NCERT Solutions for Class-8 Science Chapter-7 Conservation of Plants and Animals

NCERT TEXTBOOK EXERCISES

Question 1. Fill in the blanks:
1. A place where animals are protected in their natural habitat is called………….
2. Species found only in a particular area is known as…………
3. Migratory birds fly to faraway places because of…………… changes.
Answer:
1. wildlife sanctuary
2. endemic species
3. climatic.

Question 2. Differentiate between the following:
1. Wildlife sanctuary and biosphere reserve
2. Zoo and wildlife sanctuary
3. Endangered and extinct specie
4. Flora and fauna
Answer:
1. Wildlife Sanctuary: The area that is reserved in a forest for the protection and preservation of wild animals. It also provides suitable living conditions.
    Biosphere Reserve: The area that is meant for the conservation of biodiversity. It also helps to maintain the culture of that area. One biosphere reserve may also contain other protected areas in it.
2. Zoo: A place where animals are protected in an artificial habitat.
    Wildlife Sanctuary: The area, that is reserved in a forest for the protection and preservation of wild animals.
3. Endangered Species: The animal species whose numbers are diminishing to a level that they might face extinction.
    Extinct Species: The animal species, whose numbers are nil (zero), because of changes in their habitat and other calamities.
4. Flora: The plants that are found in a particular area are called flora. For example, Sal, teak, jamun etc.
    Fauna: The animals that are found in a particular area are called fauna. For example, Chinkara, cheeta, leopard etc.

Question 3. Discuss the effects of deforestation on the following:
1. Wild animals
2. Environment
3. Villages (Rural areas)
4. Cities (Urban areas)
5. Earth
6. The next generation
Answer:
1. They won’t get their natural habitat and surroundings, as well as food. So either they will extinct or reach the verge of extinction or they will migrate to another forest. In course of their migration, they might be killed by humans.
2. Climatic changes disturb the environment. Global warming is caused due to accumulation of carbon dioxide. Because of deforestation and an increase in the temperature on earth, the water cycle will get disturbed and the reduced rainfall will cause droughts.
3. Villagers cannot grow food (crops) because of no rain as drought situations will prevail. Many poor villagers may die for want of food. The villagers will move to towns and cities. On one hand, villages will be completely deserted and on the other hand, the towns and cities will be overcrowded.
4. Cities flooded with drought-affected villagers will disturb the environment. Food-grains will either not available or if available, they will be costlier. People will also not get wood for making furniture and buildings.
5. Deforestation is a major cause, which leads to change in soil properties. Gradually the land will get converted into a desert. On the other hand, the snow of the mountains will melt due to global warming, and many coastal cities will be flooded causing disaster.
6. The next generation will either be extinct or if at all it exists, it will suffer from diseases and face life scarcity of food in life. So, the next generation will be ill, weak, and, consequently, face extinction.

Question 4. What will happen if:
1. we go on cutting trees.
2. the habitat of an animal is disturbed.
3. the top layer of soil is exposed.
Answer.
1. If we go on cutting trees, then:
    (a) The survival of mankind will become a threat, because of the low oxygen concentration in the atmosphere.
    (b) We have to face high temperatures and increased pollution levels.
    (c) Natural calamities will disrupt our life.
    (d) The water cycle will be disturbed.
    (e) If the habitat of an animal is disturbed, then:
    (f) The animals will lose their natural habitat and ultimately will be at the periphery to become endangered.
    (g) The survival of animal will be difficult, because of the drought and the rise in temperature.
2. If the top layer of soil is exposed, then:
    (a) The exposed top layer loses all its nutrients, especially the hummus.
    (b) It leads to a decrease in the water holding capacity of the soil.
    (c) The vegetation will go off from the field, and desertification will be the result.

Question 5. Answer in brief.
1. Why should we conserve biodiversity?
2. Protected forests are also not completely safe for wild animals. Why?
3. Some tribals depend on the jungle. How?
4. What are the causes and consequences of deforestation?
5. What is Red Data Book?
6. What do you understand by the term migration?
Answer:
1. Biodiversity refers to the variety in life existing on Earth, their interrelationships, and their relationship with the environment, so we should conserve as the food chain should not get disturbed, otherwise the whole ecosystem will be affected.
2. Protected forests are also not completely safe for wild animals, because poaching or capturing of the animal takes place in these areas. Wild animals are killed by poachers.
3. Tribes, usually the residents of the jungle, are dependent on the jungle for the fulfillment of their daily needs of life.
4. The causes and consequences of deforestation are:
    (a) It increases the temperature and pollution level on earth.
    (b) It decreases the level of oxygen in the atmosphere and groundwater level is also lowered.
    (c) The rainfall and the fertility of the soil will decrease.
    (d) The chances of natural calamities are more because of deforestation.
    (e) It changes the soil properties.
    (f) It affects the top layer of the soil, which exposes the lower hard and rocky layers.
5. The Red Data Book is the only source as a book, which keeps a record of all the endangered animals and plants.
6. The term migration means the phenomenon of movement of a species from its own habitat to some other habitat for a particular time period every year for some specific purposes like breeding or to overcome unfavourable conditions.

Question 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.
Answer: Of course, to meet the ever-increasing demand in factories and for shelter, trees are being continually cut, which is hot justified at all. If one tree is cut, at least five trees should be grown so that the reforestation process may remain continuous.
But, if trees are cut blindly and no trees are planted then the earth may face global warming, no rainfall, climatic change, soil erosion, and desertification, etc. So, cutting trees for any reason at all is not justified.

Question 7. How can you contribute to the maintenance of the green wealth of your locality? Make a list of actions to be taken by you.
Answer: For the contribution to maintain of green wealth in my locality, the different actions to be taken are;
1. not to allow anybody to cut any trees;
2. always try to plant saplings in the residing area;
3. never ever show the neglection to water the plants;
4. always trimming the plants from time to time for their better growth.

Question 8. Explain how deforestation leads to reduced rainfall.
Answer: Deforestation leads to the accumulation of CO2 in the atmosphere which results in global warming as CO2 traps the heat of the sunrays. The increase in temperature on earth will disturb the water cycle and reduce rainfall, causing drought in the region.

Question 9. Find out about national parks in your state. Identify and show their location on the outline map of India.
Answer: Do yourself.

Question 10. Why should the paper be saved? Prepare a list of ways by which you can save paper.
Answer: Manufacturing paper needs trees. By cutting trees, deforestation is caused which disturbs the balance in nature. If the paper is saved or recycled, many trees can be saved. Paper can be saved by recycling. Paper can be recycled.5-7 times and can be used. If everyone who uses paper, could save at least one sheet of paper in a day, we can save many trees in a year.
We should save and reuse the used paper and recycle it. By following these steps we can save not only the trees but also the energy and water needed for manufacturing paper.

Question 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.
Answer: