Pteridophytes Stele is central vascular tissue surrounded by cortex. It is of two types Classification of Pteridophyta (Smith; 1955, Bold; 1955-57, Benson; 1957) Plant Kingdom 33 Division–Pteridophyta Psilophyta Lycophyta or Lepidophyta Sphenophyta or Arthrophyta Filicophyta or Pterophyta (foliage leaves are borne in transverse whorls, horse tails). e.g., (differentiated sporophytes contain strobili). (sporophyll contains sori ferns). e.g., (rootless sporophytes). Sub-division Endodermis Leaf trace Pericycle Phloem Xylem Leaf gap Pith Endodermis Pericycle Phloem Xylem Haplostele Outer endodermis Outer pericycle Outer phloem Inner pericycle Xylem Inner endodermis Leaf trace Leaf gap Xylem Phloem Pericycle Endodermis Actinostele Leaf trace Xylem Phloem Endodermis Pith Endodermis Pericycle Phloem Xylem Leaf trace Xylem in centre is surrounded by phlem e.g., Selaginella. Xylem Phloem surrounds the central pith. is outside to xylem, e.g., Pteridium. Central xylem core surrounded by phloem e.g., Rhynia Central xylem core is star-shaped phloem is patchy outer to xylem, ., e.g Lycopodium. Ectophloic Solenostele Xylem is like hollow cylinder surrounded by phloem e.g., Equisetum Amphiphloic Solenostele Hollow xylem cylinder has phloem on both outer and inner side of xylem, e.g., Marsilea Protostele Siphonostele
  • 44. Reproduction Pteridophytes reproduce by vegetative, asexual and sexual methods. Vegetative Reproduction It takes place by two methods (i) Death and decay of older tissues lead to separation of new branches, which can grow into new plants. (ii) Adventitious buds develop from petiole and later on rooting takes place and get separated. Asexual Reproduction It occurs by meiospores When pteridophytic plants get mature, the special spore bearing structures develop under the surface of pinnules. These structures are (i) Sporangium These are differentiated into capsule and the stalk. Capsule has a single layer of thick wall, which consists of specialised cell along with the normal wall cells. (ii) Spores These are minute, bilateral bodies of brown colour. The spore coat is two layered, i.e., thick exine and thin intine. Sexual Reproduction It is of advanced type, in which the multicellular sex organs (i.e., antheridia and archegonia) are borne on the underside of prothallus. The mucilaginous substance oozes out from archegonia, which contains malic acid. After diffusing into water, it attracts antherozoids through chemotaxis. The male nucleus fuses with the egg nucleus and forms zygote. 34 Handbook of Biology
  • 45. Life Cycle of Pteridophytes Most pteridophytic plants show similar type of life cycle. Which is diagrammatically represented below. Heterospory in Pteridophytes In heterosporous plants, a sporophyte produces two types of sporangia–micro and megasporangia. Microsporangia contain Microspore Mother Cell (MMC) each of which undergoes meiosis and produces microspores. Megasporangia contain megaspore mother cell, which after going through meiosis, produces megaspores. Microspore Microgametophyte germinate (possess an → theridia) Megaspore Megagametophyte germinate (possess arch → egonia) Plant Kingdom 35 Circinate leaf Sori Leaflet Roots with diarch condition of xylem Lower epidermis Sporangia (stalked) Upper epidermis Rhizoids Apicol Notch Germinating spore Apical notch Archegonium Antheridia Rhizoids Prothallus with archegonia and antheridia Egg Neck Archegonium A single antherozoids Cilia Antherozoids Antheridia Rhizoids Prothallus with autotrophic nutrition First leaf Cushion 2n n G am etophytic phase Sporophytic plant Sporophytic phase Rhizome with mesarch xylem Sporangium Stomium Spores Part of sporophyll with sori Covering by indusium Stalk Strobilus Mesophyll Placenta Life cycle of Dryopteris
  • 46. The differentiation between male and female gametophytes ensures cross fertilisation. This set of conditions occurs in Marsiliaceae and Salviniaceae. Economic Importance Pteridophytes are economically important group of plants. Some of them are (i) Pteridophytes are used in horticulture, since they resist wilting so can be used in cut flower arrangements. (ii) Some ferns are used in handicrafts and basketery. (iii) Pteridium leaves are used in making green dyes. (iv) Club mosses are used for making industrial lubricant since their spores contain non-volatile oils. These spores are also used as fingerprint powder in forensic investigation. (v) Some pteridophytes are used as biofertiliser (Azolla) due to their nitrogen-fixing ability. (vi) Some pteridophytes are eaten as food. Gymnospermae (L. gymnos – naked; sperma – seed) Gymnosperms are naked seeded plants, which evolved earlier than the flowering plants. They have their seeds exposed on the megasporophylls, i.e., carpels. Probably, they are the first surviving seed plants (evolved during Jurassic period). General