Biodiversity refers to all the diverse plants, animals and microorganisms present on earth.
Biological diversity or biodiversity is the occurrence of diverse or varied forms of living beings which differ from one another in external appearance, size, colour pattern internal structure, nutrition, behaviour, habitat, etc.
They range in size from microscopic bacteria, hardly a few micrometers in size, to Blue Whale (about 30 m in length) and Redwood
trees (Sequoia) of California (about 100 m in height). Similarly some pine trees (e.g. Pinus) live for thousands of years while many insects
like mosquitoes have a life span of a few days. There are transparent jelly fishes and worms on one hand to brightly coloured birds and
flowers on the other hand.
It is estimated that there are at least 10 million different species of plants and animals living today, but only 1.7 million have been described so far worldwide.
CLASSIFICATION
Classification is the arrangement of organisms into groups and subgroups on the basis of their similarities and dissimilarities.
The bewildering variety of life around us has evolved on earth. In order to make relevant groups to study, variety of life forms, we classify organism.
Classification makes the study of different type of organisms easy and systematic.
From classifiction, we can know all life forms together and as a whole.
Classification reveals the inter-relationship among organisms.
It helps in understanding the other branches of life sciences.
Hierarchy :- Hierachy is a system of classification into which taxonomic categories are arranged in descending order.
Category :- Plants and animals are ranked in an arrangement of known categories. Such as Kingdom, Phylum (for animals) or
Division (for plants), Class, Order, Family, Genus and Species.
Taxon :- Taxon is defined as a unit of classification of organisms which can be recognised to a definite category at any level of
classification e.g. fishes, insects etc.
Kingdom --> Largest Group
Phylum (for animals) / Division (for plants)
Class
Order
Family
Genus
Species --> Lowest group
Charles Darwin first described the idea of evolution in 1859 in his book, "The Origin of Species".
Darwin suggested that organisms are related to each other by descent. They had common ancestors from which they gradually evolved into their present form.
The ancestral forms were simple and are called 'primitive' and primitive organisms have evolved into advanced orgamisms which are more complex.
This process of gradual change from simple life forms to complex life forms is called 'Evolution'.
NOMENCLATURE : (The naming of organisms)
Binomial Nomenclature : Binomial nomenclature was proposed by Carolus Linnaeus. According to him the name of any organism consists of two words.
The first word denoting the name of 'genus' and second word denoting 'species'.
First letter of generic name must be written in capital lettter whereas species name is started with small letter.
Scientific name is generally derived from Greek or Latin words.
The binomial names are printed in italics and underlined separately when written.
Examples :
Potato - Solanum tuberosum Tiger - Panthera tigris
BIOLOGICAL CLASSIFICATION :
Artificial system : It based on habit, habitat and a few morphological characters.
e.g. Aristotle classified living organisms on the basis of habitat into water, land and air.
Theopharastus grouped plants on the basis of their habits into trees,shrubs, undershrubs and herbs.
Natural Systems : It based on natural affinities.
e.g. Bentham and Hooker's classification of seed plants.
Phylogenetic Systems :
Based on evolutionary relationships of organisms.
e.g. Engler and Prantl's classification of flowering plants.
KINGDOM SYSTEM
1. Two Kingdom Classification :
First suggested by Carolus Linnaeus in 1758.
Living organisms have been divided into two kingdoms.
(i) Kingdom Plantae - All the plants constitute kingdom planate. The kingdom includes bacteria, lichens, fungi, algae, bryophytes,
ferns, gymnosperms and angiosperms.
(ii) Kingdom Animalia - All the animals constitute kingdom animalia. The kingdom animalia includes protozoans, sponges, Hydra, Jelly
Fish, worms, insects, spiders, octopus, star fish, fishes, frogs, salamanders, lizards, snakes, birds and mammals.
Drawbacks in two kingdom classification :-
Certain organisms did not strictly fit either under plant or animal kingdom like : Euglena and Viruses.
Five kingdom classification :
This concept was propounded by Robert H. Whittaker in 1969.
On the basis of cell structure, complexity in organisms and type of nutrition, he divided living organisms into 5
kingdoms.(i) Monera, (ii) Protista, (iii) Fungi, (iv) Plantae, (v) Animalia.
Carl Woese (1977, 1994) has divided the kingdom monera into archaebacteria (= archea) and eubacteria
(or bacteria). All other kingdom are included in his superkingdom of eukarya.
Practice Zone - 1.1
1. Who is the father of modern taxonomy ?
2. What is the basic unit of classification ?
3. Who wrote "The origin of species" ?
4. Name the book which was written by Carolus Linnaeus.
5. Give the scientific name of tiger.
6. Who was the founder of trinomial nomenclature ?
7. Who gave five kingdom classification ?
8. What is the basis of artificial classification system ?
CHARACTERISTICS OF FIVE KINGDOMS
1. Kingdom - Monera :
Prokaryotic Nature : The genetic material is not
organised into a nucleus. It lies directly inside the
cytoplasm and is called nucleoid.
Membrane Bound Cell Organelles. Membrane bound
cell organelles like mitochondria, Golgi apparatus ,
plastids, lysosomes, are absent.
Unicellular Nature : Monerans are basically unicellular.
In filaments and colonies the cells are similar and independent.
Mode of nutrition is either autotrophic (Blue-green algae) or heterotrophic (Mycoplasma and most bacteria).
Some organisms have cell wall (in bacteria) while other lacking (in Mycoplasma).
Examples :
Blue Green Algae (Cyanobacteria) – Anabaena, Nostoc.
Bacteria – (Vibrio cholerae, Clostridium botulinum, Escherichia coli)
Mycoplasma – (Produces diseases in humans, animals and plants).
2. Kingdom - Protista :
Organisms are unicellular, eukaryotic organization.
There is a true nucleus and membrane bound other cell organelles.
Cell wall : Some protists are covered with cell wall (most photosynthetic protists) while others do not possess it (e.g., protozoan protists).
