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2   BIOLOGICAL DIVERSITY

Important points to remember : 2.

 BIOLOGICAL DIVERSITY

1. Biological diversity : Thousands of living things exist on the

earth. The variety seen among these living things is known as

biological diversity or biodiversity.

2. Examples of biodiversity : (1) There is great diversity in size

and shape of the living things. There is diversity ranging from

microorganisms, unicellular plants and animals to giant trees,

vines, huge animals like whale and elephant. (2) There is

tremendous variation in the eating habits of animals. (3) Factors

that transmit chromosomes from one generation to the next

generation differ in different organisms. (4) Variation (variety)

is also seen in body structure, habitat and life patterns of the

living organisms belonging to the same class.

3. Biodiversity and environment : Environment is an important

factor that brings about the biodiversity. Due to constant

changes in the environment there are variations among the

living organisms. e.g. (1) Aquatic organisms living in fresh

water ponds, lakes, rivers or in seas exhibit variation. (2) Organisms

living in deserts and those living in coastal regions are

different from each other. (3) Animals and plants from

snowbound regions differ from those living in plains.

4. The Importance of conservation of biodiversity : Human

beings’ basic necessities such as food, clothes and shelter as well

as medicines are met with, because of the biodiversity.

Therefore biodiversity should be conserved.

5. Environmental Importance : Due to biodiversity, in nature

there are producer plants, herbivores, carnivores and

decomposer bacteria. All these form a food chain in nature. Due

to prey-predator links there is always a balance in the nature.

6. Reasons for the decline in the biodiversity : (1) The rate at

which population explosion is taking place in our country is the

main reason behind decline in biodiversity. (2) Single crop

method of agriculture has endangered the biodiversity among

the plant kingdom. (3) Due to the entry of hybrid and imported

varieties of breeds, local breeds are replaced. (4) Cutting down of

the trees (5) Hunting of the animals. (6) Clearing off the land by

cutting vegetation and utilizing it for human habitation.

(7) Building dams, roads and factories. (8) Mining operations

(9) Unbridled consumption of natural resources.

(10) Destruction of habitats rich in biodiversity. (11) Pollution

in the environment. (12) Rising temperatures of the earth

(global warming) and climatic changes.

7. Protection of rare species : (1) It is very important to protect

rare plant and animal species. (2) Laws have been enacted to

protect animals and plants of endangered species. (3) Creating

National Parks and Wildlife Sanctuaries. (4) Formation of

Reserved Biodiversity Zones. (5) Specific and rare species to be

nurtured through special projects. (6) Zoological and botanical

gardens to be established for nurturing rare species of animals

and plants respectively. (7) Compilation and documentation of

traditional knowledge.

8. Conservation of biodiversity through biotechnology : Local

species have characteristics such as resistance to disease,

survival in adverse conditions and shorter life cycles. These

species and the new varieties can be crossed with each other and

the desirable characteristics can be preserved. Seed banks and

gene banks can be helpful for such purpose. Thus biotechnology

helps in conserving biodiversity.

9. Reserved biodiversity zones : These are the areas in which

wildlife is protected, but local people are allowed to carry out

their daily activities.

10. The treaty regulating import and export of all kinds of wildlife

came into existence in 1975. By this treaty wildlife is protected

from international trade.

At Rio-de-Janeiro in Brazil ‘Earth summit’ took place in

1992. The treaty which emphasizes the need for nurturing and

protecting biodiversity was adopted there.

Questions and Answers

Q. 1 Answer the following questions :

* (1) What is meant by biodiversity ?

Ans. Thousands of species of plants and animals exist on the

earth. There is abundant variety in their shapes, sizes and body

parts. This variety in the living things is known as biodiversity or

biological diversity.

* (2) In what respects do the living things differ ?

Ans. Living things differ in the following respects :

(1) Shape and size : Microorganisms and unicellular plants

and animals are very small, while the elephants, whales and trees

are huge in size. There is great diversity in the size of the living

things on the earth.

(2) Body structure and life processes : There is variation in

body structure, systems, organs and in life processes of different

living organisms.

(3) Eating habits : There is tremendous variety (variation) in

the eating habits of different living organisms.

(4) Habitat and environment : The habitat in which

organisms live are varied. Living things belonging to the same class

also have different habitats.

(5) The factors that transmit chromosomes from one

generation to the next generation also show variations.