Characteristics (i) Plants are sporophytic, differentiated into root, stem and leaves. (ii) Always heterosporous, i.e., contains two types of spores (one spore (microspore) produces male gametophyte and other (megaspore) produces female gametophyte after germination). (iii) Root system is well-developed, i.e., tap root system, some have coralloid roots (e.g., Cycas). (iv) Form various structures through symbiotic relationships, i.e., coralloid root (with algae) and mycorrhizae (with fungi). (v) Leaves are dimorphic. They are of two types (a) Foliage leaves Green, simple, needle-shaped and pinnately compound. (b) Scaly leaves Minute and deciduous. (vi) Flowers are unisexual, simple, reduced and naked, i.e., without perianth (except Gnetum). 36 Handbook of Biology
  • 47. Classification of Gymnospermae Classification of gymnosperms was described by A Arnold (1948) and modified by Pilger and Melchior (1954). Reproduction Gymnosperms reproduce by both vegetative and sexual methods. Vegetative Reproduction This is done by bulbils, which commonly arise on trunk. These bulbils get separated from plants and germinate into new plants. Sexual Reproduction The life cycle of gymnosperms is also characterised by alternation of generations. The green leafy part of the plant is the sporophyte while, the cones contain the male and female gametophytes. Upon landing on the female cone, the tube cell of the pollen forms the pollen tube, through which the generative cells migrate towards the female gametophyte. The generative cells split into two sperm nuclei, one of which fuses with the egg, while the other degenerates. After fertilisation of the egg, the diploid zygote is formed, which divides by mitosis to form embryo. The seed is covered by a seed coat, which is derived from the female sporophyte. No fruit formation takes place as gymnosperms do not have true seed covering. Life Cycle of Gymnosperms The gymnosperms are higher plants with advanced life cycle. Plant Kingdom 37 Division–Gymnospermae Cycadopsida [monoxylic wood, large frond (a type of leaf) and bipinnately compound leaves] and e.g., Cycas Zamia. Coniferopsida (large tree of sporophytic nature, produce cones in reproductive phase) and e.g., Pinus Cordaites. Gnetopsida (include both extinct and extant genera) and e.g., Gnetum Ephedra.
  • 48. 38 Handbook of Biology The descriptive account of life cycle of both Cycas and Pinus are as follows Life Cycle of Cycas Life Cycle of Pinus Male plant Staminate cone Microsporophyll Microsporangium (pollen sac) Microspore mother cell Microspore (pollen grain) Microgametophyte Body cell Male gamete (antherozoid) Oospore (zygote) Development of embryo Seed Female plant Megasporophyll Megasporangium (ovule) Megaspore mother cell Megaspore Megagametophyte (endosperm) Archegonium Female gamete (oosphere) Sporophyte (2 ) n Syngamy Gametophyte ( ) n Meiosis G erm ination Germination Cycas : Topographical representation of life cycle Female strobilus Megasporophylls Megasporangia (ovules) Megaspore mother cells Meiosis Megaspore Embryo (within a seed) Oospore Fertilisation (siphonogamous) Archegonia Oosphere (female gamete) Female prothallus (endosperm) Pinus tree Male strobilus Microsporophylls Microsporangia (pollen sacs) Microspore mother cells Meiosis Microspores (pollen grains shed) Male prothallus (vestigial) Body cell Male gamete (Monoecious) Diploid (2 ) n Haploid ( ) n Pinus : Topographical representation of life cycle
  • 49. Economic Importance Angiospermae (Gk. Angion–vessel; sperma–seed) Angiosperms constitute a distinct group of flowering plants, which form covered seeds. With about 2,50,000 species, it can be regarded as the most successful group of plants. They arose in middle of Cretaceous period. General Characteristics (i) Angiosperms range from microscopic Wolffia to the largest tree such as Eucalyptus. (ii) The pollen grains and ovules develop in their flowers and the seeds are formed within the fruits. (iii) Nutritionally, they may be autotrophic (wheat, corn, etc.), parasitic (Cuscuta, Santalum, etc.), saprophytic (Monotrapa, etc.) and insectivorous (Drosera, Utricularia, etc.). (iv) They may be herb, shrub and trees. (v) Their lifetimes may be ephemeral, annual, biennial and perennial. (vi) Angiosperms are adapted to various habitats, as they may be hydrophytes, xerophytes and mesophytes. (vii) A flower is a modified shoot comprising of four whorls, i e . ., sepal, petal, androecium and gynoecium. Plant Kingdom 39 • • • Food Tuber and seeds of Seeds of sp. Chilgoza from sp. Cycas. Gnetum Pinus Industrial Products • • • amber Paper from pulp of sp. Methyl alcohol, terpentine and resin from sp. The fossilised resin of is known as , used in jewellery and X-ray sheets. Pinus Pinus Pinus excelsa Medicines • • • Resin of is used to treat ulcers. Ephedrine from (treatment of asthma). Resin of is used in stomach problem and to treat gonorrhoea. C. rumphii Ephedra Pinus Furniture • • Wood of . Wood of and are also used. Pinus Ephedra Gnetum Ornamentals Almost all gymnosperms are grown for ornamentation purpose. Academic Both extinct and extant species of gymnosperms help in studying the process of evolution. Gymnosperms
