NIOS Class 10 Social Science Chapter 11 Bio – Diversity

NIOS Class 10 Social Science Chapter 11 Bio – Diversity Solutions to each chapter is provided in the list so that you can easily browse through different chapters NIOS Class 10 Social Science Chapter 11 Bio – Diversity and select need one. NIOS Class 10 Social Science Chapter 11 Bio – Diversity Question Answers Download PDF. NIOS Study Material of Class 10 Social Science Notes Paper 213.

NIOS Class 10 Social Science Chapter 11 Bio – Diversity

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Also, you can read the NIOS book online in these sections Solutions by Expert Teachers as per National Institute of Open Schooling (NIOS) Book guidelines. These solutions are part of NIOS All Subject Solutions. Here we have given NIOS Class 10 Social Science Chapter 11 Bio – Diversity, NIOS Secondary Course Social Science Solutions for All Chapters, You can practice these here.

Bio – Diversity

Chapter: 11




Q. 1. Biodiversity is fundamental to the existence of life on the earth. Justify the statement by giving any two reasons. 

Ans: Biodiversity is fundamental to the existence of life on the earth because this is extremely valuable in different phases of life which includes providing of food, water, fiber, fuel etc. and regulating of climate and diseases.

Q. 2. Explain hot spots in 30 words. 

Ans: A biodiversity hot spot is a region with a high level of endemic species. Endemic species are those species that are found in certain limited area.


Q. 1. Why are the tropical rain forests called evergreen forests ? Explain in 30 words.

Ans: Trees in these forests remain green all the year round as the climate of the region is warm and wet throughout the year. The leaves of the trees do not fall in any particular season. Hence, they are evergreen.

Q. 2. Give reasons:

(i) Tidal forests areas along the eastern coast experienced sever destruction during cyclones in recent years because:

Ans: Tidal forests along the eastern coast provide protection against cyclones. But in recent years due to massive deforestation of these forests these areas have been experiencing sever destruction during cyclones in recent years.

(ii) Himalayan forests have been economically more exploited in comparison to tropical evergreen forests because:

Ans: Tropical vegetation has a dense and mixed vegetation of all kinds and hence their. economic exploitation is not viable whereas species in Himalayan vegetation are less dense and exploited easily.


Q. 1. Fill in the blanks correctly from alternative provide in the bracket. 

(i) At present there are __________ wildlife

Sanctuaries. (441/551)

Ans: 551.

(ii) __________ in Assam is known for the Indian rhinoceros. (Manas/Kaziranga)

Ans: Kaziranga.

(iii) Harike wet land is located in __________ (Punjab/Himachal Pradesh)

Ans: Punjab. 

(iv) biosphere reserve is in the state of Tamil Nadu. (Gulf of Mannar/Pachmarhi) 

Ans: Gulf of Mannar.

Q. 2. Define Wet land.

Ans: A wet land is an area of land whose soil is saturated with moisture either permanently or seasonally. Such areas may also be covered partially or completely by shallow pools of water.

Q. 3. Make a list of any three efforts you can make to safeguard biodiversity of your surroundings.

Ans: Some of the efforts you can make to safeguard biodiversity of your surroundings are:

(i) Stop cutting trees 

(ii) Plant more trees

(iii) Protect all animals 

(iv) Establishment of hospitals for injured birds and animals. 

(v) Stop throwing garbage in rivers and polluting environment.


Q. 1. Define biodiversity. Explain the inter relationship between natural vegetation, organisms. wildlife and micro.

Ans: Biodiversity is a term to describe the variety of life on earth which includes different components of physical environment such as temperature, soil and water. In simple term biodiversity is the total number of genes, species and ecosystem of a region. 

It includes: (i) genetic diversity.

(ii) species diversity. and 

(iii) ecosystem diversity.

Q. 2. Describe in brief the character- istics and distribution of tropical evergreen forests in India.

Ans: Characteristics of Tropical evergreen forests:

1. These grow in an area of annual rainfall more than 200 cms. 

2. The trees in these forests shed their leaves at different times.

3. These are tall trees reaching the height of 60 mts. 

4. Large number of species both in plant and animal kingdom are found.

5. These are inaccessible hence commercially less useful.

These are found, on the slopes of Western Ghats, West Bengal, Orissa and north eastern states of India.

