English-Class X-biology-chapter01

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Classification of Plants : Important groups –

Non-Vascular plants – Multicellular Algae –Bryophytes; Vascular plants – Pteridophytes –

Gymnosperms – Angiosperms.

Classification of Animals : Vertebrata – General

Characters; Important classes – Pisces –

Amphibia – Reptilia – Aves – Mammalia.

You have studied the meaning andmportance of classification in your previous class.

You are also familiar with the hierarchy of

classification.

Plants and animals exhibit considerable

diversity at the cellular level. During the evolution

of organisms, diversity has occured in the structure

and functions of the cells. For example, algae are

generally aquatic, and the lower group of algae

are unicellular, filamentous or colonial in their

orms. The higher algae like Kelp and Sargassum

are multicellular. Plants are deep rooted and

widely branched. They have longer life span and

show diversity in reproduction.

You have learnt about the diversity in the

structure and function of the lower plants and

animals in your previous classes. Let us now

study about the classification of higher plants and

animals.

The following scheme represents the major groups of organisms under the

5 kingdom classification :

Diversity of plants and

animalsThe approximate number of speciesso for identified is about 1,672,000.According to modern classificationplants and animals are classifiedinto five major kingdoms Monera,Protista, Mycota, Plantae andAnimalia.

About 9,000 species are identifiedunder Kingdom Monera. The number

of species in Kingdom Protista isabout 59,950. The number ofspecies under Mycota is about100,000. The number of speciesidentified under the KingdomPlantae is about 289,640. The totalnumber of species identified underAnimalia is about 1,170,000.

Major divisions of theKingdom Plantae

Bryophyta - 24,000 species

Pteridophyta - 10,000 species

Gymnosperms - 640 species

Angiosperms - 255,000 species

Remember this

The known number of vertebratespecies under animal kingdom

Pisces - 2,546 species

Amphibians - 204 species

Reptiles - 428 species

Birds - 1,228 species

Mammals - 372 species

1 THE LIVING WORLD



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KINGDOMS

↓

↓ ↓ ↓ ↓ ↓

Monera Protista Mycota Metaphyta Metazoa

(Plantae) (Animalia)

. Bacteria 1. Unicellular 1. Fungi Non Vascular Multicellular AnimalsAlgae Plants (Invertebrates)

2. Blue green 2. Protozoa 1. Multicellular Algae 1. Poriferaalgae 2. Coelenterata

a. Red algae 3. Platyhelminthesb. Brown algae 4. Aschelminthesc. Green algae 5. Annelida

2. Bryophytes 6.Arthropoda7. Mollusca8. Echinodermata

Vascular plants Chordata1. Pteridophytes 1.Pisces2. Gymnosperms 2.Amphibia3. Angiosperms 3.Reptilia

4.Aves5.Mammalia

1.1 MULTICELLULAR ALGAE

You have studied about unicellular algae likediatoms in your previous class. Most of the algaeare multicellular and have a flat plant body calledhallus. These algae are non-vascular plants. Theyare identified under plant kingdam. They areclassified into three groups, namely : Red algae,Brown algae and Green algae.

Ex : Red Algae - Batrachospermum Polysiphonia

Brown Algae - Sargassum, Ectocarpus Green Algae - Spirogyra, Ulothrix

Algae are mostly aquatic. Members of redand brown algae grow attached to rocks, coralsand other plants of the ocean. Members of greenalgae are mostly freshwater forms found in ditches,ponds, lakes and rivers. A few of them are foundn oceans and on lands, or grow attached to otherplants. Algae are capable of carrying out

photosynthesis.

Agar is obtained from a red algacalled ‘Gelidium ’. It is used inbakery and meat packing industry.It is also used as a medium forculturing bacteria.

A red alga called Porpyra is used

as a condiment and in thepreparation of soup.

An alga called Microcystus growsupto 100 feet in length.

Algin is a useful substance obtainedfrom brown alga. It is used in thepreparation of ice cream, chocolates

and in the preparation of a Japanesefood “Kombu”.



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Green algae contain the green pigmentcalled chlorophyll.

In Red algae chlorophyll ‘a’ and ‘b’ pigmentsare found. In addition, a red pigment calledphycoerythrin and a blue pigment called

phycocyanin are found. Hence, the plant bodyshows red colour.