  • 50. Classification of Angiosperms A natural system of classification was given by George Bentham and JD Hooker in 1862-63 in his book Genera Plantarum (3 volumes) in Latin. The outline of the above mentioned classification is as follows Some important plant families with their representative genera are as follows Ranunculaceae, Brassicaceae (e.g., mustard), Malvaceae (e g . ., gurhal), Asteraceae (e.g., sunflower), Lamiaceae (e.g., tulsi), Solanaceae (e.g., potato), Leguminosae (e.g., pea), Cucurbitaceae, Euphorbiaceae, Orchidaceae, Palmae (e.g., cashewnut), Poaceae (e.g., paddy) and Liliaceae (e.g., onion), etc. Reproduction in Angiosperms Angiosperms are plants that bear fruits and flowers. These flowers are plant’s reproductive structures. Reproduction in angiosperms (mostly sexual type) occurs when the pollen from an anther is transferred to stigma. When the ovules get fertilised, they will develop into seeds. Non-reproductive structures like petals, sepals etc. of the flowers fall off leaving only the ovary behind, which will develop into a fruit. 40 Handbook of Biology Phanerogamia (seed plants in which sex organs are evident) Dicotyledonae Gymnospermae Monocotyledonae Classes Polypetalae Gamopetalae Monochlamydeae Cycadaceae Coniferae Gnetaceae Sub-classes Sub-classes
  • 51. Economic Importance Alternation of Generations It can also be termed as ‘Patterns of life cycle’. Plants divide mostly through mitotic divisions and form different plant bodies (these may be haploid or diploid). The interconversion of the haploid and diploid plant body in alternate manner is called alternation of generations. Generally, it is of three types Plant Life Cycles (i) Haplontic Sporophytic generation is not prominent, e.g., algae, etc. Plant Kingdom 41 Gametophytic plant Germination Gametangia Meiospores Zygotic meiosis Zygote Gametes Syngamy Haploid phase ( ) n Diploid phase (2 ) n Diagrammatic outline of a haplontic life cycle Furniture Wood from angiosperms. Food Grain, cereals and fruits. Ornamental Flowering plant. Decoration material. Vegetables Industrial Paper industry. Cosmetics. Baking industries. Environment Biodiversity Air purification. Medicines Antibiotics Alkaloids Aesthetic/Sacred Several plants have sacred importance, tulsi, peepal, etc. e.g., Important food component. Protein source. • • • • • • • • • Angiosperms • • Useful applications of angiosperms
  • 52. 42 Handbook of Biology (ii) Diplontic Gametophytic generation is of very short duration, e.g., gymnosperms and angiosperms, etc. (iii) Haplo-Diplontic Both gametophytic (n) and sporophytic (2n) are free-living, independent and multicellular phases, e.g., bryophytes, pteridophytes, etc. Diploid (2 ) n Haploid ( ) n Sporophytic plant Germination Sporangium Zygote Sporogenic meiosis Syngamy Gametes Sex organs Meiospores Germination Gametophytic plant Diagrammatic outline of a haplo-diplontic life cycle Sporophytic plant Zygote Gametogenic meiosis Gametes Gametes Gametangia Germination Syngamy Diploid phase (2 ) n Haploid phase ( ) n Diagrammatic outline of a diplontic life cycle Types of Meiosis Seen in Different Life Cycles Sporic Meiosis (in diplo-haplontic life cycle), etc. e.g., Ectocarpus, Laminaria, Zygotic Meiosis (in haplontic life cycle), . e.g., Volvox, Spirogyra Gametic Meiosis (in diplontic life cycle), Diatoms, etc. e.g., Sargassum,
  • 53. 4 Animal Kingdom Kingdom Animalia is characterised by multicellular, eukaryotic animal forms. It is also known as Metazoa. It includes around 1.2 million species of animals from sponges to mammals (other than protozoans). Metazoa Mesozoa Enterozoa Radiata Bilateria Deuterostomia Parazoa Worm-like bilateral symmetry, parasitic on cephalopods and other invertebrates, Phylum–Mesozoa. e.g., Cells loosely organised, no organs, no digestive cavity, Phylum–Porifera. e.g., True tissues present, a digestive cavity present also called Eumetazoa. Bilateral symmetry, organ systems present, triploblastic, digestive tract complete. Mouth not from blastopore mesoderm develops from archenteron, Phylum–Echinodermata, Hemichordata and Chordata. e.g., Eucoelomata (Schizocoela) Contains true coelom, Phylum–Annelida, Arthropoda and Mollusca, along with , , etc. (minor phyla). e.g., Sipuncula Onychophora Divisions Sub-divisions Radial or biradial symmetry no organs, diploblastic, Phylum–Coelenterata and Ctenophora. e.g., Protostomia Mouth from blastopore, cleavage spiral and determinate. Acoelomata Contains no coelom, Phylum–Platyhelminthes. e.g., Sections Pseudocoelomata Contains pseudocoelom, Phylum–Nematoda. e.g., Infra kingdoms or branches Classification of Metazoa