Mode of nutrition is either autotrophic (algae and diatoms) or heterotrophic (protozoans).
Some organisms have cilia (e.g. Paramecium) ; flagellum (e.g. Euglena) and pseudopodia (e.g. Amoeba) for locomotion.
Sexual reporduction is present but an embryo stage is absent.
Examples : Unicellular algae – Chlamydomonas, Chlorella
Diatoms – Pinnularia, Navicula
Dinoflagellates – Gonyaulax, Noctiluca
Protozoa – Amoeba, Plasmodium, Euglena, Paramecium
3. Kingdom - Fungi
These are non-green (lacking chlorophyll) eukaryotic, organisms.
They may be unicelluar (e.g. Yeast) or Multicellular (most fungi).
The body of a multicellular and filamentous fungus is called mycelium and is composed of several thread like structures termed as hyphae.
Heterotrophic mode of nutrition is found.
Food is gained by either saprophytically (from dead organic matter) or parasitically (from other living tissues).
Cell Wall contain - Chitin.
Reserve food material - Glycogen.
Examples : Yeast, Rhizopus (Bread mould), Penicillium, Mucor, Mushroom (Agaricus) ; Smut (Ustilago).
DO YOU KNOW ?
LICHEN- Symbiotic association between algae and fungi.
Algal component is known as "Phycobiont" and fungal
component is called "Mycobiont".
The alga manufactures food not only for itself but also for the
fungus. Fungus provides protection to alga, helps in fixation and
absorption of water as well as minerals.
They are a source of essences, dhup, havan samagri and some
medicines.
Examples : Crustose lichen - Rhizocarpon
Foliose lichen - Parmelia
Fruticose lichen - Usnea
4. Kingdom - Plantae
Plants are multicellular, eukaryotes with cellulosic cell wall.
They are autotrophs i.e. prepare own food by photosynthesis.
5. Kingdom - Animalia
Animals are multicellular, eukaryotes without Cell Walls.
They are heterotrophic.
Practice Zone - 1.2
1. Who proposed 5-kingdom classification ? 2. What is monera ?
3. Give two examples of monera. 4. What is protista ?
5. What is mixotrophic nutrition ? 6. Give one example of protozoan protistan.
7. Give one example of algal protists. 8. Which one is called plant animal ?
9. What are fungi ? 10. What is mycelium ?
11. What is chemical characteristic of fungal cell wall ? 12. Give two examples of fungi.
13. What is lichen ? 14. Give one use of lichen.
KINGDOM-PLANTAE
Characteristics : Plantae includes multicellular, eukaryote organisms with cellulosic cell wall.
A mature plant cell commonly possess a single large central vacuole.
Plastids are found in all plants. Some plastids posses photosynthesic pigment. They are called chloroplasts.
Plants are autotrophic in nature because they are able to perform photosynthesis with the help of chlorophyll present in
chloroplasts. Reserve food is starch.
Eichler (1883) divided the kingdom plantae into two subkingdoms, cryptogamae and phanerogamae.
Subkingdom : Cryptogamae (Gk. cryptos – hidden, gamous – marriage). The reproductive organs are inconspicuous. Flowers and
seeds are absent. The embryo, if present is naked. Plants of subkingdom cryptogamae are also called lower plants, flowerless and
seedless plants. There are three divisions in this subkingdom – Thallophyta, Bryophyta, Pteridophyta.
Subkingdom Phanerogamae (Gk. phaneros – visible, gamous – marriage). The plant which possess visible and well differentiated
reproductive organs are called phanerogams. The plants of subkingdom phanerogamae have well differentiated and evident reproductive organs
like flowers or cones, they are also called as seed plants as they beared seeds. Phanerogamae has single division of spermatophyta.
Basis of Classification
On the basis of differentiation of plant body.
On the basis of conducting tissue.
On the basis of ability to bear seeds and if seeds are enclosed within the fruits.
Following plant groups are included in kingdom-Plantae
1.Thallophyta
Main plant body is gametophyte (haploid).
Plant body is not differentiated into root, stem and leaves, ans is called as thallus.
These are found in marine, fresh water and moist land.
They do not have mechanical and conducting tissue.
Asexual reproduction generally take place by spores.
Sex organs are simple, single-celled, (the male sex organs
are called as antheridia and female sex organ are called
oogonia) and their is no embryo formation after fertilization.
Examples :
Green algae - Spirogyra, Ulothrix, Cladophora,
Chara, Ulva, Chlorella
Brown algae - Laminaria, Fucus, Sargassum.
Red Algae - Polysiphonia
*Gametophyte is haploid (with one set of chromosomes) plant body which produces gametes directly.
*Sporophyte is diploid (with two sets of chromosomes) plant body which produces haploid spores through the process of meiosis.
Sporophyte is formed from diploid zygote, after the fusion of spores.
2. Bryophyta
Bryophytes are also known as amphibians of plant kingdom.
These are the simplest and the most primitive land plant.
They have flat plant body which differentiate into stem and leaf like structure.
Main plant body is gametophyte which attach to substratum by means of rhizoids.
Sex organs are multicellular and jacketed. Male sex organs are called antheridia while female sex organs are called archegonia.
Examples :
Liver wort - Riccia and Marchantia
Horn wort - Anthoceros
Moss - Funaria
3. Pteridophyta -
Main plant body is sporophyte which is differentiated into root, stem and leaves.
Vascular tissues, xylem and phloem, appear for the first time in pteridophyta.
They produces spores inside sporangia.
Gametophyte is a small but independent stage
in life cycle.
Sex Organs are multicellular and jacketed like those of bryophytes – male antheridia, female archegonia.
Male gametes need water for fertilization.
Seeds are absent.
Examples :
Club moss - Selaginella, Lycopodium
Horse tails - Equisetum
Ferns - Marsilea, Azolla, Adiantum,
Dryopteris, Pteris and Pteridium.
