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NCERT Solutions of Science for Class 8 Lesson-7 CONSERVATION OF PLANTS AND ANIMALS.

TEXTUAL QUESTIONS

Q.1- Fill in the blanks –

(a) A place where animals are protected in their natural habitat is called _____.

(b) Species found only in a particular area is known as ______.

(c) Migratory birds fly to far away places because of ______ changes.

Ans- (a) sanctuary

(b) endemic species

(c) climate

Q.2- Differentiate between the following –

(a) Wildlife sanctuary and biosphere reserve.

(b) Zoo and wildlife sanctuary.

(c) Endangered and extinct species.

(d) Flora and fauna.

Ans- (a) (i) Wildlife Sanctuary – The area where animals are protected from any disturbance to them and their habitat is called wildlife sanctuary.

(ii) Biosphere Reserve – The large areas of protected land for conservation of wildlife, plant and animal resources and traditional life of the tribals living in the area are called biosphere reserve.

(b) (i) Zoo – The small area where animals are protected for the entertainment of people which is called a zoo.

(ii) Wildlife Sanctuary – The area where animals are protected from any disturbance to them and their habitat is called wildlife sanctuary.

(c) (i) Endangered Species – Animals whose numbers are diminishing to a level that they might face extinction are called endangered species.

(ii) Extinct Species – The species which were found on the earth in the past and they have extincted from earth now are called extinct species.

(d) (i) Flora – The plants found in particular area are called flora.

(ii) Fauna – The animals found in particular area are called fauna.

Q.3- Discuss the effect of deforestation on the following –

(a) Wild animals

(b) Environment

(c) Villages (rural areas)

(d) Cities (urban areas)

(e) Earth

(f) The next generation

Ans- (a) Effect of deforestation on wild animals – Deforestation destroys the natural habitat of wild animals which threatens the existence of animals and may lead to their extinction.

(b) Effect of deforestation on Environment – Deforestation disturbs the natural balance of environment. It increases the temperature and pollution level on earth. It increases the level of carbon dioxide and decreases the level of oxygen in the atmosphere, which give rise to global warming. It also increases the chances of natural calamities like floods and droughts.

(c) Effect of deforestation on villages (rural areas) – Most of the village population depends on agriculture. Deforestation may disturbs the water cycle, which may reduce rainfall and could cause droughts. Also trees prevent soil erosion. Fewer trees result in more soil erosion which affect the fertility of the soil and also the crop yield. Gradually the fertile land gets converted into deserts and affects the village life.

(d) Effect of deforestation on cities ( urban life) – Cities or urban areas are not directly affected by deforestation but the production of industries established in urban areas could decrease due to the non-availability of raw material. Deforestation results in global warming which could increase the level of pollution in the cities.

(e) Effect of deforestation on Earth – Deforestation leads to global warming. The increased temperature on the earth disturbs water cycle which could result in the natural calamities like droughts, floods and desertification.

(f) Effect of deforestation on the next generation – Deforestation may affect the life of the next generation drastically. The next generation will not be able to see the most of the animal species because of the loss of habitat. The next generation will not get clean environment to live in.

Q.4- What will happen if :

(a) We go on cutting trees

(b) The habitat of animal is disturbed.

(c) The top layer of soil is exposed.

Ans- (a) If we go on cutting trees then –

(i) the water cycle will get disturbed which may result in natural calamities like droughts, floods and desertification.

(ii) the temperature and pollution level on earth will increase.

(iii) the environment balance will be disturbed.

(iv) most of the animal species could lost their habitat.

(v) the raw materials that we get from trees like wood, fruits, medicines, wood pulp, rubber etc will not be available.

(b) If the habitat of an animal is disturbed then –

(i) the animals will loose their natural habitat.

(ii) most of the animals will reach at the level of extinction.

(c) If the top layer of the soil is exposed then –

(i) the fertility of the soil will decrease and gradually it will convert into a desert.

(ii) the production of the crops will decrease.

(iii) the water holding capacity of the soil will decrease.

Q.5- Answer in brief –

(a) Why should we conserve biodiversity?

(b) Protected forests are also not completely safe for wild animals. Why?

(c) Some tribals depend on the jungle. How?

(d) What are the causes and consequences of deforestation?

(e) What is red data book?

(f) What do you understand by the term migration?

Ans- (a) The conservation of biodiversity is compulsory for saving animals from extinction.

(b) Protected forests are also not completely safe for wild animals because smugglers and illegal poachers cause harm to animals by hunting them for personal gain.

(c) Some tribals live in jungles. The most of the requirements of their life like food, clothes, shelter and living are fulfilled from the jungles.

(d) Causes of deforestation –

(i) Procuring land for cultivation.

(ii) Building houses and factories.

(iii) Making furniture and using wood as fuel.

Consequences of deforestation –

(i) Leads to global warming.

(ii) Increase in temperature and pollution level on earth.

(iii) Disturbs water cycle. This could cause natural calamities like droughts, floods and desertification.

(iv) Change in physical properties of soil.

(iv) Decreases the ground water level.

(v) Extinction of animals and plants species.

(e) Red Data Book – It is a source book which keeps a record of all the endangered animals and plants. Red data book is maintained internationally by an organisation.

(f) Migration- It is the phenomenon of the movement of animals especially birds from their own habitat to some other habitat due to climatic changes.

Q.6- In order to meet the ever-increasing demand in factories and for shelter, trees are being continually cut. Is it justified to cut trees for such projects? Discuss and prepare a brief report.

Ans- It is not justified that trees are being continually cut in order to meet the ever-increasing demand in factories and for shelter. Land is needed for establishing factories and residence and it is made available by cutting forests. But at the same time, we must remember that we are losing the benefits of forests while meeting this demand. The balance of the environment is disturbed. The shelter of wildlife is destroyed. Deforestation leads to natural calamities which affects the lives of all living beings.

Q.7- How can you contribute to the maintenance of green wealth of your locality? Make a list of actions to be taken by you.

Ans- For the maintenance of green wealth of our locality, we can contribute in the following ways –

(i) Plant more and more trees with the help of local social organisations particularly NCC, NSS, Eco clubs etc.

(ii) Start reforestation programs by making small groups at local level.

(iii) Organise seminars to understand the importance of plants and trees.

(iv) Inspire your friends and relatives that they should celebrate their birthdays or special occasions by planting a tree.

(v) Aware the people in your locality about global warming and motivate them to plant more and more trees.

Q.8- Explain how deforestation leads to reduced rainfall.

Ans- Forests are helpful in maintaining water cycle in nature. Trees give out huge amount of water in the form of water vapours through the transpiration process. In the absence of trees, there will be no water vapours and the clouds will not be formed. Hence it will lead to reduced rainfall.

Q.9- Find out about National Parks in your state. Identify and show their location on the outline map of India.

Ans-

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National Parks in different States of India

Q.10- Why should paper be saved? Prepare a list of ways by which you can save paper.

Ans- Paper is manufactured from the wood pulp. A large numbers of trees can be saved by saving papers.

The ways by which we can save the papers are-

(i) Use the paper wisely.

(iii) Recycling the paper.

(iii) Use slate for rough work.

(iv) Use jute or cloth bag instead of paper bags.

Q.11- Compete the word puzzle.

Down

(1) Species on the verge of extinction.

(2) A book carrying information about endangered species.

(5) Consequence of deforestation.

Across

(1) Species which have vanished.

(3) Species found only in a particular habitat.

(4) Variety of plants, animals and microorganisms found in an area.

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Ans-

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Chapter At A Glance

  • Wildlife sanctuary, National park and biosphere reserve are names given to the areas meant for conservation and preservation of forest and wild animals.
  • Biodiversity refers to a variety of living organisms in a specific area.
  • Plants and animals of particular area are called flora and fauna of that area.
  • Endemic species are found only in a particular area.
  • Endangered species are those which are facing danger of extinction.
  • Red data book contains a record of all endangered species.
  • Migration is the phenomenon of movement of a species from its own habitat to some other habitat for a particular time period every year for a specific purpose like breeding.
  • We should save, reuse and recycle paper to save trees, water and energy.
  • Reforestation is the restocking of destroyed forests by planting new trees.