In Brown algae chlorophyll ‘a’ and ‘c’ pigmentsare found. In addition, xanthophyll pigments areound in abundance. Hence, these algae arebrown in colour.

The cellwall of algae is composed of cellulose

and pectin. Usually the cells are uninucleate.

Reproduction takes place both by asexual

and sexual means.

Sexual reproduction takes place by the fusion of male and female gametes.

Asexual reproduction takes place by the production of spores. Vegetative

propagation is by the fragmentation of thallus. Each bit of the thallus will separate

rom the mother plant and grow into a new plant.

Some species of algae arepreserved and used in thepreparation of cattle feed.

The dead bodies of marine algaealong with other dead organisms of

the sea, undergo decay and releasemethane gas.

When algae grow in decaying watertanks, the oxygen liberated will beutilized by microbes and thus watergets purified.

Fig 1.1 - Common examples of green algae

Many types of algae are used inindustrial processes. A giant alganamed Laminaria is used in theproduction of potassium chlorideand iodine.

Cellwall

Chloroplast

Nucleus

Cytoplasm

Spirogyra - A cell enlarged

Cellwall

Nucleus

Cytoplasm

Chloroplast

Ulothrix - A filament



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1.2 BRYOPHYTA

These plants are found both on moist landand in water. Hence, they are commonly calledas amphibians of the plant kingdom.

Bryophytes are multicellular plants having

he features of eukaryotes. The plant body is alattened, thalloid structure and can be differentiatednto stem, leaves and rhizoids. In these plants,oot-like structures called ‘rhizoids’ are present.

Some plants of this group grow horizontallyn the soil. Ex : Riccia (Liverwort) Some plantsgrow vertical to the soil surface. Ex : MossesThey exhibit simple shoot system and leaves).

The common examples of bryophytes are Marchantia, Riccia, Funaria andMosses.

The life cycle of bryophytes includes twosuccessive generations called gametophyte andsporophyte. Gametophytes are gamete producingplants. Sporophytes are spore producing plants.Gametophytes are prominent and larger in sizeand manufacture food with the help of chloroplasts.Sporophytes are smaller in size and depend on

gametophytes for food.

Rhizoids

These are not roots, but only root-like structures. They absorb waterand mineral salts from the soil.

Meaning of ‘Liverwort’

Since the plant body of some of thebryophytes resemble the shape ofliver, they are called ‘Liverworts’

Riccia is a liverwort that occursboth in water and in moist soil. Thegenus includes about 130 species.Marchantia includes about 65species.

Mosses are tiny little plants generallymaking their apearance after the rains.They are found growing on moist walls,tree trunks and on the ground. Whenthey grow in plenty they cover thesubstratum. Mosses found growing onrocks are called rock mosses. Somemosses grow in marshy places and are

called bog mosses.

Fig 1.2 - Common examples of bryophytes

Marchantia : male andfemale plants

Riccia

MossFunaria



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Bryophytes reproduce by sexual and

vegetative methods. During vegetative

eproduction, the thallus breaks into pieces and

each piece grows into a new plant. Sexual

eproduction occurs by the male and female

gametes. Structures called antheridium andarchegonium are found in adult gametophytes.

Male gametes are produced in antheridium, Female

gametes are produced in archegonium.

1.3 PTERIDOPHYTA

Pteridophytes are included in the group

called “tracheophytes”, because they have thevascular tissues (xylem and phloem) to conduct

water and mineral salts. Ferns and other related

plants are called pteridophytes. These are found

n gardens, moist soil, on the walls and in all cool

and shady regions. These are the first terrestrial

plants to develop vascular tissues to transport

ood and water from one part of the plant toanother. The plant body is differentiated into root,

stem and leaves.

Examples : Nephrolepis (fern plant) Selaginella, Adiantum, Lycopodium.

There are two generations in the life cycle namely sporophyte and

gametophyte.

Moss plants are used in packingflowers. In gardens, moss pads areconstructed while growing creepers.

Fig 1.3 - Some examples of PteridophytesSelaginella

Nephrolepis - A fern plant

‘Walking ferns’

Marsilea, Salvenia, Azolla are thefloating ferns of tanks, ponds etc.The leaves of the fern adiantumtouch the ground, develop rootsand become new plants. These arecommonly called ‘Walking ferns’

Ferns are grown for ornamentalpurposes. Fern leaves are used inflower bouquet. Some ferns areused in medicine. Fern plants like

horsetail and club mosses areinvolved in the formation of goodfuels like coal, petroleum etc.