The thallophytes, bryophytes and pteridophytes have naked embryos that are called spores.
All of these have inconicuous reproductive organs are called cryptogams or those with hidden sex organ.
Embryophytes – Plants having an embryo stage in their life cycle – bryophytes, pteridophytes, seed plants.
Sporophyte lives as a parasite over it.
Tracheophyta – Plant group having vascular tissues – pteridophyta and spermatophyta.
Practice Zone - 1.3
1. Define thallus.
2. Mention two important characteristics of thallophyta.
3. What is the chemical characteristics of algal cell wall ?
4. To which division of cryptogams do algae belong ?
5. Name the division which is known as "amphibians of plant kingdom".
6. Name the plant structure, which helps in attaching the bryophytes to the substratum.
7. What is peculiar about sex organs in bryophytes ?
8. Give two examples of bryophytes.
9. Give two examples of pteridophytes.
10. Name the group of vascular cryptogams.
Spermatophyta (Gk. sperma – seed, phyton – plant)
Characteristics Main plant body is a sporophyte which is differentiated into stem, leaves and roots.
Vascular tissues are well-developed throughout the plant body.
Sporangia occur over modified leaves called sporophylls. Sporophylls are aggregated to form cones or flowers.
Male and female gametophytes are distinct. They are small and dependent on the sporophyte for their nutrition.
Male gametophytes or pollen grains reach near the female sex organs through an external agency of wind, water or animals. This process
is called pollination. Fertilization occurs with the help of a pollen tube. An external water is not required.
After fertilization plants produce seeds which contains embryo along with stored food. On germination each seed forms a new plant.
Spermatophyta or phanerogams are classified into two groups (Gymnosperm, Angiosperm) on the basis of naked or enclosed seeds.
4. Gymnosperm : Gymno- naked and sperm - seeds.
Plants are evergreen, woody and perennial. They are trees and shrubs.
Sporophylls are aggregated to form cones.
There are separate male and female cones.
They bear naked seed. The seeds are not enclosed inside fruits. Instead they lie exposed over the megasporophylls.
Xylem lack vessels and phloem lack companion cells in Gymnosperm.
Examples : Cycadae - Cycas
Coniferae - Pinus (Pines), Cedrus (deodar), Ginkgo.
5. Angiosperm - Angio- covered and sperm - seed.
Characteristics : These Plants are deciduous or evergreen, annual biennial or perennial herbs, shrubs or trees.
These are called flowering plant. Sporophylls are aggregated to form flowers. Flowers may be unisexual or bisexual.
Pollination occurs by wind, water and animals.
The plants of this group produce seeds inside an organ called ovary, which is modified in to fruit.
Endosperm is a new food storing structure which is generally triploid and is formed by fusion of three nuclei (triple fusion).
Embryo is present in the seed and bear leafy or fleshy structures called cotyledons (seed leaves)
Cotyledons represent a bit of pre-designed plant in the seed.
In angiosperms, a seed may have one or two cotyledons. On the basis of cotyledon number, angiosperms have been divided into two
classes, dicotyledoneae and monocotyledoneae.
CLASS DICOTYLEDONEAE
It is a class of angiosperms in which seeds possess tow cotyledons. The plants of this class are commonly called dicots or
dicotyledonous plants. Some other characters are reticulate venation, tap root system, pentamerous or tetramerous flowers. eg. Gram, Pea, Mustard, Ipomoea.
CLASS MONOCOTYLEDONEAE
The members of class monocotyledoneae of angiosperms are characterised by the occurrence of a single cotyledon in their seeds. They are commonly called monocots or monocotyledonous plants. Other characters of monocots are parallel venation, fibrous root system, trimerous flowers. eg. Lily, Coconut, Wheat, Maize, Grass, Bamboo, Paphiopedilum.
KINGDOM ANIMALIA
Characteristics :
(i) Cellular Nature : Members of kingdom animalia are wall less, eukaryotic and multicellular.
(ii) Nutrition : It is heterotrophic.
(iii) Locomotion : Most animals are mobile.
"Terminology" used in classification -
Grades of Body Organization -
(i) Cellular grade - e.g. Sponges
(ii) Cell-tissue grade - e.g. Coelenterates
(iii) Tissue - Organ grade - e.g. Flatworms
(iv) Organ- System grade - e.g. Aschelminthes to Chordates.
Body Plans -
(i) Cell aggregate - e.g. Sponges
(ii) Blind sac - e.g. Coelenterates , Flatworms
(iii) Tube within a tube - e.g. Aschelminthes to Chordates
Body symmetry - It is similarity in arrangement of body parts.
(i) Radial symmetry- Body can be divided into similar halves by any plane passing through centre axis.
(ii) Bilateral symmetry- Body can be divided along a median longitudinal plane into two mirrored portions right and left halves.
Germ layers -
(i) Diploblastic animals - having two germ layers i.e. ectoderm and endoderm.
(ii) Triploblastic animals - having three germ layers i.e. ectoderm, endoderm and mesoderm.
Metameric segmentation - Body is divided into segments externally as well as internally (by septa).
Body Cavity [Coelom] -
A body cavity is a fluid-filled space between the gut and the outer body wall of an animal.
(i) Acoelomates : Animals without coelom e.g. Flatworms
(ii) Pseudocoelomates : In these animals, coelom is not lined by mesoderm. e.g. Nematodes.
(iii) True coelomates : In these animals, coelom is lined by mesoderm.
True coelom may be of two types :
(i) Schizocoelom : Coelom is originated by spliting of mesoderm. e.g. Annelids, Arthropods, Molluscs.
(ii) Enterocoelom : Coelom is originated by endodermal pouches. e.g. Echinodermates, Hemichoradates, Chordates.
Body temperature :-
(i) Ectotherm or Poikilotherm or Cold-blooded :
Their body temperature changes according to enviornmental temperature. e.g. Pisces, Amphibians, Reptiles.