(3) What kind of variation is seen in fishes ?

Ans. Variation among fishes :

(1) Fishes show great variety in their size. Some fishes are tiny

while some are giant sized. (2) Some species of fish live in fresh

water while some live in saline water. (3) Tail fin of some fish is

used for changing directions while swimming, while some fish use

the same as organ of defence. (4) Some fishes live for a long period

of time as they have long life span, while others may have shorter

life span. These are the variations seen in the body structure,

habitat and life span of different fish.

(4) Why is there a variation in the living things which live

in the same environment?

Ans. (1) Environment constantly changes even if it is from the

same geographical region. (2) These changes take place from time

to time and also from place to place. (3) That is why there is a

variation in the living things which live in the same environment.

* (5) What is the importance of biodiversity ?

Ans. (1) Biodiversity is important for the existence of living

things. (2) The needs of all living things are met due to biodiversity.

(3) Basic necessities of human beings such as food, clothing and

shelter are met with, because of biodiversity. (4) The balance

between producers, herbivores, carnivores and decomposers can

be maintained in nature due to biodiversity. (5) Biodiversity is

important for any kind of environment. (6) Nature’s foodchains

continue to survive due to biodiversity.

* (6) What are the different reasons for the reduction of

biodiversity ?

Ans. The reasons for the reduction of biodiversity are as

follows :

(1) The explosive rate at which population of our country is

growing is the main reason for the decline in the biodiversity.

(2) Due to increase in demand of foodgrains, farmers are using

single crop method of farming. This reduces the biodiversity among

the plant kingdom.

(3) Crops giving bigger harvest and higher prices are mostly

cultivated to large extent. This reduces the diversity of crops.

(4) Hybrid and imported breeds of cattle have replaced the local

breeds of cattle. The local biodiversity of cattle is thus threatened.

(5) Certain varieties of plants are becoming less due to cutting.

(6) Certain species of animals are hunted and therefore their

diversity is dwindling.

(7) The housing and industrial development has caused more

and more demand for clear land. This has resulted in clearing of

the forests.

(8) Huge construction works like dams, roads, factories and

mining destroy natural habitats and thus reduce biodiversity.

(9) Environmental pollution, increase in the temperature of

earth and climatic changes result in the decline in the biodiversity.

* (7) List the various efforts being made to protect

endangered species.

Ans. Following efforts are being made to protect endangered

species :

(1) Laws have been made for the protection of rare species of

plants and animals.

(2) National Parks and Wildlife Sanctuaries are created for the

protection of animals and plants.

(3) Certain areas are declared as Reserved Biodiversity Zones.

 (4) To nurture specific species, special projects have been

undertaken.

(5) Some species of plants are nurtured in Botanical gardens

while those of animals are taken care of in zoos.

(6) Traditional knowledge is compiled and documented.

(7) People’s participation is obtained in protecting and

nurturing biodiversity.

(8) Through biotechnological practices, seed banks and gene

banks are established which conserve the genes of local varieties of

living organisms and thus it helps in conserving biodiversity.

(9) Local species are hybridized with new ones to preserve

important characters.

(8) Describe the treaty made for the conservation of

biodiversity.

Ans. (1) The treaty for conserving biodiversity was adopted at

Earth Summit. (2) Earth Summit was the conference held at Rio-de-

Janeiro in Brazil in 1992. (3) The need for nurturing biodiversity

was emphasized by this treaty.

* (1) What is the special feature of the musk deer ?

Ans. A scented substance called musk is found in the

navel of the musk deer. It has medicinal uses.

* (2) Where is the kangaroo found? What is its special

feature ?

Ans. Kangaroo is mainly found in Australia. The female

kangaroo has a pouch on its abdomen. This pouch is called a

marsupium. Inside the marsupium the young one completes its

growth. Kangaroo is therefore called a marsupial animal. It feeds

its young one through mammary glands. Kangaroo is a mammal.

* (1) What are the uses of chandan (sandalwood) tree ?

Ans. The bark of chandan or sandalwood tree has

medicinal properties. The paste made out of this is used as a

cosmetic. Sandalwood also has anti-inflammatory and

analgesic (painkiller) properties. The oil extracted from

sandalwood bark is used in manufacturing soaps, perfumes,

candles, agarbattis, cosmetics and medicines. Decorative

articles and jewellery are also carved from sandalwood.

