NCERT Class 8 Science Chapter 7 Solution
Brief Information: This post contains the solution for Chapter 7 Conservation of Plants and Animals of Class 8 of the CBSE and also Gujarat Board (GSEB) books by GCERT (based on new NCERT).
Q1. Fill in the blanks.
(a) A place where animals are protected in their natural habitat is called Wildlife sanctuary.
(b) Species found only in a particular area is known as endemic species.
(c) Migratory birds fly to faraway places because of climatic changes.
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
Q.3. Discuss the effects of deforestation on the following:
(a) Wild animals
Ans. Forests provided natural habitat to he wild animals. Loss of forest area can lead to endangerment of wild animals. They can even become extinct. Moreover, loss of habitat pushes wild animals towards human area like villages and cities. This increase the conflict between wild animals and humans.
(b) Environment
Ans. Forests maintain ecological balance. They absorbs carbon dioxide and other pollutants. Tree enables infiltration of water to ground and recharge ground water levels. Tree covers check soil erosion. Deforestation results in global warming (increased temperature), lowering of ground water, disturbance of water cycle, increase in natural calamities and soil erosion.
(c) Villages (Rural areas)
Ans. Decrease in soil fertility due to deforestation may affect the agricultural practice and life of those who gains livelihood from forest by collecting forest products and hunting.
(d) Cities (Urban areas)
Ans. In cities the pollution will rise due to decrease in tree which absorbs carbon dioxide. The temperature of cities will increase.
(e) Earth
Ans. The ecological balance will be disturbed. It will increase the temperature of entire planet and people will face increased number of natural calamities. Earth may become inhabitable on long time due to indiscriminate deforestation.
(f) The next generation
Ans. The next generation will face problems like reduced soil fertility and global warming. It will lead to scarcity of food and other resources. Next generation will be not able to see many flora and fauna due to their extinction.
Â
Q.4. What will happen if
1. We go on cutting trees.
Ans. If we go on cutting trees, then there will be problems like
a.) Increased carbon dioxide in air resulting in global warming.
b.) Lowering of ground water level.
c.) Disturbed water cycle and decrease in rainfall
d.) Soil erosion and desertification.
e.) Increase in the natural disasters.
2. The habitat of an animal is disturbed.
Ans. If the habitat of an animal is disturbed, then it may lead to issues like
a.) Animal becoming endangered and even extinct.
b.) Animals may enter human area and there may be rise in human-animal conflicts.
3. The top layer of soil is exposed
Ans. If the top layer of soil is exposed, then the chances of soil erosion (loss of top soil) will increase. Soil erosion will result in decrease of fertility of the land and on longer duration desertification may occur. Moreover, the water holding capacity of the soil will decrease. The movement of water from surface to ground will be reduced. This can cause flood like situation.
Q.5. Answer in brief.
1. Why should we conserve biodiversity?
Ans. Biodiversity refers to the variety in life existing on the earth, their inter-relationships, and their relationships with the environment. Biodiversity is essential to maintenance of ecological balance and ensure continuance of food chain.
Â
2. Protected forests are also not completely safe for wild animals. Why?
Ans. Protected forests are not completely safe for wild animals due to illegal poaching. The people living in neighbouring area of protected forests encroach and destroys them.
3. Some tribals depend on the jungle. How?
Ans. The tribals derive their basic needs from the jungle. They obtain wood for fuel and shelter from jungle and food by hunting small animals. They also collect leaf of few medicinal plants and make handicraft from bamboo found in forest to earn livelihood.
4. What are the causes and consequences of deforestation?
Ans. Deforestation occur due natural and man-made causes. Natural cause include forest fire and severe drought. The man-made cause include cutting of trees for purpose of
a.) Procuring land for cultivation.
b.) Building houses and factories.
c.) Making furniture or using wood as fuel
Indiscriminate deforestation leads to:
a.) Increase in the temperature and pollution level on the earth.
b.) Increase in the level of carbon dioxide in the atmosphere.
c.) Lowering of groundwater levels.
d.) Increase in frequency of natural calamities like floods and droughts.
e.) Deforestation results in more soil erosion. The fertility of soil reduce over time due to soil erosion. This leads to desertification of region.
f.) Extinction of flora and fauna.
5. What is Red Data Book?
Ans. Red Data Book is the source book which keeps a record of all endangered animals and plants. It is maintained by international organisation – IUCN.
6. What do you understand by the term migration?
Ans. Migration means the movement of a species from its own habitat to some other place during a certain period in a year for breeding or to overcome some climatic conditions.
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. Trees absorb carbon dioxide and other pollutants and provide pure environment. They are essential for providing shelter to wild animals and maintain ecological balance. Therefore, we should not cut trees indiscriminately to meet the demands for factories and shelter. Cutting of tree should be planned. If trees are cut than equivalent numbers of tree should be grown to compensate the loss.
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. We can contribute to maintenance of green wealth in our locality by taking steps such as
1. Afforestation – Planting tree saplings on barren land. Moreover, others should be prohibited from cutting down trees.
2. Preventing disposal of garbage and waste in forest area to maintain its pristine nature.
3. Promoting people to recycle and reuse waste.
4. Encouraging people to use natural resources prudently or economically.
5. Conserving water and other natural bodies.
Q.8. Explain how deforestation leads to reduced rainfall.
Ans. Trees absorb carbon dioxide from atmosphere for process of photosynthesis. Carbon dioxide is well known for its green house effect which leads to global warming. Deforestation means lesser tree are available for taking up carbon dioxide. Increased carbon dioxide in atmosphere results in increased temperature thus higher rate of evaporation and reduction of precipitation. This impact on water cycle cause drought. i.e low rainfall.
Q.9. Find out about national parks in your state. Identify and show their location on the outline map of India.
Q.10. Why should paper be saved? Prepare a list of ways by which you can save paper.
Ans. Paper are made from fully grown trees. Widespread deforestation has occurred for manufacturing of paper. It has lead to degradation of environment. Moreover, harmful chemical agents are use in making paper. So, it is essential to save paper to save forests.
Paper can be saved by:
1. Encouraging the recycle and reuse of paper.
2. Using using e-paper or electronic paper in which documentation is done is soft form on computer.
3. Prudent use of paper.
Q.11. Complete 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.
Ans.
Down
1. Species on the verge of extinction. – Endangered
2. A book carrying information about endangered species. – Red Data Book
5. Consequence of deforestation. – Deserts
Across
1. Species which have vanished. – Extinct
3. Species found only in a particular habitat. – Endemic
4. Variety of plants, animals and microorganisms found in an area. – Biodiversity