(ii) Endotherm or Homeotherm or Warm- blooded :
Their body temperature cannot change according to environmental temperature. e.g. Mammals, Aves.
1. PHYLUM PORIFERA-PORE BEARING ANIMALS
[Gk. porus - pore ; ferre - to bear]
Common name - "the sponges"
General Characters :
1. They live mostly in the sea (marine) but a few occur in fresh water.
2. They have cellular level organization with two germ layer i.e. diploblastic animals.
3. They are sessile or stationary.
4. Most of sponges are asymmetrical, some are radially symmetrical.
5. Sponges have pores on body and these pores are called ostia. Ostia open into a canal system and the canal opens to outside by
a large opening ; named osculum present at top.
6. Skeleton of sponges is made up of minute calcareous or siliceous spicules or spongin fibres.
e.g. Sycon (Scypha) - Urn sponge
Euplectella - Venus's flower basket Hyalonema - rope sponge
Cliona - boring sponge Euspongia - bath sponge
Spongilla Olynthus
2. PHYLUM CNIDARIA OR COELENTERATA
[Gk. Knide = sting cells]
General Characters :
1. Aquatic animals mostly marine, some live in colonies (corals) while other live solitary.
2. Body is radially symmetrical.
3. These are the first multicellular animals having tissue level organization with distinct labour of division.
4. Body has a central gastrovascular cavity- coelentron which lacks anus but has mouth which is surrounded by tentacles.
5. The body bears specialized cells-cnidoblasts, bearing stinging cell organelles called 'nematocysts'.
6. Nematocysts serve the function of paralysing the prey by injecting poison.
8. Nervous system is primitive, has only network of nerve cells (nerve net).
9. Coelenterates show two main forms, the polyp (asexual) and the medusae. (sexual)
e.g. Hydra : fresh water coelenterate
Obelia Millepora-coral
Physalia -Portugese man of war Aurelia -jelly-fish
Pennatula - sea-pen Metridium- sea-anemone
Corallium- red coral Gorgonia- sea fan
3. PHYLUM PLATYHELMINTHES
[Gk. platys = Flat ; helmin = worm]
Common name : Flatworms
General Characters :
1. Mostly parasitic animals, some are free-living (e.g. Planaria) and aquatic.
2. They are triploblastic animals showing bilateral symmetry and tissue organ grade of body organization.
3. The organisms are unsegmented, dorsoventrally flattened.
4. Body cavity (coelom) is absent i.e. acoelomate.
5. Suckers and hooks are usually present.
6. Alimentary canal has only one opening i.e. mouth, anus is absent.
8 Excretory system consists of blind tubules called protonephridia; having flame cells.
9. They are hermaphrodite i.e. male and female reproductive organs are present in same animal.
e.g. Planaria or Dugesia Microstomum- Energy of Hydra.
Fasciola- Liver fluke Schistosoma - Blood fluke
Taenia solium - Pork tape worm.
4. PHYLUM NEMATODA OR ASCHELMINTHES
[Gk. nema = thread ; helmin = worm]
Common name - Thread worm or Round worm
1. They are parasitic, most are free living (in fresh or marine water or terrestrial).
2. They have narrow, elongated and cylindrical bodies. Body is covered by cuticle.
3. Triploblastic unsegmented animals with bilateral symmetry and organ system level of organization, having tube within tube body plan.
4. Pseudocoelom is present.
5. Alimentary canal straight and complete with mouth and anus.
6. Unisexual organisms.
e.g. Ascaris - round worm ; Enterobius - pin worm ; Wuchereria - filarial worm ; Ancylostoma - Hook worm.
5. PHYLUM- ANNELIDA
[Gk. annulus = ring ; lidos = form]
Common Name : Segmented worms
General Characters :
1. They occur in fresh water, sea water or moist soil. Some are free living, some are burrowing and a few are parasites.
2. Body is metamerically segmented i.e. body is divided externally by transverse grooves as well as internally by septa, these segments are called metameres.
3. They are the first animals with true body cavity i.e. coelom.
4. They are bilaterally symmetrical, triploblastic animals.
5. Body is covered by thin cuticle.
6. Locomotion by parapodia or Chitinous setae which are segmentally arranged.
7. Alimentary canal is complete.
8. Respiration is through the general body surface.
9. Excretion by nephridia.
10. Blood vascular system is closed. Blood is red due to the presence of the pigment " haemoglobin.
11. The nervous system consists of a dorsal "brain" and a ventral nerve cord having ganglia and lateral nerves in each body segment.
12. Sexes may be united (hermaphrodite) or separate.
e.g. Nereis - sand worm (clam worm) Aphrodite - sea mouse
Pheretima - Earthworm Megascolex - Largest earthworm
Hirudinaria - Indian cattle leech Bonellia
Hirudo - medicinal leech.
6. PHYLUM ARTHROPODA
[Gk. Arthron = joint ; Podas = foot]
Common Name : The animals with jointed feet.
The largest group of animals
General Characters :
1. They are found everywhere on earth- on land, in soil, in water and as parasites on plants and other animals.
2. Triploblastic, bilaterally symmetrical and metamerically segmented animals.
3. The body is segmented into 2 regions- head and thorax together and abdomen or 3 regions- head, thorax and abdomen. Anterior part of
body forms a distinct head, bearing sense organs . Animals have jointed legs (3 or more pairs).
3. Arthropods have compound eyes, having many lenses to make mosaic vision.
4. Exoskeleton is made of chitin.
5. The body cavity is filled with blood i.e. haemocoel. Open circulatory system is present.
Blood may be colourless - Haemolymph (e.g. insects) or with copper contain pigment - Haemocycanin (e.g. prawn)
6. Mouth parts adapated for biting, chewing, piercing and sucking.
7. Respiration occurs through general body surface, gills trachae or book lungs.
8. Excretion occurs by 'Malpighian tubules' or green glands or coxal glands.
9. Sexes are separate.
e.g. Peripatus Palaemon - (Prawn)
Cyclops - one eyed giant Cancer - crab.