  • 54. 44 Handbook of Biology Ostracodermi Cyclostomata Two classes Extinct class, e.g., Pteraspis, Contains 1-16 pairs of gill slits. Head and brain are poorly developed. Endoskeleton is cartilaginous. Two-chambered heart. Fertilisation is external and development is indirect, (lamprey), (hagfish). e.g., Petromyzon Myxine • • • • • • Phylum–Chordata Urochordata (Tunicates) Vertebrata (Craniata) Notochord is replaced by vertebral column. Notochord is present in embryonic stage only. Body is either segmented or unsegmented. Cephalochordata Three sub-phyla Notochord is restricted in the posterior part of the body (tail region). Notochord is present in larval stage only. Body is unsegmented, e.g., Herdmania. • • • • Notochord is extended in the head region. Notochord is present throughout the life. Body is segmented, e.g., Amphioxus. • • • • • Agnatha (Jawless) Gnathostomata (Bear jaws) Mouth bears jaws. Embryonic notochord is replaced in adults by a vertebral column. Paired appendages (fins or limbs) are present. Nostrils are paired. Internal ear has three semicircular canals. There are 10-12 pairs of cranial nerves. Mouth does not possess jaws. Notochord persists throughout life. Paired appendages are absent. Single nostril is present. Internal ear has two or one semicircular canals. 8-10 pairs of cranial nerves, are present. • • • • • • • Two divisions • • • • • (True coelomates with enterocoelic type of coelom) Pisces Tetrapoda Two super-classes Fins are present. Respire by gills. Do not have internal nares (except lungfish). Heart is two or three-chambered. They have internal ears. Limbs are present. Respire by lungs, gills and skin. They have internal nares. Heart is three or four-chambered. They have internal, middle and external ears (except snakes). • • • • • • • • • • Chondrichthyes (Cartilaginous fishes) Aves Amphibia Reptilia Mammalia Four classes Three classes Placodermi (Extinct) Osteichthyes (Bony fishes) Classification of Phylum Chordata
  • 55. Basis of Classification There are few fundamental common features to various animal groups, which form the basis of classification. These features are as follows 1. Level of Organisation Though, all the members of kingdom–Animalia are multicellular, yet all of them do not exhibit the same pattern of cellular organisation. Different levels of organisation are discussed below 2. Symmetry It refers to the correspondence of body parts in all major respect like size, shape, position, etc., with the parts on opposite side when divided from the central axis. Types of symmetry found in animals are (i) Radial symmetry In radial symmetry, the animal gets divided into two ‘identical halves’ when any plane passes through the central axis, e.g., coelenterates, echinoderms. (ii) Bilateral symmetry In bilateral symmetry, body is divided into two ‘identical halves’ only when a plane passes through the median longitudinal axis, e.g., annelids, arthropods, etc. 3. Germ Layers These are the groups of cells behaving as a unit during early stages of embryonic development. On the basis of number of germ layers, animals are placed in two groups, i.e., diploblastic and triploblastic. These groups are divided at the gastrulation stage. Animal Kingdom 45 Acellular or Protoplasmic Level Body consists of mass of protoplasm. All activities are performed by different cell organelles and confined within the limit of plasma membrane, Protozoa. e.g., Cellular Level Body consists of many cells which either forms an aggregate or a colony. It is of two types Cellular colony Protists and some algae. Cellular aggregate Porifera (sponges), where cells are not organised into tissue. Tissue Level Group of similar cells forms tissues which serves specific functions, coelenterates. e.g., Organ Level Some tissues join and function as a unit of a organ, Stomach (one of digestive organs) contains all tissues, Platyhelminthes. e.g., e.g., Organ-System Level Group of organs working together to forms organ system, Organs such as stomach, intestine, etc., aid in digestion and constitute digestive system, Nemathelminthes to chordates. e.g., e.g., Levels of Organisation (i) (ii)