Q. 3. Give any two differences between the moist deciduous forest and dry deciduous forests.


Moist deciduous forestsDry deciduous forests
1. These are found in areas receiving annual rainfall between 100 cm. to 200 cm.1. These forests are found in areas receiving annual rainfall between 70 to 100 cms.
2. These are found in Jharkhand, Maharashtra, M.P., West Orissa, Chhattisgarh and on the eastern slopes of Western Ghats.2. These forests are found in dry regions of U.P., Bihar, Jharkhand, Orissa states and rainier parts of Deccan plateau.
3. Trees found in these forests are Teak, Sal, Shisham, Sandalwood, Khair and Bamboos.3. Trees found in these forests are Teak, Palash etc.

Q. 4. State three objectives for establish- ment of biosphere reserves in India. 

Ans: Objectives to establish the biosphere

reserves are:

1. To conserve diversity and integrity of plants and animals and microorganisms.

2. To promote eco-friendly sustainable life in the areas. 

3. To promote ecological conservation, research, education, awareness and training in the life of such areas.

Q. 5. What are the main causes of loss of biodiversity? State any four. 

Ans: The main causes of loss of bio- diversity are as under :

1. Increasing population

2. Changing lifestyle.

3. Commercial exploitation of the natural resources.

4. Industrialisation.

Q. 6. Justify the need for conservation of natural vegetation, wildlife and micro organisms with suitable reasons.

Ans: The need for conservation of natural vegetation, wildlife and micro- organisms is essential and it is the need of times because:

1. Biodiversity is fundamental to our existence on the earth.

2. We need food, water, shelter and fibre in nature. These are interrelated and inter- dependent. 

3. If any one of them is disrupted it would have multiple impact on other components of biodiversity.

Q. 7. Study the table given below and answer the following questions:

National Parks/ Wildlife SanctuaryProtected wildlife
1. Kaziranga1. Tiger
2. Manas2. Elephant
3. Periyar3. Musk deer
4. Corbett4. Lion
5. Dachigam5. Rhino
6. Wild Buffalo
7. Panther
8. Bear

(a) Match the name of the animal to the national park in which they are protected.

(b) Encircle the animals which are not protected in any national park.

(c) Write the names of the animal which is protected in more than one National Park.

Ans: (a) 

Name of AnimalNational Park/ Wildlife Sanctuary
TigerCorbett (Uttarakhand)
ElephantPeriyar (Kerala)
Musk deerDachigam (J&K)
LionGir (Gujarat)
RhinoKaziranga (Assam)
Wild buffaloKaziranga (Assam)
PantherCorbett (Uttarakhand)

(b) Bear Not in any park 

(c) Tiger, Elephant, Panther, Wild buffalo. 

Q. 8. Refer to the figure No. 11.3 

(a) Find out the type of vegetation in your state.

Ans: Tropical deciduous vegetation. 

(b) Which areas have thorn forests? 

Ans: Western areas of Rajasthan, parts of Haryana and Gujarat have the thorn forests. 

(c) Which areas have tidal forests and why are they restricted to those areas? 

Ans: Delta of Ganga and Brahmaputra has the tidal forests. Deltas of Krishna, Mahanadi, Godavari and Kaveri have also these forests. There forests are restricted to these areas because these are influenced by tides and wet land topography.



Q. 1. What type of monsoon forests are confined to slopes of Western Ghats?

Ans: Moist deciduous forest. 

Q. 2. Name two useful trees of the thorn and scrub forests.

Ans: Kikar, Babul, Khair and Date palm. 

Q. 3. Name two mangrove trees.

Ans: Sundari and Garjan.

Q. 4. Give one major characteristic of tidal forests. 

Ans: They can survive both in fresh and salt waters. 

Q. 5. Give the natural habitat of elephant.

Ans: Hot and wet forests in jungles of Assam and Kerala.

