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

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

Exercises

1. Fill in the blanks.
(a) A place where animals are protected in artificial habitat is called a ______.
(b) Species found only in a particular area are known as ______.
(c) Migratory birds fly to far away places because of ______ changes.

Solution

(a) Zoo
(b) Endemic species
(c) Climatic

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

Solution

Wildlife Sanctuary	Biosphere Reserve
A wildlife sanctuary protects only animals and does not permit capturing or killing of them.	Biosphere reserves are protected areas for the conservation of wildlife, plants, and animals.

Zoo	Wildlife Sanctuary
Zoos are places where animals are kept in special enclosures and cages for public viewing by keeping them protected.	A wildlife sanctuary protects animals and does not permit capturing or killing of them.

Endangered Species	Extinct Species
Endangered species are those whose numbers are rapidly declining and their habitats are rapidly changing.	Extinct species are those that no longer exist on Earth.

Flora	Fauna
All the plant species found in a particular habitat are referred to as fauna.	All the animal species found in a particular habitat are referred to a flora.

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

Solution

(a) Deforestation destroys the natural habitat of wild animals and thus, they can become endangered. With forests being cleared, animals lose their homes, food sources, and protection from predators. This can lead to a decrease in their population, which can eventually lead to extinction if the loss of habitat is not addressed.
(b) Due to deforestation, atmospheric oxygen levels decrease, rainfall falls, and soil fertility declines. Consequently, floods and droughts are more likely to occur.
(c) Rural areas are mostly used for agriculture. Deforestation affects soil properties, which in turn affects agriculture.
(d) Deforestation pollutes the environment further in cities, and thus, life in cities will not be healthy. It results in less trees to produce oxygen and absorb carbon dioxide, which is essential for maintaining healthy air quality in cities.
(e) Deforestation increases the earth’s temperature, causing global warming. Trees absorb carbon dioxide from the atmosphere and use it to produce oxygen. When forests are cleared, fewer trees are available to absorb the carbon dioxide, leading to an increase in the overall atmospheric concentration of the gas and contributing to global warming.
(f) Deforestation results in climatic changes that have a major effect on the next generation, resulting in the loss of prosperity for the next generation.

4. What will happen if
(a) we go on cutting trees?
(b) the habitat of an animal is disturbed?
(c) the top layer of soil is exposed?

Solution

(a) Natural calamities such as floods and droughts are more likely if we continue cutting trees continuously.
(b) Some species will become endangered if their habitat is disturbed, as they are deprived of adequate food and shelter. This can lead to a decrease in their population, and if nothing is done to protect the species, it could eventually lead to extinction.
(c) If the top layer of the soil is exposed, the soil will have less humus and will become less fertile. Gradually, the land will convert into desert. This is called desertification.

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 a Red Data Book?
(f) What do you understand by the term migration?

Solution

(a) Biodiversity helps maintain healthy ecosystems, which provide us with food, clean air and water, and other resources we depend on. When species become extinct or are threatened, it can disrupt the balance of an ecosystem.
(b) It is also not completely safe for wild animals in forests that have been designated as protected. People living in the neighbourhood encroach upon the forests and cause them harm.
(c) In tribal communities that live near jungles, plants provide many things such as food, shelter, firewood for kitchen fuel, herbs and medicines.
(d) Deforestation is caused by a range of human activities, including logging, urbanization, agricultural expansion and mining. Forest fire and drought are some natural causes of deforestation.
(e) The Red Data Book is a source that keeps the list of endangered species. It is released by ICUN (International Union for Conservation of Nature). It was first released in 1963.
(f) Animals migrate to faraway places in search of food and breeding during climatic changes. Birds are more famous as long distance migrants. During winter months, birds from Siberia migrate to India for a warm climate and food.

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.

Solution

For such projects, it is not justified to cut down trees. By cutting down trees, carbon dioxide levels rise in the atmosphere, which increases temperature, leading to global warming. As trees bring rain, their number decreases. Therefore, the decrease in trees results in decreasing rainfall. The cutting down of trees also results in changes in soil properties, such as nutrient content and texture.

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

Solution

For maintenance of green wealth in our locality, we should
(i) Grow more and more trees on both sides of the road.
(ii) Discourage the cutting of trees.
(iii) Convince other people to plant new trees.
(iv) Take out rallies to create awareness among people.
(v) Coordinate with local authorities for proper help.

8. Explain how deforestation leads to reduced rainfall?

Solution

The removal of trees or other vegetation from an area will increase the Earth’s temperature. The increased temperature disturbs the water cycle and reduces rainfall.

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

Solution

The following map of India shows some of the major national parks. You can select those in your native state and fill in the map accordingly.

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

Solution

When we waste paper, we destroy forests. As we use more and more paper, we cut down more and more trees. To reduce deforestation, we must learn to recycle used paper in an efficient and economical manner. By saving paper, we can save the forest. We can take following steps to save paper:
(i) Collect used paper and recycle it.
(i) Old envelopes can also be used for doing the rough work.
(i) Paper should be recycled to minimize the need of cutting trees.
(i) Schools should encourage online submission of reports and assignments so that paper can be saved.
(i) Don’t take a printout unless it is absolutely necessary.

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.