  • 56. (i) Diploblastic Embryo is two-layered consisting an outer ectoderm and inner endoderm, e.g., Hydra, jellyfish, etc. (ii) Triploblastic Embryo is three-layered consisting of an outer ectoderm, middle mesoderm and inner endoderm, e.g., humans. 4. Coelom It is a large fluid-filled space or cavity lying between the outer body wall and inner digestive tube. 46 Handbook of Biology Types of Coelom Internal body cavity separates digestive tract from outer body wall Acoelom parenchyma There is no body cavity. Region between the ectodermal epidermis and the endodermal digestive tract is completely filled with mesoderm in the form of a spongy mass of space filling cells called Porifera, Coelenterata, Ctenophora and Platyhelminthes. e.g., . Pseudocoelom The presence of false coelom or perivisceral cavity. Coelom is not lined by mesoderm and directly connected to archenteron. Developmentally, pseudocoelom is the persistent blastocoel of blastula stage, Rotifera, Aschelminthes and Nematoda. e.g., Eucoelom or True Coelom True body cavity develops entirely lined with the mesoderm, higher invertebrates (Annelida, Echinodermata and Chordata). e.g., Schizocoel Developed as a split in the mesoderm sheet, Annelida to Arthropoda. Protostomes are schizocoelous. e.g., Enterocoel Formed from the pouches of the archenteron or primitive gut. Echinodermata and chordata. Deuterostomes are enterocoelous. e.g., Coelomate Pseudocoelomate Acoelomate Pseudocoelom Ectoderm Ectoderm Endoderm Endoderm Mesoderm Endoderm Coelom Ectoderm Digrammatic sectional view of coelom
  • 57. 5. Segmentation It is the serial repetition of similar parts along the length of an animal. It is of two types (i) Pseudosegmented (strobilisation) Body is divided into number of pseudosegments (proglottids) which are independent of each other, e.g., tapeworms. (ii) Metameric Linear repetition of body parts (somites), e.g., annelids, arthropods and chordates. 6. Notochord It is a rod-like structure present on the dorsal side of the animal body. It is derived from the embryonic mesoderm. Based on its presence and absence, animals are non-chordates (phylum–Porifera to Echinodermata) and chordates (phylum–Chordata). Major differences between Chordata and Non-Chordata are as follows Chordata Non-Chordata Bilaterally symmetrical. Asymmetrical, radially symmetrical or bilaterally symmetrical. True metamerism. Non-segmented, false segmented or true metamerically segmented. True coelomates. Acoelomate, pseudocoelomate or true coelomates. Post-anal tail usually present. It is usually absent. Triploblastic animals. Cellular, diploblastic or triploblastic animals. Alimentary canal is always ventrally placed to nerve cord. Heart is ventrally placed. It is always dorsally placed to the nerve cord. Heart is dorsal or absent. Central nervous system is hollow, dorsal and single. Central nervous system is ventral, solid and double. Pharynx is perforated by gill slits. Gill slits are absent. Phylum–Porifera Poriferans bear numerous minute pores called ostia on the body wall, which leads into a central cavity called spongocoel or paragastric cavity. The spongocoel opens to outside by osculum. Animal Kingdom 47
  • 58. Majority of poriferans (sponges) are marine and sedantry. They are diploblastic animals and contain an outer dermal layer of pinacocytes and inner gastral layer of choanocytes. Canal System (Aquiferous system) It is a system of interconnected canals through which water circulates and helps in a number of metabolic activities of a sedentary sponge. In sponges, canal system is of three types, i e . ., asconoid, syconoid and leuconoid. Different Types of Canal System Asconoid Canal System Syconoid Canal System Leuconoid Canal System Simplest type with thin walls. Complex type with thick walls. Much complex type with highly folded thick walls. Spongocoel is large and spacious. Spongocoel is narrow. Spongocoel is either reduced or absent. 48 Handbook of Biology Flagellum Collar Protoplasmic processes Microvilli Basal granule Rhizoplast Blepharoplast Nucleus Cytoplasm Flagellum (create water current) Collar microvillus (filter particles from water) Endoplasmic reticulum Nucleus Mitochondrion Food vacuole Contractile vacuole (b) (a) Choanocyte : (a) Light microscopic view (b) Electron microscopic view
  • 59. Asconoid Canal System Syconoid Canal System Leuconoid Canal System Choanocytes form the gastral layer and lines the whole spongocoel. Choanocytes are restricted in radial canals only. Choanocytes are confined in the flagellated chambers which are formed by the evagination of radial canals. Route of water is Outside water  Dermal Ostia Outside ← Osculum Spongocoel e g . ., Leucosolenia. Route of water is Outside water  Dermal  Prosopyle Incurrent canal Radial canal  Apopyle  Gastral Ostia Excurrent canal Spongocoel → Osculum Outside e.g., Grantia. Route of water is Outside water Ostia Dermal   Hypodermalspaces Incurrent canals Prosopyle   Apopyle Flagellated chambers Excurrent canal   Osculum Excurrent spaces Outside, e g . ., Plakina. Reproduction In sponges, reproduction occurs by both asexual and sexual means. (i) Asexual reproduction Mainly occurs by budding and gemmules. (ii) Sexual reproduction Occurs with the help of amoebocyte or archeocytes or sometimes through choanocytes. Classification of Porifera Animal Kingdom 49 Ostia Phylum–Porifera Calcispongiae or Calcarea Demospongiae Hyalospongiae or Hexactinellida Three classes Skeleton of calcareous spicules. Large choanocytes. Small-sized species. Skeleton of siliceous spicules. Small choanocytes. Moderately-sized species. Skeleton of spongin fibres or may be absent. Very small choanocytes. Large-sized species. • • • • • • • • •
  • 60. Common and Scientific Names of Some Members of Porifera Common Species of Porifera Scientific Name Common Species of Porifera Scientific Name Glass rope sponge Hyalonema Venus flower basket Euplectella Bath sponge Euspongia Bowl sponge Pheronema Freshwater sponge Spongilla Dead man’s finger sponge Chalina Urn sponge Scypha Boring sponge Cliona Economic Importance l They are used commercially for bathing/cleaning sponges. l They help to clean-up the ocean floor by boring into dead shells and corals releasing chemicals to break them down. Phylum–Coelenterata (Cnidaria) Coelenterates are the animals bearing a special body cavity called coelenteron (gastrovascular cavity). They exhibit dimorphism and display two major forms namely polyp (sedentary) and medusa (swimming). They also exhibit trimorphism (e.g., Siphonophora) and polymorphism (e.g., Porpita). Body Wall They are diploblastic animals and their body wall contains several types of cells, e.g., stinging cells (cnidoblast/nematocyst), interstitial cells (totipotent cells), sensory cells, nerve cells, etc. 50 Handbook of Biology (a) (b) Lasso Shaft or butt Barbules Operculum Nematocyst Barb Coiled thread Muscular fibrils Nucleus Nematoblast Cnidocil Lasso Nucleus Muscular fibrils Nematocyst Operculum Shaft or butt Barb Barbules Everted thread Cnidocil Cnidoblast Cells : (a) Undischarged (b) Discharged
  • 61. Skeleton In coelenterates, skeleton may be endoskeleton, exoskeleton or absent. l Endoskeleton e.g., Alcyonium (fleshy mesogloea), Pennatula (axial rod of calcified horn). l Exoskeleton e.g., Millipore (coenosteum), Gorgonia (gorgorin), Madrepora (corallum). l Absent e.g., sea anemones. Metagenesis It is like the alternation of generations between the sexual (medusa) and asexual (polyp) forms. In contrast to alternation of generation in metagenesis, it is difficult to distinguish between asexual and sexual forms as both individuals are diploid. Reproduction It occurs both by sexual and asexual means. (i) Asexual reproduction By external budding. (ii) Sexual reproduction By sexual medusae. The development is usually indirect which occurs through ephyra, planula and hydrula larvae. Classification of Coelenterata Common and Scientific Names of Some Coelenterates Common Names of Coelenterates Scientific Name Common Names of Coelenterates Scientific Name Sail-by-wind Valella Organ-pipe coral Tubipora Portuguese man of war Physalia Stag horn coral Madrepora Stinging coral Millipora Mushroom coral Fungia Sea anemone Metridium Star coral Astraea Dead’s man finger coral Alcyonium Animal Kingdom 51 Phylum–Coelenterata Hydrozoa Anthozoa (Actinozoa) Scyphozoa Three classes Both polyp and medusa present. Polyp stage dominant, medusa stage reduced or absent. Velum is present. Gonads are epidermal in origin. Larva hydrula, planula, Medusa form is dominant. Polyp represented as scyphistoma stage. Pseudovelum is present. Gonads are endodermal in origin. Larva ephyra. Gonads, if present are endodermal in origin. Corals and sea anemone. • • • • • Medusa form is absent. Velum is absent. • • • • • • •
  • 62. Economic Importance l They take part in the formation of coral reefs, e.g., Millipora (stinging coral). l Their skeleton has medicinal value, e.g., Tubipora (organ-pipe coral). l They have ornamental value, e.g., Astraea (star coral). Phylum–Ctenophora The members of this phylum are generally marine, solitary, free-swimming or pelagic. They are diploblastic animals and acoelomates. Peculiar Characteristics A gelatinous mesoglea is present between epidermal and gastrodermal tissue layers. They are also called comb plates. Colloblast cells are the sensory and adhesive cells. Reproduction Sexes are not separate. All are hermaphrodites. Gonads develop from endosperm. Fertilisation is internal. Development is indirect through cydippid larva. Classification of Ctenophora Common and Scientific Names of Some Ctenophores Common Name of Ctenophores Scientific Name Venus Girdle Velamen Sea walnut Pleurobrachia Swimming eye of cat Beroe Economic Importance l They reproduce quickly and are good predators. l They can bring down an ecosystem. 52 Handbook of Biology Phylum–Ctenophora Tentaculata Nuda Two classes Possesses tentacles Contains two long aboral tentacles , , etc. e.g., Ctenoplana Velamen e.g., Beroe, etc. • • • Does not possess tentacles. Have a highly branched gastrovascular cavity. • • •