Q. 6. Give the type of natural habitat in which rhinoceros live.

Ans: Swampy and marshy lands of Assam and north West Bengal.

Q. 7. What is the total number of national parks and wildlife sanctuaries in India?

Ans: 75 National Parks and 551 Wildlife Sanctuaries. 

Q. 8. Name our national bird and animal.

Ans: Peacock and tiger.

Q. 9. Name two wildlife sanctuaries where elephants are found in large number.

Ans: Kaziranga and Gulf of Mannar.

Q. 10. Name a wildlife sanctuary in Rajasthan. 

Ans: Ranthambore.

Q. 11. What is endemic vegetation?

Ans: It is purely Indian vegetation.

Q. 12. What is exotic vegetation?

Ans: The vegetation came from the places outside India. 

Q. 13. Which factors are responsible for huge diversity in flora and fauna kingdom?

Ans: These are:


2. Sunlight.

3. Precipitation. 

4. Soil and relief.

Q. 14. What are biosphere reserves? Give example one from south and one from north.

Ans: It refers to protect and conserve bio- diversity of India. A biosphere reserve in north is at Uttarakhand state (the Valley of Flowers) and at Kerala state in south. The former is known as Nanda Devi biosphere reserve and the later is known as Nilgiri biosphere reserve.

Q. 15. What is a national park? 

Ans: It is a reserved area of preserving its natural vegetation, natural beauty and the wildlife e.g., Corbett National Park in Uttarakhand, Shivpuri National Park in Madhya Pradesh.


Q. 1. What are the tidal forests?

Ans: Tidal or littoral forests are found in tidal areas along the coast and river deltas. They can survive in both fresh and salt waters. They have mangrove trees, some of which are very dense and impenetrable, like Sundari, Gurjan yielding hard, strong and durable wood. They are mainly found in the deltas of Kaveri, Ganga, Brahmputra, Mahanadi, Godavari and Kaveri.

Q. 2. Why do tropical deciduous forests shed their leaves during summer?

Ans: Tropical deciduous forests shed their leaves in 6 to 8 weeks in the hot weather to avoid transpiration from their broad leaves.

Q. 3. Why are evergreen forests found in the western slopes of Western Ghats ? Give two reasons.

Ans: (i) They have uniform warm to high temperature throughout the year.

(ii) Rainfall in these areas is above 200 cm. with a very short dry season. Uniformly distributed rainfall almost throughout the year is another reason. That is why evergreen forests are confined to the western slopes of Western Ghats.

Q. 4. Why are thorn forests found in Rajasthan? Give two reasons.

Ans: Thorny forests are found in Rajasthan as they have long roots. Thorns and sharp spines help them to thrive well in very high temperature and arid conditions.

Q. 5. Write the measures you understand fit for the protection of wild life.

Ans: 1. Ban on the hunting is strictly imposed.

2. Poachers and herdsmen should not be allowed to enter the forests. 

3. More national parks and wildlife sanctuaries should be set up.

4. Captive breeding of wildlife should be encouraged.

5. Seminars, workshops, exhibitions are being arranged.

6. Adequate medical facilities are being provided.

7. Proper conditions should be created for living and breeding.

Q. 6. Distinguish between Extinct and Endangered species. 


Extinct SpeciesEndangered Species
1. These are plant and animal species disappeared and now no seen in the world. These are not sighted since last six decades.1. These species are those which are in danger of getting extinct.
2. About twenty species of plants are extinct.2. About 1300 spices of plants are endangered.
3. Revival of extinct species is not possible nor they can be preserved.3. Much can be done to save these species. Biosphere reserves have been set-up for this purpose.

Q. 7. Distinguish between Tropical deciduous forest and Temperate forests with grasslands.


Tropical Deciduous ForestsTemperate Forests with Grasslands
1. These are the most dispersed forests of India.1. These are confined to mountainous areas.
2. These are spread over a region receiving rainfall between 200 cms and 100 cms.2. These are spread over snowfall regions and high altitudes.
3. These are found in north-eastern states along the foothills of the Himalayas, Jharkhand, Orissa, Chhattisgarh and on the eastern slopes of the Western Ghats.3. These are grown in southern slopes of the Himalayas and places of high altitudes in southern and north-east India.
4. Trees of these forests shed their leavesfor about six to eight weeks in dry summer.4. Evergreen broad leaf trees are found here.
5. The trees found in these forests are: sal, teak, palash, arjun, mahua, peepal, sandalwood and bamboo.5. Here are grown apples, pears, cherries etc. fruit trees. Oaks, chestnuts, pine, cedar, silver fir are the other common trees.
6. The animals found in these forests are: lion, tiger, pig, deer, elephants.6. Kashmiri stag, spotted deer, wild sheep, jack, rabbit, yak, snow leopard, antelope are the common animals found here.

Q. 8. Distinguish between reforestation and afforestation.


1. It is practiced in areas where forests have been destroyed.1. New forests are planted in the new areas.
2. Two saplings are planted to replace every felled tree.2. One sapling is planted to get one tree.
3. It is practiced to avoid the evils of jhumming agriculture.3. It is practiced to bring more area under forests.

Q. 9. Give four characteristics of tidal forests.

Ans: Characteristics of Tidal Forests:

(i) These forests are found in the deltas.

(ii) The trees grown here are able to survive in both fresh and saline waters. 

(iii) Mangroves are the common varieties with roots of the plants submerged under water Eg., Sundari trees in Sunderbans.

(iv) Apart from Sundari trees, palm, coconut, keora, agar, screw pine and amor are also found in tidal forests. 

Q. 10. What are bio reserves? What are their uses?

Ans: A protected area reserved for the conservation of endangered species of flora and fauna in their natural habitat is called a biosphere.

Uses of Biosphere reserve:

1. Endangered species of animals and plants are protected. 

2. These rare plants and animals are transmitted to the future generation in all their natural glory.

3. The surrounding areas are reserved for research work for the betterment of flora and fauna.

Q. 11. What are migratory birds?

Ans: Some species of birds keep moving from one place to another across the countries. Eg., Siberian crane. Many of these birds arrive on wet lands in India specially during winters. They build their nests and breed here.

Q. 12. Write a brief note on the cage birds.

Ans: The birds domesticated or semi domesticated in India are called cage birds. Munia is a cage bird colorful and attractive to look at. It is a small seed eating bird only about 10 cm in length which readily breed in captivity given the right conditions. Likewise birds are good mimics and have a wide range of notes. Some other birds in this category are shama, parakeet, mynah etc. The Shama is a black and red bird with a long black and white tail. It sings a beautiful flute like song. Mynah is glossy black bird with its red bill and curious yellow wattle on the head. It has extra ordinary ability to mimic human speech.

Q. 13. Give the main causes for depletion of biodiversity in India. 

Ans: Main causes are as under:

1. With the increase of population there is increasing demand for forest products and several forests have been cleared for agriculture. 

2. Human beings influences and utilize the vegetation and wildlife. The greed of human brings to lead to over utilization of the forests.

3. Pollution due to chemical and industrial wastes, acid deposits etc. are responsible for the depletion of natural resources. 

Q. 14. Why is it necessary to increase the areas under forests? Give reasons.

Ans: It is necessary to increase the areas under forest because: 

1. Forests provide various products like timber, medicinal herbs etc. 

2. They are natural habitats of flora and fauna. They are necessary to maintain the ecological balance.

3. Forests help in rainfall, check floods and soil erosion.

Q. 15. What is a Biome? State the number of Biomes into which the land ecosystem is divided and also the basis for the grouping.

Ans: Biome is a very large ecosystem on land. It has distinct type of vegetation and animal life. Five principal biomes are found in the world. These are Forests, Savanna, Grasslands, Deserts and Tundra.

These biomes are useful for studying the world pattern of vegetation. The grouping of these biomes is done on the basis of plant for materials. Animals are also included. These groups are based on soils, water and heat.