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The adult plant body is a sporophyte. The sporophyte reproduces asexuallyby producing spores. The gametophyte is small but is an independent structurecalled prothallus. Male gametes are produced in antheridium and female gametesare produced in archegonium, both found in the prothallus.

Sexual reproduction involves the fusion of male and female gametes.

1.4 GYMNOSPERMS

Gymnosperms are a group of seed-bearing vascular plants. However, seedsare not enclosed in fruits.

Gymnosperms grow in dry but cold climatic regions. These are perennialand evergreen plants. Ex : Cycas, Pinus.

Some plants of this group are large treesand some are shrubs. The vascular system is welldeveloped with xylem and phloem. The mostprominent feature of these plants is the productionof two kinds of spores namely microspores andmegaspores. They are produced in structurescalled microsporophylls and megasporophyllsespectively.

Meaning of gymnosperms

In Greek - Gymnos = naked

Sperma = seed

Plants having ‘naked seeds’

Cedrus deodara is a gymnosperm.It grows in the Himalayan forests.

Cupresus, Aracaria juneferous and Cycas are grown in gardensfor ornamental purposes.

Sequoia tree grows about 125meters in height and is about 30meters in circumference.

Fig 1.4 - Cycas - A gymnosperm

Cycas :Male plant

Cycas Female plant

Hood

Ovule

Stalk

megasporophyll

Cycas :Microsporphyllsin the male

cone

It is believed that the life span of pinetrees is more than 5000 years. TheBristle cone trees (Pinus aristata ) ofNevada Mountains, U.S.A., are knownto be more than 5,000 years old.

Coniferous trees are the largest, tallestand oldest trees of the world.



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These plants produce multicellularstructure called cones (They are called conesbecause of their shape). They are of twoypes namely male and female cones.

Microsporophylls produce male sex cells and

megasporophylls produce female sex cells.Sexual reproduction involves the fusion ofhese cells to form a ‘zygote’. The zygote iscovered by a thick coat and together theyepresent the seed.

1.5 ANGIOSPERMS

Angiosperms are the most evolved amongplants. In these plants, the seeds are enclosedn a structure called fruit.

Angiosperms are commonly called as flowering plants. They are found inmoist soil, desert, fresh water habitats. Ex : Maize, Coconut, Wheat, Paddy, PearlBarley, Millet, Mustard, Horsegram, Red Gram, Bean etc.

Based on the general organization of the plant body, angiosperms can begrouped into herbs, shrubs and trees.

Vascular tissues are well developed. Flowers are the reproductive organs.Flowers may be produced singly in the axil of the leaf or a cluster of flowers

may be found together. A special branch bearing a cluster of flowers is callednflorescence.

Fig 1.5 - Male and Female cones

of Pinus

male conefemale cone

Meaning of angisoperms

In Greek Angion = capsule

Sperma = seed

The seeds of orchids are very small.The weight of one million seedstogether is only about 0.3 grams.

Flower

Fruit

Petiole

Stem

Root

Femaleflower

Male flowers

Leaf

Stem

Roots

Fruit

B. Maize plantA. Mustard plant

Fig 1.6 - Typical Dicot (A) and Monocot (B) Plants

Leaf



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Seeds are produced in flowers. Seeds are

of two types. 1. Monocotyledonous2. Dicotyledonous. Monocot seeds contain only

one cotyledon (seed leaf) while the dicot seeds

contain two cotyledons. In monocots, during

germination the cotyledon remains below the soil.

n dicots the cotyledons appears above the soil.

In monocot leaves, veins run parallelly. In

dicot leaves, veins are found in the form of anetwork.

Monocot plants have fibrous root system,while dicot plants have tap root system.

What is Bonsai?

The technique of growing dwarf treesis called bonsai. This technique being

the invention of Japanese helps togrow orange, lime, banyan and mango

trees etc. in pots as dwarf trees. Thetrees grown by this method will beof the same height even after 20-30years. They also bear fruits andflowers.

Stigma

Style

Stamen

Petal

Sepal

Ovary

Fig 1.7 Parts of a typical flower

Common trees of Karnataka

Teak, Blackwood, Jackfruit, Nandi,

Honne, Jamun, Sandal, Cinnamon,Red dye tree, Presin, Indian Mast,Gooseberry, Indian beach, Babul,Acacia, Mango, Tamarind andBamboo are some of the commontrees of Karnataka.