Scolopendra- Centipede Julus - Millepede
Lepisma - Silver fish Melanopus - grasshopper
Schistocerca - Locust Gryllus - house cricket
Periplaneta - Cockroach Musca - House fly
Apis - honey bee Anopheles - mosquito
Culex - mosquito Cimex - bed bug
Pieries - Butterfly Bombyx - silkmoth
Limulus - king crab Palamnaeus- scorpion
Arnea - spider Argus- ticks
7. PHYLUM- MOLLUSCA
[L. Molluscs = soft]
Common Name : The Soft Bodied Animals
The second largest group of animals.
General Characters :
1. They are mostly aquatic, living in sea water, some of fresh water.
2. They are soft, unsegmented, triploblastic, coelomate animals with bilateral symmetry.
3. The body is divided into an anterior head, a ventral muscular foot and a dorsal visceral mass of hump. Over the hump, a fold of thin
skin called mantle or pallium is present, which secretes the shell.
4 The soft body is usually supported by a hard shell of calcium carbonate.
5. Locomotion is brought about by muscular foot.
6. Buccal cavity contain a rasping organ the 'radula' for feeding.
7. Respiration occurs through gills called ctendia.
8. Open blood vasuclar system. Blood is usually blue due to a blue pigment called "haemocyanin".
9. Excretion by a pair of kidneys or metanephridia, known as Kaber's organ or Organ of Bojanus.
e.g. Neopilina - Living fossils Chiton- Coat of mail shell Pila - apple snail
Aplysia - sea hare Helix - garden snail Dentalium - tusk shell
Unio - fresh water mussel Pinctada - Indian pearl oyster Sepia - cuttle fish Octopus- devil fish Loliga - sea squid Nautilus
8. PHYLUM - ECHINODERMATA
[Gk. echinos = spines ; derma = skin/covering]
Common Name : The Spiny Skinned Animals.
General Characters :
1. They are exclusively marine animals.
2. Body is triploblastic, coelomate and without segmentation with radial symmetry in adult and bilateral in larvae.
3. Body lacks head, but has oral and aboral surfaces. Oral surface of body has five radial areas called ambulacra.
4. Body cavity is modified into water vascular system. Tube like extensions called tube feet. Tube feet help in locomotion and food collection.
5. Digestive system is complete , mouth is on the lower surface and the anus is on the upper surface.
6. Respiration by gills, genital bursae, or respiratory trees.
7. Reproduction sexual, asexual or by regeneration. Sexes are separate.
e.g. Pentaceros - sea pentagon Asterias - star fish or sea star
Ophioderma - brittle star Ophiura
Echinus - sea urchin Holothuria - sea cucumber
Antedon - sea lily or sea feathers
CHORDATA
(Gk. chorde-string)
Chordata is a phylum of triploblastic bilaterally symmetrical coelomate animals.
Diagnostic Characteristics :
(i) Notochord (Gk. noton-back, chorde-cord) : It is a long rod-like structure that develops between dorsal nervous system and gut.
Notochord functions as a support structure that provides points for attachment to muscles.
(ii) Dorsal Hollow Nerve Cord : It occurs above the notochord.
(iii) Pharyngeal Gill Slits (Gill Pouches) : They are paired respiratory structures which remain functional throughout life in
fishes and some amphibians. In others they occur only in embryo.
(iv) Post anal Tail. It occurs in most chordates for balancing, protection of genital and anal regions.
Protochordata [Lower chordates]
General Characters :
1. Exclusively all are marine.
2. These are bilaterally symmetrical, triploblastic and coelomic animals.
3. They have a rod-like structure i.e. notochord at some stages during their lives.
4. Pharyngeal gill clefts are found throughout the life span.
5. They have a dorsal tubular nerve cord.
6. Protochordes may be grouped into following subphyla-
(i) Hemichordata (ii) Urochordata (iii) Cephalochordata
Subphylum- Hemichordata
General Characters :
1. These animals possess a combination of nonchordate and chordate characters.
2. They are soft, unsegmented, worm like and bilateral symmetrical animals..
3. They have notochord as buccal diverticulum or stomochord in proboscis.
4. Body is divided into proboscis, collar and trunk.
e.g. Balanoglossus - Acorn worm.
Subphylum- Urochrodata
General Characters :
1. Notochord is present only in the tail of free living tadepole like larva
2. Adult members have test all over their body, made up of tunicin
(just like cellulose).
e.g. Herdmania – Sea potato or sea squirts.
Subphyum – Cephalochordata
General Characters
1. First complete chordate animals.
2. Notochord, Nerve cord and pharyngeal gill clefts remain throughout
the life span.
e.g. Branchiostoma or Amphioxus (Lancelet – Typical chordate)
VERTEBRATA
General Characters :
1. Vertebrates are bilaterally symmetrical, triploblastic, coelomic and segmented animals.
2. In vertebrates notochord is replaced by vertebral column.
3. Nerve cord remains enclosed within vertebral column.
Vertebrata are grouped into five classes
(i) Pisces (ii) Amphibia (iii) Reptilia (iv) Aves (v) Mammalia
(1) CLASS - PISCES
1. This class includes true fishes.
2. They are exclusively water living animals.
3. Their body is streamlined and covered by scales.
4. They have paired fins for locomotion.
5. They respire through gills.
6. Heart is two chambered.
7. Their endoskeleton is made up of cartilage or bones.
8. They are unisexual and lay eggs.
9. They are cold blooded.
Fishes are of two types based on the nature of their endoskeleton.
(2) CLASS - AMPHIBIA
[Gk. Amphi = two ; bios = life]
General Characters :
1. These are the first vertebrate which come out of water but these are not able to live on land permanently. These depend on water for their reproduction.
2. Their skin is smooth or rough, moist, slimy, glandular and without scales. To moist the skin numberous glands are found and skin
having pigment cells (chromatophores) for colouration.