  • 63. Phylum–Platyhelminthes They are dorsoventrally flat animals having either unsegmented and leaf-like (e.g., flukes) or segmented and ribbon-like (Taenia) body. They are the first animals to have bilateral symmetry and to undergo cephalisation. Habitat They are mostly found as free-living forms, but few of them are parasitic in their habitat. Peculiar Features These are the first animals with triploblastic layers in body wall and organ system organisation. They are acoelomates due to the presence of a mesodermal connective tissue, parenchyma, in between the visceral organs. These animals have ladder-type nervous system and peculiar cells called flame cells or protonephridia for excretion. These cells are modified mesenchymal cells. Animal Kingdom 53 Nucleus Pseudopodia Globules of excretion Basal granules Cell lumen Ciliary flame Termination of capillary duct Flame cell (Solenocyte) Ectoparasites ( and ) e.g., Diplozoon Gyrodactylus Endoparasites ( and ) e.g., Echinococcus Taenia Parasitic forms Freshwater ( and ) e.g., Dugesia Planaria Free-living forms Marine ( and ) e.g., Convoluta Thysanozoon Terrestrial ( and ) e.g., Bipalium Geoplana Platyhelminthes
  • 64. Reproduction These animals are generally bisexual. Cross- fertilisation occurs in trematodes, while self-fertilisation occurs in cestodes. Fertilisation is always internal. Turbellarians reproduce by transverse fission. Life Cycle of Taenia solium 54 Handbook of Biology Fertilised ova (zygotes) in the mature proglottids capsules containing zygotes in gravid proglottids. Adult tapeworm in human gut Onchosphere (larvae) in the gravid proglottids. It contains all embryonic membranes along with a hexacanth (structure with 6 hooks). Onchospheres in human faeces (outside the body). Faeces containing onchospheres is eaten by pig. Hexacanth It is the six-hooked larval stage containing a pair of penetration glands. Each cysticercus develops into young tapeworm in the human gut. Cysticercus Hexacanth reaches heart liver and finally muscles tongue, shoulder, neck, thigh and settles to develop into next larval stage called cysticercus or bladder worm within 10 days of infection of the secondary host. It is the infective stage of human when they feed infected meat. via Bladder Neck showing strobilation Rostellar hooks Scolex Sucker (Cysticercus) Germ layer (Oncosphere) Bladder Hooks The graphical representation of life cycle of Taenia solium depicting different larval stages and adult form in the primary and secondary hosts
  • 65. Life Cycle of Fasciola hepatica Classification of Plathelminthes Common and Scientific Names of Some Platyhelminthes Common Names of Platyhelminthes Scientific Name Common Names of Platyhelminthes Scientific Name Liver fluke Fasciola hepatica Pork tapeworm Taenia solium Planarian Dugesia Hydatid worm or dog tapeworm Echinococcus granulosus Animal Kingdom 55 Phylum–Platyhelminthes Turbellaria Cestoda Trematoda Three classes Mostly non-parasitic and free-living. Unsegmented and flat leaf-like. Body wall contains syncytial epidermis with rod-shaped rhabditis, e.g., Planaria. Exclusively endoparasites Segmented and ribbon-like. Body wall is lined by microvilli. e.g., Taenia. • • • • • • Ecto or endoparasites. Unsegmented and flat leaf-like. Body wall contains cuticular spines, e.g., Fasciola. • • • Adult in the liver of sheep Fasciola Large number of eggs in faecal matter of sheep. Development of egg into next larval stage miracidium. Miracidium First larval stage freely swim in water with the help of cilia present all over body. Penetrate secondary host snail reaches to salivary gland and forms second larval stage sporocysts. Sporocyst It is the second larvae of living in pulmonary tissues of snail and obtaining nutrition from it and develops into 5-8 rediae. Fasciola Rediae It is the most important larval stage and it bears an anterior end with a ring of collar, a birth pore and pair of projections (lappets or procruscula). During Winter Every rediae produces, 14-20 cercaria (next larval stage). It replicates giving rise to the same form, daughter rediae. During Summer i.e., Cercaria It escapes from the secondary host through pulmonary sac. Its tail help in swimming of the larvae in water. After 2-3 days, it loses its tail and becomes incepted on grass or aquatic plant and is now called letacercaria. Metacercaria This is the encysted infective stage of the and now infects vertebrate host (sheep). Fasciola Graphical representation of life cycle of Fasciola hepatica depicting polyembryony along with different larval stages