Do you know about thespeciality of sandal trees?

Sandal wood tree is an economicallyimportant tree. The scientific name ofthis tree is ‘Santalum album ’. Theroots of this tree are attached to theroots of other plants and absorb therequired food material. The roots areused in treating skin diseases. Sandalcarving is a beautiful art and materials

made out of it are world famous.Sandal oil is also used in themanufacture of scents and oils.

(A)

Parallel venation inmonocot leaf

Fig 1.8 - Venation in angiosperm leavesMonocots are more advanced thandicots from the point of view ofevolution. About 200,000 dicot plantspecies and 55,000 monocot plant

species are identified.

(B)Reticulate venation in

dicot leaf

{PISTIL



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In fibrous root system, the primary root diesbefore the plants mature. Roots develop from thebase of the stem and branch profusely. A singlemain or central root is absent.

In taproot system, the primary root from theadicle of the seed grows to become the main

or central part of the root system. It produces

many secondary and tertiary branches.

1.6 VERTEBRATES

Vertebrates represent a major group among the advanced animals calledchordates. Chordates exhibit the following characteristic features.

. Presence of a solid supporting structure on the dorsal side of the bodycalled notochord.

2. Presence of a dorsal, tubular nerve cord.

3. Presence of openings in the pharynx called gillslits, atleast in the embryonicstages.

Those chordates in which the notochord is replaced in the adult by avertebral column are grouped under vertebrata. All other animals other thanchordates, are described as invertebrates or non-chordates.

You have studied about invertebrates and their classification in your previousclass. Now, we shall study about vertebrates and their classification.

StemSome useful Plants

Vegetable yielding plants

Brinjal, Ladiesfinger, Cucumber,Potato, Onion, Lemon, Gooseberry,Green leafy vegetables.

Oil yeilding plants

Castor, Groundnut, Sun flower, Niger,Ginger,

Fibre yielding plants

Cotton, Jute, Hemp

Spice yielding plants

Coriander, Fenugreek Cumin,Mustard, Pepper, Cardamom, Clove,

Turmeric.

Fruit yielding plants

Banana, Grapes, Apple, Mango,Guava, Water melon

Fodder yeilding plants

Maize, Jowar, Ragi, Paddy, Grasses.

Medicinal plants

Leucas aspera, Ginger, Ocimum

(Tulsi) Eucalyptus, Neem

Bevarages

Tea, Coffee, Cocoa

Fig 1.9 - Types of roots in angiosperms

Stem

Tap root

Fibrous roots

(A) Tap root system (B) Fibrous root system



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Vertebrates are characterised by the

presence of a backbone or vertebral column

which forms a major component of the skeletal

system. The skeletal system consists of hard rigid

structures called bones which provide support to

he body. They also provide surface for theattachment of muscles.

The body is divided into head, trunk and

imbs.

Digestive system consists of mouth, pharynx

oesophagus, stomach, intestine and many

associated glands.

Respiratory organs are well developed. They

are in the form of gills in aquatic forms and lungs

n terrestrial forms.

Heart is ventral in position and is chambered. Excretory organs are in the

orm of a pair of kidneys. Nervous system consists of dorsal tubular nerve cord

which becomes differentiated into brain and spinal cord.

Vertebrates are unisexual. Only sexual reproduction is seen.

Vertebrata is grouped into the following 5 classes.

(1) Pisces (2) Amphibia (3) Reptilia (4) Aves (5) Mammalia

1.61 PISCES

The members belonging to this class are

commonly called fishes.Fishes are aquatic vertebrates with a

streamlined or spindle shaped body. Mouth is athe terminal end of the body. Jaws are providedwith teeth. Skin is covered with scales whichprovide protection. Skin contains mucous glands.Locomotor structures are in the form of paired

and unpaired fins. Paired fins help in balancing

also.

Meaning of chordata

In Greek, Noton = Back

Chorda = Supporting rod

The animals having a dorsalsupporting rod-like structure.

Meaning of vertebrataVertebrae = Series of bones

Vertebrata - Animals having avertebral column

Phylum chordata includes about39,000 species. This is the mostadvanced phylum in the animal

kingdom

Members of the phylum chordatavary in size from fishes less thanhalf an inch, to whales which areapproximately 30 meters in lengthand 150 tons in weight.

Meaning of pisces

In Greek - Pisces means fish

Migration of fishes

The migratory eels travel thousandsof kilometers from Europe to westor from America to east to theirbreeding centres.



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Economic importance of fishes

Many fishes are consumed as food.Oils are obtained from the livers ofshark and cod. These oils are richin vitamins ‘A’ and ‘D’. The driedskin of sharks is used in makingpolishes.

Fig 1.10 - External features of a fish

Nostril

Eye

Dorsal fin

Mouth

Gill cover Pectoral fin(Paired)

Anal fin

Caudal fin

Pelvic fin(Paired)

Sea horse

Ray fish

Flying fish

Saw fish

Hammerheaded fish

Sucker fish

Shark

Fig 1.11 - Types of Fish

Do you know about fish

which do not look like fish?

The body shape of fish is familiarto us. But there are some fish whichdo not look like fish. A familiarexample is Hippocampus . Its snoutresembles the face of a horse,Hence, it is called sea horse. It has

an elongated body and long coiledtail. Sea horse swims vertically.

Strange fishes

A fish called Ostracion has a pairof horns in front of head and eyes!Hence, it is commonly called “Cow

Fish”

Production of electricity infishes

The electric ray fishes have anorgan to produce electricity. Theseorgans produce high voltage currentin the surrounding water. The electric

eel of Amazon can produce anelectricity of 200 volts!



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Digestive system is well developed with an alimentary canal and associated

glands.

Respiration is typically by pharyngeal gills. Heart is two chambered. Fishes

are cold blooded (poikilothermic) animals. Nervous system is well developed

with brain and spinal cord. Internal skeleton is either cartilagenous or bony. Theseare unisexual animals. They reproduce sexually. There is a great diversity in

colour, shape and structure among fishes.

Ex : sharks, saw fish, electric ray fish, hippocampus (sea horse)

1.62 AMPHIBIA

Members of this class are commonly calledamphibians. Amphibians are the first vertebrates

o appear on land. They are adapted living

successfully on both land and in water.

The body is divisible into head, trunk and

imbs. The skin is very soft and moist due to

secretion of mucous glands. Mouth is provided

with jaws. Nostrils are exposed above the mouth.

Fore limbs have four digits while hind limbs have

ive digits each.

Some amphibians are limbless.Ex : Ichthyophis.

Meaning of amphibia

In Greek - Amphi = both

bios = Life

The animals live both in water andon land.

Because of the secretion of mucusin amphibians the skin is always

kept moist. It helps in respirationalso.

Hibernation and Aestivation(Winter sleep and summer

sleep)

In cold weather and in very dryperiods frogs bury themselvesunderground in damp places. These

periods of inactivity are termedhibernation and aestivationrespectively. During these phasesof their life they do not take foodand live only on the stored fat.

Parental care

A toad called Alytes of Europecarries the egg around its hind legstill the tadpoles are about to hatch.

Nostril

Eye

Mouth

Forelimb

Webbed

feet

Hind limb

Fig 1.12 - External features of frog



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It has well developed digestive system with alimentary canal, and associated

glands. Respiration is by gills, skin, buccal cavity and lungs. A three chambered

heart is found. Amphibians are also cold blooded animals. Nervous system is

well developed with a brain, a spinal cord and 10 pairs of cranial nerves and

an autonomous nervous system.

These are unisexual animals. They reproduce sexually. Fertilization is

external.

They lay eggs on stagnant water.

Metamorphosis’ is seen in the life cycle of these

animals. Ex : Frog, Toad, Salamander, Ichthyophis

etc.

1.63 REPTILIAMembers of this class are commonly called

eptiles. These are the first terrestrial vertebrates.

They have an elongated body covered by a dry

skin bearing an exoskeleton of horny scales. Both

orelimbs and hindlimbs have five digits each

pentadactyle).

Some of the reptiles like snakes, are limbless.

Do you know this?

A toad called Pipa of America doesnot have tongue. These toads havenumerous pits on their back andcarry their young ones in the pits.

Ichthyopis is an Amphibian found inburrows. The skin is soft providedwith folds. The female lays eggs inthe soil and coils round her eggsand protect them till they hatch.

Ichthyophis

Salamander

Fig 1.13 Examples of Amphibia

Metamorphosis

The changes which a larva

undergoes in order to become anadult are collectively calledmetamorphosis

Meaning of reptilia

In Latin - repere = to creep

creeping or crawling vertebrates.