3. Notochord does not persist in adults.
4. Head and trunk distinct, tail may be present.
5. Two pairs of pentadactyl (five digits) limbs are present. Digits without claws.
6. Three chambered heart has two auricles and one ventricle.
7. Respiration by gills, lungs, skin and buccal lining.
8. Excrete either ammonia (by tadepole) or urea (by adults)
9. They are cold-blooded animals.
10. Animals are unisexual; fertilization external, mostly lay eggs.
e. g. Ichthyophis – Blindworm
Salamander (Salamandra) Necturus – Mud puppy
Siren – Mudeel Bufo – Common toad
Hyla – Tree-frog Rana tigrina – Indian bull frog
Alytes – Midwife toad
(3) CLASS - REPTILIA
[L. reptare = to creep]
General Characters :
1. First successful terrestrial animals but some are aquatic.
2. Body is divided into head, neck, trunk and tail.
3. Skin is dry, cornified, rough and nonglandular. Water proof protein, keratin.
4. Two pairs of pentadactyl limbs with incurved nails or claws
5. Exoskeleton is made up of horny epidermal scales or dermal scute or bony plates.
6. Heart is three chambered i. e. two auricles and an incompletely divided ventricle. Only crocodiles have four chambered heart.
7. One pair of metanephric kidneys, animals are uricotelic
8. Fertilization is internal.
9. These are mostly oviparous, eggs are cleidoic i.e. eggs are covered by a shell made up of calcium carbonate.
10. These are cold blooded animals.
Testudo – Land tortoise Trionyx – Fresh water terrapins
Chelone – marine turtles Hemidactylus – Common lizard, wall lizard
Calotes – Garden lizard (Girgit) Varanus – Goh, monitor lizard.
Python – Azgar, largest snake Ptyas – Zamenis or Rat snake or Dhaman
Eryx – Sand boa – Dumuhi snake Typhlops – Blind snake
Naja – Indian Cobra Naja bungarus – King cobra
Crotalus – Rattle snake Bangarus – Krait snake
Vipera – Viper snake Crocodilus – Crocodile (Muggar)
Gavialius – Gharial
(4) CLASS- AVES
[L. avis = bird]
General Characters :
1. All types of birds are included in this class.
2. Body is boat shaped and covered by soft feathers, called "plumage".
3. Fore limbs modified into wings for flight.
4. Hind-limbs bear four clawed digits and are adapted for walking and perching.
5. Teeth are absent, jaws form a horny beak.
6. Endoskeleton is made up of hollow, air-filled bones, known as pneumatic bone.
7. Four chambered heart with two auricles and two ventricles is present.
8. They excrete uric acid.
9. Sound producing organ at the junction of trachea and bronchi of birds is called syrinx.
10. Parental care is present.
11. Fertilization internal. They are oviparous and lay large, eggs having hard shell.
12. They are warm-blooded animals.
Penguins, Emu, Ostrich and Kiwi are flightless birds.
Archaeopteryx – Connecting link between reptiles and birds.
Gallus – Chicken Passer – House sparrow Corvus – Crow Columba – Pigeon Psittacula – Parrot Pavo – Peacock
(5) CLASS - MAMMALIA
[L. mamma = Breast]
General Characters :
1. Members are cosmopolitan.
2. Body is divided into head, neck, trunk and tail with movable eyelids
3. Mammary glands are found in females for baby feeding.
4. The body is covered by a coat of hairs (made of keratin). Cutaneous glands such as sweat glands and oil glands.
5. They have two pairs of pentadactyl limbs.
6. Fleshy external ear (pinnae) present.
7. Respiration is by one pair of lungs.
8. A horizontal diaphragm present in between thorax and abdomen.
9. Heart is four chambered. Non-nucleated red blood corpuscles are present in blood.
10. They excrete urea i.e. ureotelic.
11. Mammals are warm-blooded animals.
12. Sexes are separate, internal fertilization present, mostly viviparous but a few are oviparous and lay eggs (e.g. Platypus & Echidna), and
some like Kangaroos give birth to very poorly developed young ones.
Q.1 Why do we classify organisms?
Ans. There are a large number of living organisms in this biosphere having great diversity in shape, size and forms. Practically, it is
not possible to examine and study every organism separately at individual level. So, animals should be classified to make their study easy.
Q.2 Give three examples of the range ofvariations that you see in life forms aroundyou?
Ans. (a) The living organism vary in size from microbes of few micro metres to more than 100 metres tall trees.
(b) The living organisms range from colourless and transparent to brightly coloured birds and flowers.
(c) The lifespanof organisms vary from few days (few insects) to several thousand years (trees).
Q.3 Which do you think is a more basic characteristic for classifying organisms?
(a) The place where they live
(b) the kind of cells they are made of, why?
Ans. A more basic characteristic for classifying organisms is the kind of cells they are made of. The organisms are classified according to cell
type (prokaryotic or eukaryotic) and cell wall characteristic.
Q.4 What is the primary characteristic on which the first division of organism is made?
Ans. The primary characteristics used for making the broader division of organisms is 'cell type', i.e., whether the organisms are prokaryotic or eukaryotic.
Q.5 On what basis are plants and animals put into different categories?
Ans. Plants and animals differ from each other on the basis of their mode of nutrition as well as their body design. Plants are autotrophic and
perform photosynthesis whereas animals are heterotrophic and get food from other organisms. Plant cell have cell wall whereas animal
cell lacks cell wall. Animals stop growing after reaching certain size but plants continue growing till death.
Q.6 Which organisms are called primitive and how are they different from so-called advanced organisms?
Ans. The organisms that existed on the primitive earth are, referred as 'primitive' and the organisms that came into existence later as
a result of evolution are called as'advanced organisms'. Advanced organisms have well-developed features and are more complex in comparison to the primitive.
For example,unicellular prokaryotic bacteria are primitive and multicellular eukaryotic higher plants and animals are advanced.
Q.7 Will advanced organisms be the same as complex organisms? Why?