Sandalwood paste is also used in puja which has religious

importance.

* (2) What priceless treasure do adivasis possess ?

Ans. Adivasis have a treasure of traditional knowledge

about plants and animals. It is important to preserve this

knowledge. Otherwise, in the course of time, this knowledge,

and biological diversity associated with it, will be lost.

* Q. 2 Write short notes on the following :

(1) Importance of the environment (2) Biotechnology

(3) Reserved Biodiversity Zones.

Ans. (1) Importance of the environment : (1) There are

many organisms in any environment. (2) Among them some are

producers. These are plants. Some are herbivores and some are

carnivores. There are also decomposer bacteria. (3) There are

interactions between these organisms. (4) The prey-predator links

are established between them. (5) These links and foodchains can

exist only if all the organisms are in a balance. (6) Predators are not

able to survive in the absence of prey. If any one of these dies, the

other too also perishes. (7) Biodiversity is maintained due to these

interactions in the environment.

(2) Biotechnology : (1) Biotechnology is the new advancing

field of science. (2) Rare and endangered species are protected with

the help of biotechnology. (3) Local species show many favourable

characteristics such as resistance to disease, survival in adverse

conditions and shorter life cycles. (4) These local species are

crossed with new ones to get the advantage of such characteristics.

(5) For this, strains of local species have to be preserved carefully.

For this purpose seed banks have been established. (6) Gene banks

have also been started to preserve the advantageous genes of the

local varieties. In this way biotechnology is used for preserving

biodiversity.

(3) Reserved Biodiversity Zones : (1) Reserved Biodiversity

Zones are the areas maintained for the conservation of biodiversity.

(2) In such areas, wildlife is given protection. (3) Local people are

permitted to carry on their daily life and work in such areas.

Q. 3 Distinguish between the following :

(1) Seed banks and Gene banks.

Ans. Seed banks Gene banks

1. In seed banks, strains of local	1. In gene banks, genes of local
varieties are preserved.	varieties are preserved
2. Seed banks are established	2. Gene banks are established
with the help of people’s	due to advances in the field of
participation.	biotechnology.

 (2) Sanctuaries and Reserved Biodiversity Zones.

Ans. Sanctuaries Reserved Biodiversity Zones

1. All the forms of life are	1. In sanctuaries wildlife is
equally protected in Reserved	protected. A particular
Biodiversity Zones	species of animal or plant can
	be given special concern.
2. Local people are not allowed	2. Local people are not allowed
to undertake their activities	to undertake their activities
in the sanctuary	in the sanctuary

 Q. 4 Give scientific reasons :

(1) There is abundance of biodiversity on the earth.

Ans. (1) Many varieties of living organisms exist on the earth.

(2) Thousands of species of plants and animals of different

characters coexist on the earth. (3) There is an abundance of

variety in their shapes, sizes and body parts. Thus we have

abundance of biodiversity on the earth.

(2) Environment is an important factor in the biodiversity.

Ans. (1) Environment constantly changes in the course of

time and from place to place. (2) Due to this there is variation

among the living organisms, even though they are living in the

same environment. (3) This produces diversity among the various

life forms. Environment, therefore, is an important factor in the

biodiversity.

(3) Biodiversity should be conserved.

Ans. (1) All living things and human beings fulfill their needs

due to biodiversity. (2) Our basic needs such as food, clothing and

shelter are met with, only due to biodiversity. (3) Other important

necessities such as medicines are also supplied through diverse

plant forms. (4) Biodiversity is important for existence of living

forms. Biodiversity, therefore, should be conserved.

* (4) It is very important to preserve the prey and predator

chains.

Ans. (1) Herbivores are preys while carnivores which feed on

them are predators. (2) Predators cannot live in the absence of their

prey. (3) If any one of these die the other also cannot survive.

(4) For example, tigers will survive only if their prey animals are

available in a jungle. (5) If the herbivores are not there then the

tigers will die due to starvation. Therefore, it is important to

preserve the prey and predator chains to keep the environment in

balance and maintain biodiversity.

* (5) The single crop method can prove harmful.

Ans. (1) Due to increasing population, there is more demand

for foodgrains. (2) Therefore, farmers have started using single

crop method for growing crops. (3) By such method, there is bigger

harvest and higher income for the farmers. (4) But this gradually

replaces multi crop farming which was a traditional method.

(5) Due to this, biodiversity among crop species is reduced. The

single crop method, therefore, can prove harmful.

(6) The local breeds of the cattle are threatened.

Ans. (1) Hybrid and imported varieties of cattle are more

useful than the local varieties. (2) Therefore, more and more

foreign breeds are being used. (3) These breeds are gradually

replacing local breeds. Due to this, local breeds are threatened.

(7) Due to construction work and mining, biodiversity is

threatened.

Ans. (1) For the construction of huge dams there is a need of

clear land. (2) For this purpose the lands which have rich forest

wealth are cleared by cutting away the vegetation. (3) In mining,

there is unbridled consumption of natural resources. (4) The

habitats rich in biodiversity are destroyed during mining

operations. (5) Therefore, by destruction of forest wealth and

vegetation, biodiversity is destroyed. In this way, due to

construction work and mining, biodiversity is threatened.

 (8) Biodiversity is declining due to climatic change.

Ans. (1) Due to changes in climate, the temperature of the

earth is rising. (2) This rising temperature of the earth is

dangerous for some rare and endangered species. (3) Climatic

change also produces large scale changes in the natural habitats.

(4) Environmental pollution also causes climate change. (5) All

these factors cause decline in biodiversity.

Q. 5 Answer the following questions in one sentence

each :

(1) What kind of variety is seen in the living things that

belong to the same class ?

Ans. There is variety in the body structure, life patterns and

habitats of living things that belong to the same class.

(2) What is the use of tail fin for the fish?

Ans. Some fish use tail fin as weapon to defend themselves,

while some use it to change the direction while swimming.

(3) What is the main reason for decline in biodiversity in

India ?

Ans. The explosive rate at which the population is growing is

the main reason for the decline in biodiversity in India.

(4) Why are local varieties of cattle threatened?

Ans. Due to the entry of hybrid and foreign breeds of cattle,

the local varieties are threatened.

(5) Why are large scale changes occurring in the natural

habitats ?

Ans. Large scale changes in the natural habitats are taking

place due to climatic changes.

(6) What is preserved in the gene banks ?

Ans. Genes of local varieties of animals and plants are

preserved in the gene banks.

(7) What is meant by Reserved Biodiversity Zone ?

Ans. Reserved Biodiversity Zone is the area where wildlife is

protected but the local people staying there are permitted to carry

on their daily routine.

(8) Which event was organized at Rio-de-Janeiro in

Brazil ? When was it organized ?

Ans. The Earth Summit was organized at Rio-de-Janeiro in

Brazil in 1992.

Q. 6 Find the odd man out and give reasons :

(1) Elephant, Whale, Tree, Shrub.

(2) National Parks, Sanctuaries, Reserved Biodiversity Zones,

Dams.

(3) Recreation, Food, Shelter, Clothing.

(4) Snowbound regions, Lifestyle, Habitat, Body structure.

(5) Polar bear, Yak, Snow leopard, Camel.

Ans. (1) Shrub. Others are huge in size. (2) Dams. Others are

places reserved for the protection of wildlife. (3) Recreation.

Others are basic necessities of man. (4) Snowbound regions.

Others are factors responsible for biodiversity. (5) Camel. Others

are animals living in snowbound regions.

Q. 7 Considering the correlation between the words of

the first pair, match the third word with the most appropriate

answer :

(1) Unicellular : Microorganisms : : Whale : ………

(2) Carnivore : Predator : : Herbivore : ………

(3) Plant : Producer : : Bacteria : ………

(4) Zoological gardens : Animals : : Botanical gardens : ………

(5) Disappearance of species : Environmental pollution : :

Unbridled consumption of natural resources : ………

(6) Import and export of wildlife : Protection of wildlife by

International trade treaty : : Protection of biodiversity :

………

Ans. (1) Huge animal (2) Prey (3) Decomposer (4) Plants

(5) Mining (6) Biodiversity treaty.

Q. 8 State whether the following statements are True or

False. If a statement is False, correct it and rewrite :

(1) Thousands of species of only plants can be seen to exist on

the surface of the earth.

(2) There is a tremendous variation in the eating habits of

different animals.

(3) All fishes have short life span.

(4) Animals living in deserts and those in coastal areas are

same in their characters.

 (5) The needs of all living things are met because of diversity of

life forms.

(6) The predator may not be able to live in the absence of prey.