External Fertilization

Fertilization takes place in watermedium, outside the body.



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Do you know aboutChameleons?

Chameleon is a lizard. Eyes arecapable of independent movement.This lizard is known for changingits body colour with thesurroundings. It is a self defenceMechanism to escape from itsenemies.

Eye

Fore Limb

Hind Limb

Tail

Fig 1.14 - External features of a garden lizard

Extinct reptiles

Tyranosaur and Dinosaur are thegiant reptiles which existed about150 million years back and areextinct now.

Crocodile

Snake

Chameleon

Tortoise

Tyranosaurus

Fig 1.15 - Some examples of reptiles

Poikilothermic animals (coldblooded animals)

These are animals in which thebody temperature keeps changingaccording to changes in thesurrounding environment.



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Digestive system consists of mouth, pharynx, oesophagus, stomach, smallntestine, large intestine and associated glands.

Respiration takes place through lungs.

The heart is three chambered. The heart is more evolved than inAmphibians. Reptiles are also cold blooded animals.

Nervous system consists of a brain a spinal cord and 12 pairs of cranialnerves.

Reptiles are unisexual animals. They reproduce by sexual methods. Alleptiles are egg laying (oviparous) animals. Ex : Chameleon, Snake, Tortoise,

Crocodile, House lizard etc.

1.64 AVES

Members of this class are commonly called

birds. They are found in different habitats likewater and land.

The body is covered by feathers. Feathersare diversified with various colours. They performvarious functions like protection, help in maintainingbody temperature and loss of water. Feathersalso help in sexual attraction. In birds, forelimbsare modified into wings which help in flight.Depending upon the habitats of different birdshindlimbs are variously adapted for runningwalking, swimming and wading.

The body is very light and the bird can flywithout friction. The bones are hollow, light andilled with air. Such bones are called pneumaticbones.

Meaning of aves

In Latin - Avis - Birds

The smallest bird

Humming bird is the smallest birdwhen it is developed completely, itweighs about 3 grams! It can alsofly backwards!

The biggest bird

The male Ostrich grows about 2.4meters in height and weighs about

140 kgs. It can run at a speed of60 kms per hour.

Warm blooded animals

(Homeothermic)

The animals which do not fluctuatetheir body temperature with changesin the environmental temperatureare called homeothermic animals.In these animals body temperature

remains contant.

Fig 1.16 - External features of a bird

Migration in birds

Arctic tern, a nonstop migratorybird can travel to a distance of18,000 kms.

Syrinx-the Voice Box

The voice box which has vocalcords is streched across and

responsible for the production ofSound.

Wing feather

Leg

Eye

Wing

BeakTail feathers



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Lungs are specialized for storing excess air. The voice box or syrinx isound at the base of trachea.

A four chambered heart is present. Birds are active warm blooded

homeothermic) animals. Heart beat is very rapid than other animals.

Nervous system is more evolved than in reptiles. 12 pairs of cranial nerves

are found.

Birds are unisexual, reproduce by sexual methods. All are oviparous andeggs are covered by calcarious shells.

Ex : Ostrich, Parrot, Hawk, Pigeon, Penguin, Flamingo, Arctic tern etc.

1.65 MAMMALIA

Members of this class are commonly called

Mammals. The animals bear mammary glands toeed their young ones.

Heart beat in birds

The rate of heart beat and sizeof the heart in birds varies with

the size and activities of birds.In Turkey heart beat may beless than 100 per minute.

In hens, the rate of heart beatmay be 300 per minutes. Insparrow it may be 500 perminute. In some smallestspecies of birds, it may be upto

1,500 beats per minute.

Meaning of mammalia

In Latin, - Mamma = Breast

The animals having mammaryglands

Peacock

King fisher

Kiwi

PenguinGray horn Bill

Tern

Pelican

Flemingo

Myna

Ostrich

Fig 1.17 - Common examples of Birds

Kiwi



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These are the most evolved animals in theanimal kingdom. The skin is covered by hairs

Mouth is provided with jaws bearing teeth. The

eyes have movable eyelids and eyelashes. Ear has aleshy external pinna. Limbs are pentadactyl, endingn claws or nails.

Smallest mammal

‘Pigmy Shrew’ is the smallest

mammal weighing only about 2.5grams

Biggest Mammal

The Blue Whale is the largest knownaquatic mammal. It is nearly 30 meterslong, 200 Metric tons in Weight.