Ans. Yes, comparatively complex organisms are more advanced than the simple organisms. It is because the complexity of organisms has increased over
the evolutionary period.
Q.8 What is the criterion for classification of organisms belonging to kingdom monera or protista?
Ans. The organism which are unicellular and eukaryotic are grouped under the kingdom protista. The organisms which do not possess well-defined nucleus, cell organelles and have unicellular or multicellular body designs are grouped under the kingdom monera.
Q.9 In which kingdom will you place an organism which is single-celled, eukaryotic and photosynthetic?
Ans. Kingdom protista
Q.10 In the hierarchy of classification, which grouping will have the smallest number of organisms with a maximum of characteristics
in common and which will have the largest number of organisms?
Ans. Species possess smallest number of organisms with a maximum number of common characteristics. Kingdoms possess largest number of organisms.
Q.11 Which division among plants has the simplest organisms?
Ans. Thallophyta mongthe plants has the simplest organisms.
Q.12 How are pteridophytes different from phanerogams?
Ans. Pteridophytes do not produce seeds whereas plantsbelonging to phanerogams produce seeds.
Q.13 How do angiosperms and gymnosperms differ from each other?
Ans. Angiosperms bear seeds inside the fruit whereas gymnosperms bear naked seeds (i.e., seeds are not enclosed within the fruits).
Q.14 How do poriferan animals differ from coelenterate animals?
Ans. Poriferans possess cellular level of organisation whereas organisation.
Q.15 What are the advantages of classifying organisms?
Ans. The following are the advantages of classifying organisms.
(i) Classification of organisms make their study easy.
(ii) It is not possible for us to know about all organisms individually, thus the study of few representatives from each grou gives a
broad idea of life as a whole.
(iii) Classification helps to give information about the organism which occurs at specific places.
(iv) It reveals evolutionary trends by showing gradually increasing complexity of structure in various groups of organisms.
Q.16 How would you choose between two charateristics to be used for developing a hierarchy in classification/
Ans. Before developing hierarchy in classification, we should be aware about characteritics which should be used as the basis for
making the divisions. Then we should pick up next set of charcteristics for making sub-groups. This process must be continued and each
time new characteristic should be used. The characteristics in the next level should be independent to the previous one that will decide subsequent
division of groups.
Q.17 Explain the basis for grouping organisms into five kingdoms.
Ans. The organisms were grouped into five kingdoms on the basis of the following characteristics-
(i) Phylogenetic relationship between the organisms
(ii) Cell structure (unicellular or multicellular)
(iii) Complexity ofbody structure
(iv) Mode ofnutrition
Q.18 What are the major divisions in plantae? What is the basis for these divisions?
Ans. The major division of kingdom plantae are : (i) thallophyta (ii) bryophyta (iii) pteridophyta
(iv) gymnosperms and (v) angiosperms.
The first level of classification of plants is based on the presence and absence of well-defined distinct body components. Algae are separated
from the rest in having simple and less differentiated thalloid plant body. The next level is based on the absence and presence of vascular
tissue (i.e., xylem and phloem).
These characters separate bryophuta from rest. Further classification is based on the ability to bear seeds. Pteridophyta do not bear seeds.
The gymnosperms have naked seeds whereas angiosperms bear seeds enclosed within the fruits.
Q.19 How are the criteria for deciding division in plants different from criteria for deciding the subgroups among animals?
Ans. The criteria for deciding divisions in plants differs from the criteria for deciding subgroups among animals because of the differences in their basic structure. Plants are divided on the basis of presence of absence of seeds, flowers, differentiation of body and presence or absence of vascular tissues. Animals are divided into subdivisions on the basis of presence or absence of notochord, coelom, gill slits, body segmentation, havitat, etc.
Q.20 Explain how animals in vertebrata are classified into further subgroups.
Ans. The major characters used to classify animals in vertebrata are - (i) kind of exoskeleton or endoskeleton (ii) respiratory organs
(iii) the method of reproduction and giving birth to young ones. On the basis of these characteristics the vertebrata is divided into the following classes-
(i) Piseces - exoskeleton of scales, endoskeleton of cartilage or bones, breathing through gills
(ii) Amphibia - slimy skin, breathing through gills in larval stage
(iii) Reptilia - exoskeleton of scales, lay eggs outside the water
(iv) Aves - exoskeleton of feathers, ability to fly, lay eggs
(v) Mammalia - exoskeleton of hair, external ears, give birth to young ones.
Very short answer-type Question :
Q.1 In which kingdom will you place an organism which is single-celled, eukaryotic and photosynthetic ?
Q.2 Which division among plants has the simplest organisms ?
Q.3 Name the group in which :
(i) Seeds are naked. (ii) Reproductive organs are flowers.
Q.4 Name the basic unit of classification.
Q.5 Name two sub-kingdoms of Kingdom Plantae.
Q.6 Name the smallest taxon.
Q.7 Give two examples of monocot.
Q.8 Give two examples of dicot.
Q.9 Name a group where naked seeds are present.
Q.10 To which division of Cryptogams do algae belong ?
Q.11 Name two animals belonging to reptilian class.
Q.12 The animals belonging to a phylum have segmented body. Name the phylum.
Q.13 Which is the largest phylum of Kingdom Animalia?
Q.14 Name the seven basic hierarchial categories.
Q.15 Mention an organism which exhibits characters of both plants and animals.
Q.16 In which groups are diploblastic animals found?
Q.17 Why are frogs not seen in the winter months?
Q.18 Give one difference between cartilaginous and bony fishes.
Q.19 Name three flightless birds.
Q.20 Name the phylum to which the following belong:
(i) Silver fish (ii) Sea horse
(iii) Sea cucumber (iv) Jelly fish
(v) Devil fish (vi) Star fish
(vii) Cray fish
Short Answer-Type questions :
Q.1 Which organisms are called primitive and how are they different from the so-called advanced organisms ?
Q.2 What is the criterion for classification of organisms as belonging to Kingdom Monera or Protista ?
Q.3 In the hierarchy of classification, which grouping will have the smallest number of organisms with a maximum of characteristics in common and which will have the largest number of organisms?
Q.4 How are pteridophytes different from the phanerogams ?
Q.5 Explain the basis for grouping organisms into five kingdoms.
Q.6 Name the group of plants that belongs to the division Thallophyta.
Q.7 How are the seed-bearing plants further classified ?
Q.8 What is the need of nomenclature ?
Q.9 Draw a flow-diagram to show the five kingdom classification.
Q.10 Give two important characters of bony fishes.
Q.11 What are the four main characteristics of chordates?
Long Answer Question :
Q.1 Write the distinguishing characters of Kingdom Monera, Kingdom Protista and Kingdom Fungi.
Q.2 Describe the diagnostic characters of Algae, Fungi and Bryophyta.
Fill in the blanks :
Q.1 Five Kingdom classification of living organisms is given by ................................ .
Q.2 Basic smallest unit of classification is ..........
Q.3 Prokaryotes are grouped in kingdom ................................ .
Q.4 Paramoecium is a protistan because of its .......
Q.5 Fungi do not contain ................................
Q.6 A fungus ................................ can be seen wihtout microscope.
Q.7 Common fungus used in preparing the bread is ........... .
Q.8 Algae and fungi form symbiotic association called ............. .
Q.9 Fungi show ....................... mode of nutrition.
Q.10 Cell wall of fungi is made up of .............. .
Q.11 ......................... is considered as 'Father of Zoology'.
Q.12 The respiration in insects is by .........................
Q.13 Pore-bearing animals are placed in phylum .........................
Q.14 Tube feet of echinoderms help in ......................... and .........................
Q.15 The structure which separates the thoracic cavity from abdominal cavity in mammals is .........................
Q.16 The largest phylum of the kingdom Animalia is .........................
Q.17 Nematoblasts or stinging cells are characteristic of .........................
Q.18 Organisms which remain fixed to the bottom of the sea or some other object are called .........................
Q.19 In urochodates the notochord is confined to the .........................
Q.20 Birds and ......................... are warm-blooded vertebrates.
TRUE OR FALSE
Q.1 Mosses have a vascular system.
Q.2 Ferns are seedless plants.
Q.3 Fungi reproduce only asexually.
Q.4 Hornworts and liverworts are pteridophytes.
Q.5 Conifers are angiosperms.
Q.6 Bryophytes are distinguished into root, stem and leaves.
Q.7 Lichen is dual organism which shows association of algae and fungi.
Q.8 Algae is included in Kingdom Animalia.
Q.9 Bacteria are prokaryotic.
Q.10 Female sex organs in bryophytes is called ascogonium.
Q.11 All the vertebrates are warm-blooded animals.
Q.12 Duckbilled platypus and spiny ant-eater are egg laying mammals.
Q.13 Kiwi is the smallest flightless bird.
Q.14 Snails and slugs have open circulatory system.
Q.15 Flatworms have true coelom.
Q.16 Whale is largest fish known.
Q.17 Planaria is free-living aquatic flatworm.
Q.18 Sponges have a nervous system.
Q.19 Hydra is a fresh water coelenterate.
Q.20 Crocodiles have four chambered heart.
MATCH THE COLUMN :
Q.1 Match the items of Column A with items of Column B.
A B
(a) Naked (i) Angiosperms
(b) Covered seed (ii) Gymnosperms
(c) Flagella (iii) Bryophytes
(d) Marchantia (iv) Euglena
(e) Marsilea (v) Thallophyta
(f) Cladophora (vi) Pteridophyta
(g) Penicillium (vii) Fungi
Q.2 Match the items of Column A with items of Column B.
Column A Column B
(i) Flightless bird (a) Echinoderm
(ii) Egg laying mammal (b) Snake
(iii) Hydra (c) Birds
(iv) Cnidoblasts (d) Endoparasite of intesine
(v) Pseudocoel (e) Ostrich
(vi) Ascaris (f) Earthworm
(vii) Sea urchin (g) Lamprey
(viii) Jawless vertebrate (h) Shark
(ix) Limbless reptile (i) Duckbilled platypus
(x) Cartilage fish (j) Kangaroo
(xi) Leech (k) Coelenterates
(xii) Millipedes (l) Roundworms
(xiii) Nephridia (m) Segmented arthropods
xiv) Pneumatic bones (n) Hirudin
(xv) Pouched mammal (o) Fresh water coelenterate
Very Short Answer Question :
1. protista
2. Thallophyta
3. (i) Gymnosperm, (ii) Angiosperm
4. Species
5. Cryptogams & Phanerogams
6. Species
7. Rice & Maize
8. Gram & pea
9. Gymnosperm
10. Thallophyta
Fill In The Blanks :
1. Whittaker 2. Species
3. Monera 4. Unicellular eukaryotic nature 5. Chlorophyll
6. Mushroom 7. Yeast
8. Lichen 9. Saprophytic
10. Chitin 11. Aristotle
12. Tracheae 13. Porifera
14. Locomotion, Respiration
15. Diaphragm 16. Arthropoda
17. Coelenterates 18. Sessile
19. Tail 20. Mammals
Write True Or False For the Following :
1. F 2. T 3. F 4. F
5. F 6. F 7. T 8. F
9. T 10. F 11. F 12. T
13. T 14. T 15. F 16. F
17. T 18. F 19. T 20. T
Match the following :
1. (a) – (ii), (b) – (i), (c) – (iv), (d) – (iii),
(e) – (vi), (f) – (v), (g) – (vii)
2. (i)–e, (ii)–i, (iii)–o, (iv)–k, (v)–l, (vi)–d,
(vii)–a, (viii)–g, (ix)–b, (x)–h, (xi)–n, (xii)–m, (xiii)–f, (xiv)–c, (xv)–j