(7) Biodiversity in the plant kingdom is increased due to single

crop method of farming.

(8) Documentation of traditional knowledge is unnecessary.

(9) The Earth summit was held in Brazil.

Ans. (1) False. Thousands of species of plants and animals can

be seen to exist on the surface of the earth. (2) True. (3) False.

Some fishes have short life span while some have longer life span.

(4) False. Animals living in desert and those living in coastal areas

are different in their characters. (5) True. (6) True. (7) False

Biodiversity in the plant kingdom is reduced due to single crop

method of farming. (8) False. Documentation of traditional

knowledge is necessary. (9) True.

Q. 9 Fill in the blanks :

1. (1) Some fishes use their tail fin as a ……… to defend

themselves.

(2) Some fishes have short life span while some have………life

span.

(3) ……… is the important factor that brings about biological

diversity.

(4) ………and………breeds have replaced the local varieties of

cattle.

(5) Types of animals and their numbers have ……… due to

hunting.

Ans. (1) weapon (2) longer (3) Environment (4) Hybrid,

imported (5) dwindled.

2. (1) Efforts to protect knowledge related to ……… have already

begun.

(2) Gene banks for preserving the genes of local varieties have

become possible due to advances in the field of ……… .

(3) The ……… was held at Rio-de-Janeiro in Brazil.

(4) Various efforts are being made to conserve ……… species.

(5) Living things live in ……… environments.

Ans. (1) biodiversity (2) biotechnology (3) Earth summit

(4) endangered (5) diverse.

Q. 10 Choose the correct alternative and complete the

following statements :

(1) The great variety of living species which we see is referred

to as ………

(a) diversity (b) difference

(c) biodiversity (d) environment

(2) There is ……… variety seen in factors that transmit genes

from one generation to the other.

(a) no (b) little (c) tremendous (d) uniform

(3) Biodiversity is important for the ……… of living things.

(a) existence (b) decomposition (c) protection (d) growth

(4) The explosive rate at which the ……… of our country is

growing is the main reason for the decline in the

biodiversity.

(a) money (b) forests (c) population (d) blind faiths

(5) Land has been cleared by cutting away the ……… from it.

(a) vegetation (b) population

(c) water supply (d) buildings

(6) ……… in the environment is also a cause for the

disappearance of many species.

(a) Humidity (b) Pollution

(c) Diversity (d) Technology

(7) Compiling and documenting ……… knowledge is one of the

means for protecting biodiversity.

(a) foreign (b) traditional

(c) religious (d) technical

(8) Treaty at Earth summit emphasizes the need for nurturing

……… .

(a) biotechnology (b) biodiversity

(c) international trade (d) peace and harmony

(9) Class of animals called ……… includes fishes of all kinds.

(a) Mammalia (b) Reptilia (c) Pisces (d) Aves

(10) The traditional method of ……… farming is decreasing

gradually.

(a) multi crop (b) single crop (c) mechanized (d) tribal

Ans. (1) biodiversity (2) tremendous (3) existence

(4) population (5) vegetation (6) Pollution (7) traditional

(8) biodiversity (9) Pisces (10) multi crop.

Q. 11 Match the following :

(Type of feeding)	(Animals)
(1) Gnawing the fruit	(a) Hen
(2) Swallowing the prey	(b) Dog
(3) Picking up grains	(c) Squirrel
(4) Licking the food	(d) Snake
	(e) Fish

Ans. (1) Gnawing the fruit – Squirrel (2) Swallowing the

prey – Snake (3) Picking up grains –Hen (4) Licking the food – Dog.

[2]

(1) Rabbit	(a) Producer
(2) Tiger	(b) Decomposer
(3) Bacteria	(c) Predator
(4) Grass	(d) Herbivore
	(e) Omnivore

Ans. (1) Rabbit – Herbivore (2) Tiger – Predator (3) Bacteria –

Decomposer (4) Grass – Producer.

[3] ‘A’ ‘B’

(1) Nurturing animals	(a) Rio-de-Janeiro
(2) Protecting wildlife	(b) Gene banks
(3) Biotechnology	(c) Sanctuaries
(4) Biodiversity treaty	(d) Zoos
	(e) Playgrounds

Ans. (1) Nurturing animals – Zoos (2) Protecting wildlife –

Sanctuaries (3) Biotechnology– Gene banks (4) Biodiversity

treaty – Rio-de-Janeiro.