An architect of the animalworld

The mammal called Beaver isan excellent architect of theanimal world. An illustrationobtained about the intelligence

of these animals is that theyconstruct dams near theirshelter. They make use ofstones and tree trunks andconstruct dams along the pits

near their shelter and they evenconstruct reservoirs!

ForelimbHind limb

Mouth

Eye

Hairy Skin

Tail

Fig 1.18 - External features of a typical mammal - rat

Ear

Kangaroo is the native mammal of

Australia. It has a pouch(massupium) formed by a fold skin

on the lower part of body below thestomach. The young ones are rearedin this pouch.

Bat

Giraffe

Elephant

Panda

Lion

Kangaroo

Platypus

Echidna

Whale

Fig 1.19 - Some common examples of mammals

The mammal sloth walks and

sleeps upside down

Viviparous animals

Animals giving birth to young onesare called Viviparous animals

Egg laying mammals

The duck-billed Platypus, the spinyant eater Echidna are the only twoegg laying mammals.

Bat is mammal capable of trueflight.



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Respiration takes place through lungs. The thoracic and abdominal cavitiesare separated by a muscular membrane called the ‘diaphragm ’

The heart is four chambered with two auricles and two ventricles.

The nervous system is more evolved than other vertebrates. It consistsof brain, spinal cord, cranial and spinal nerves.

Mammals are unisexual animals. Reproduce by sexual methods. Mostmammals give birth to young ones except echidna and platypus. They are eggaying mammals.

Ex : Kangaroo, Whale, Bat, Giraffe, Lion, Elephant, Man etc.

After studying this unit you will ................

. recognise the important characteristics of various groups of non-vascularand vascular plants and also various groups of vertebrates.

2. cite examples for the important groups of non-vascular and vascular plantsand also for the 5 classes of vertebrates.

3. compare the characteristic features of lower plants with that of higher plants.

4. recognise the increase in complexity in the body structure from lower groupto higher groups of vertebrates.

5. appreciate the diversity among the animal groups.

Activities

. Try to visit plant nurseries, botanical gardens, zoos, natural history

museums, protected forests to note the natural habitats of flora and fauna,characteristic features of organisms both in natural and aritifcial conditions.

2. Prepare an album of pictures and photographs of various groups of plantsand animals, collected from sources like magazines, journals, specialcoverages in newspapers.

3. Join a planned field trip under the guidance of your teachers and try tocollect specimens for display in science room/laboratory.

EXERCISES. Choose the correct answer from the following

1. The brown alga among the following is .....................

a) Polysiphonia b) Sargassum c) Spirogyra d) Ulothrix

2. The multicellular cone like structures are found in ..................

a) Gymnosperms b) Bryophytes c) Pteridophytes d) Algae.

3. Two chambered heart is found in .................

a) Pisces b) Reptiles c) Amphibians d) Aves



4. The number of chambers in the heart of birds are ................

a) Four b) Two c) Three d) One

5. An egg laying mammal among the following is ...............

a) Bat b) Giraffe c) Platypus d) Kangaroo

I. Answer the following questions :1. Mention any two salient features of multicellular algae

2. List any two important characteristics of bryophytes.

3. Differentiate between a gametophyte and a sporophyte.

4. Why are pteridophytes called tracheophytes?

5. List any two important characteristics of gymnosperms

6. List any two characteristics of angiosperms?

7. What is an inflorescence?8. Mention any two general features of vertebrates.

9. What are amphibians? Give an example.

10. What is external fertilization?

11. In which animals do you find metamorphosis?

12. Mention any two salient features of reptiles?

13. List out any two salient features of birds?

14. Mention any two salient features of mammals?15. What is prothollus?

16. What are cones?

17. What are pneumatic bones?

II. 1. Draw a neat labelled diagram of a fish.

2. Draw a neat diagram of ulothrix cell and label the following parts.

a) Cell wall b) Nucleus c) Cytoplasm d) Chloroplast

3. Draw a labelled diagrams of taproot and fibrous root systems.

V. Match the following

A B

1. Pisces a. Tortoise

2. Ambhibian b. Platypus

3. Reptile c. Sea horse

4. Aves d. Ichthyophis

5. Mammal e. Arctic tern

English-Class X-biology-chapter01

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