Q. 1. Discuss the altitudinal zones of vegetation in the mountainous regions in India.

Ans: A succession of natural vegetation belts from tropical to Tundra region are found within an altitude of six km.

1. The foothills of the Himalayas have moist deciduous forest with sal as the most dominant tree beside bamboo grass.

2. They are followed by wet hill forests between 1000 to 2000 m above the sea level. Oak, chestnut, ash, birch and apple trees are common here. At the same height in north eastern hills where is rains heavily there are subtropical pine forests found with chir as dominant trees.

3. Between 1600 m to 3000 m above sea level, pine, cedar, silver fir and spruce are common coniferous trees, inner Himalayas and areas with less rainfall have deodar.

4. Temperate coniferous forests give way to alpine forests at 3600 m width. The species are silver fir, pine, birch and juniper.

5. They are filled by alpine grasslands, shrubs and scrubs slowly giving way to snow fields. 

Q. 2. Why is conservation of wildlife very essential? Explain. 

Ans: Conservation of Wildlife: Special efforts are being made to preserve endangered species of birds and animals. Periodic census is undertaken to find out the latest position and trends in this regard. The Project Tiger has been a great success. Now we have 25 tiger reserves in various parts of the country. Likewise, Rhino Project is being implemented in Assam. The Indian Bustard of Rajasthan and Malwa plateau are yet another endangered species. Even the number of lions had been dwindling for a long.

Steps have been taken for the protection and conservation of the great biological diversity of our land. Under this scheme, the first bio- reserve has been set-up in the Nilgiris. It consists of 5500 square km. area and is spread at the tri-junction of Karnataka, Tamil Nadu and Kerala states. There are thirteen such zones to be reserved into it. The country has 89 national parks, 490 wildlife sanctuaries, 35 zoological gardens covering 1,30,000 sq. kms. area. Conservation of wildlife is essential in order to protect the endangered species of birds and animals as also maintain the ecological balance. Government of India has so for set- up thirteen biosphere reserves.

Q. 3. Write short note on the importance of forests.

Ans: Forests are valuable resources of the country. Forests provide mankind with a number of products. Forests have greatly influenced human activities. Following are the direct and indirect advantages of forests:

1. Forests provide many things to meet our requirements like wild fruits, nuts etc. Many tribals are depend on these products.

2. Forests are source of timber for house building, furniture making and ship building etc.

3. Forest supply 40% of fuel of the world wood.

4. Soft wood supply raw materials for wood pulp, paper industries.

5. Many products like rubber, gum, tanning materials, cork, camphor, herbs etc. are gather from forests.

6. Forests provide plywood and fiber wood for packing. 

7. Forests help in rainfall by capturing moisture in the air.

8. Forests prevent soil erosion. 

9. Forests increase the fertility of soil, help agriculture and maintaining ecological balance.

10. Forests provide shelter to wild animals. 

11. They check the advance of deserts.

Q. 4. Discuss the steps taken by the government to conserve our biodiversity. 

Ans: The following steps have been taken by the government to conserve the bio- diversity:

1. 13 biosphere reserves have been set-up in the country. 

2. 89 National parks 490 wildlife sanctuaries and 35 zoological gardens have been set-up to take care of natural heritage.

3. Financial and technical assistance to many botanical gardens is given by the government since 1992. 

4. Project Tiger, Project Rhino and Project Great Indian Bustard are introduced to protect these species. 

5. Steps have been taken to create awareness among the people of benefits of flora and fauna of the country.

Q. 5. Describe any three character- istics of Thorn Forests. 

Ans: Characteristics:

(a) These forests are grown in areas which have less than 70 cm of rainfall.

(b) These consists of thorny trees and bushes.

(c) These are found in Kachchh parts of Saurashtra, Rajasthan, U.P., Punjab, Haryana and low rainfall regions of Maharashtra.

(d) Trees of babul, cacti, acacias, palms, thorny bushes grown in these forests. 

(e) Trees are scattered and have long roots penetrating deep into the soil to tap ground water.

(f) The leaves are thick and small to reduce evaporation.

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