  • 66. Economic Importance l Fasciola causes fascioliosis or liver rot which is characterised by hepatitis. l Echinococcus causes hydatid disease which is characterised by enlargement of liver. Phylum–Aschelminthes They are long, cylindrical, unsegmented and thread-like animals with no lateral appendages, so these are commonly called roundworms, bagworms or threadworms. Peculiar Features Body wall of these pseudocoelomate animals is composed of complex cuticle, syncytial epidermis and only longitudinal muscles. They have tube-within-tube plan of digestive system. They have fixed number of cells in every organ of the body (eutylic condition). Excretory system is H-shaped and contains rennete cells. Reproduction Sexual dimorphism is present and males are smaller than females. Fertilisation is internal and it may be direct or indirect. 56 Handbook of Biology Females Ova Males Sperms → → → → (4th moult) Back to intestine In stomach In oesophagus Swallowed into gullet In pharynx In trachea In bronchi In bronchioles Fourth stage juvenile (3rd moult) Third stage juvenile (2nd moult) Bores into lung alveoli (stays for 10 days) In lung capillaries ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ Spiral, determinate cleavage First stage juvenile or rhabditi- form larva (first moult) Second stage juvenile Embryonated egg swallowed by human host Egg hatches out in intestine Bores through intestinal wall into blood capillaries In mesenteric vein In hepatic portal vein In liver capillaries In hepatic vein ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ In pulmonary artery Right auricle In posterior vena cava ← ← Adults ↑ 3-4 days Liver Lungs 5 days (Secondary Migration) (Primary Migration) 3-4 days Heart ↓ ↑ Fertilised eggs out with host faeces ↓ Life cycle of Ascaris A graphical representation of life cycle of Ascaris
  • 67. Classification of Aschelminthes Common and Scientific Names of Some Aschelminthes Common Names of Aschelminthes Scientific Name Common Names of Aschelminthes Scientific Name Roundworm Ascaris lumbricoides Guinea worm Dracunculus medinesis Root-knot eel worm Meloidogyne marioni Pinworm Enterobius vermicularis Filarial worm Wuchereria bancrofti Whipworm Trichuris trichiura Eye worm Loa loa Economic Importance l Ascaris causes ascariasis in humans. l Meloidogyne is a harmful phytoparasitic nematode. Phylum–Annelida Annelids are segmented worms with an elongated body possessing triploblastic layers. Their musculature is formed of only smooth muscle fibres of two types, i.e., longitudinal (inner) and circular (outer) muscles. Animal Kingdom 57 Phylum–Aschelminthes Nematoda Body wall have cuticle, epidermis and longitudinal muscles. Excretory system is formed of renette cells. Nematophora Rotifera Gastrotricha Kinorhyncha Cuticle is highly thickened and formed of collagen fibres. Excretory system absent. Cuticle is formed of plates (lorica) and body wall contains both circular and longitudinal muscles. Formed of two protonephridia. Cuticle is produced into short spines. Formed of two protonephridia. Cuticle is spiny, but without cilia. • • • • • • • • Aphasmida Phasmida Phasmids, caudal sensory organs are present, , , , , , , , etc. i.e., e.g., Anguina Ancylostoma Ascaris Enterobius Dracunculus Wuchereria Loa loa Without phasmids, the caudal sensory organs. Usually free-living, and , etc. i.e., e.g., Trichinella Trichuris •
  • 68. Peculiar Features l These animals show metameric segmentation, i.e., the external division of the body by annuli corresponds to internal division of coelom by septa. l These are the first animals to have circulatory system. l Locomotory organs are minute rod-like chitinous setae or suckers which are embedded over parapodia. l A characteristic circumoesophageal ring is present in the anterior part of CNS. l Special structures called nephridia are present for excretion. Reproduction Asexual reproduction By fragmentation is seen in some polychaetes. Sexual reproduction Sexes are either united (e.g., oligochaetes) or separate (e.g., polychaetes). Fertilisation is internal (e.g., Hirudinaria) or external (e.g., earthworm). Development is direct in monoecious form and indirect in dioecious form involving a free-swimming trochophore larva. Classification of Annelida Common and Scientific Names of Some Annelids Common Names of Annelids Scientific Names Common Names of Annelids Scientific Names Earthworm Pheretima posthuma Paddle worm Chaetopterus Clam worm Nereis Blood worm Glycera Polalo worm Eunice Skate sucker Pontobdella Sea mouse Aphrodite Lung worm Arenicola 58 Handbook of Biology Phylum–Annelida Polychaeta Hirudinea Oligochaeta Three classes Marine, fossorial or tubicolous. Distinct head bearing tentacles, palps and eyes. Bristle-like setae and parapodia for locomotion Clitellum is absent. Unisexual, and e.g., Aphrodite Chaetopterus. Mostly freshwater, few marine. No cephalisation Locomotion by anterior and posterior suckers. Clitellum appears during breeding season. Bisexual, and e.g., Hirudinaria Acanthobdella. • • • • • • Terrestrial, freshwater Distinct head with eyes (palps and tentacles are absent). Locomotion by peristalsis, parapodia is absent. Permanent clitellum is present. Bisexual, and e.g., Pheretima Tubifex. • • • • • • • • •