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

1. Fill in the blanks.

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

Answer: sanctuary

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

Answer: endemic

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

Answer: climatic

2. Differentiate between the following.

(a) Wildlife sanctuary and biosphere reserve

Answer:

Wildlife Sanctuary	Biosphere Reserve
Area in which animals are protected from hunting and other possible dangers	Large area is constructed for conservation of plants and animals
It provide proper living conditions and protection to wild animals	It provides conservation for animals, plants and microorganisms
For example – Pachmarhi sanctuary	For example – Pachmarhi biosphere reserve

(b) Zoo and wildlife sanctuary

Answer:

Zoo	Sanctuary
Zoo is an artificial environment constructed to keep animals for public exhibition	Sanctuaries area in which animals are protected from hunting and other dangers
It is an artificial habitat	It is natural habitat
Animals may or may not adapt with environmental conditions at zoo	No problems of adaptations as animals are in their own natural habitat
For example – National zoological park , New Delhi	For example – Pachmarhi Sanctuary

(c) Endangered and extinct species

Answer:

Endangered species	Extinct species
Species that are on verge of extinction are called endangered species	Species that no longer exist are called extinct species
Blue whale is one of the endangered species	Dodo is one of the extinct species

(d) Flora and fauna

Answer:

Flora	Fauna
All plants living in particular area is called flora	All animal living in particular area is called fauna
Sal, mango, etc are flora of Pachmarhi biosphere	Wild dog, Leopard, etc are fauna of Pachmarhi biosphere

3. Discuss the effects of deforestation on the following.

(a) Wild animals

Answer: Deforestation involve cutting of forests or vegetation for development of industries or agricultural area, etc. Forests are the habitat of animals, thus, cutting of forests destroys habitat of these animals, which causes decrease in their numbers.

(b) Environment

Answer: Plants take atmospheric carbon dioxide and releases oxygen in environment. If forests are cut, concentration of carbon dioxide will increase in atmosphere, this will increase temperature of earth causing global warming.

(c) Villages (Rural areas)

Answer: Roots of plants hold soil particles firmly. If forests or other vegetation are cut down then top layer of soil gets removed due to wind, rain or other natural phenomena. Thus, deforestation increases soil erosion. This causes decrease in humus and soil becomes less fertile.

(d) Cities (Urban areas)

Answer: Deforestation causes increase in level of carbon dioxide in atmosphere, which causes global warming. It also, causes calamities like floods and droughts.

(e) Earth

Answer: Deforestation causes soil erosion, floods, drought, etc. Increase in level of carbon dioxide causes global warming which melts glaciers. It disturbs the habitat of animals and can lead to extinction of several species. Moreover, it disturbs water cycle.

(f) The next generation

Answer: Deforestation is changing environmental condition in various ways. It causes floods, droughts, global warming, soil erosion, etc. If this continuous, then our next generation will face severe environmental problems.

4. What will happen if.

(a) we go on cutting trees.

Answer: f we go on cutting trees, natural habitat of animals will get destroyed. It will also cause soil erosion and decrease in fertility of soil. It causes global warming, which increases temperature of the earth, this also disturbs water cycle. This may lead to situations of floods and droughts. It promotes desertification and can also result in other natural calamities.

(b) the habitat of an animal is disturbed.

Answer: Habitat of animals provides food, shelter and protection for animals. If habitat of animals get disturbed then animals will go to some other places in search of food and shelter. Therefore, it will result in killing of animals by other animals. If animals move to city area then they can harm humans also.

(c) the top layer of soil is exposed.

Answer: If top layer of soil is exposed then it also exposes bottom layer of the soil. This layer contains less humus and soil is less fertile. If soil erosion takes place continuously then this will result into infertile land.

5. Answer in brief.

(a) Why should we conserve biodiversity?

Answer: Plants animals and microorganisms in that area is called as biodiversity. Plants and animals are interdependent on each other for survival. If life of any of one is destructed, this will affect on other. Thus, there is need to conserve biodiversity to maintain nature’s balance.

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

Answer: Protected forests are not completely safe for wild animals because people who live near forests use forest resources to fulfill their requirements. This may lead to killing of animals and cutting of plants, which are sold to get money.

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

Answer: Tribal depend on forest for their basic needs like food, fodder branches of trees, etc.

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

Answer:

• Causes of deforestation –
  • Forests are cut down for development of industries and construction of buildings
  • Forests are cut down for agricultural purpose and cattle grazing
  • Forest are cut down to get firewood for fuel
• Consequences of deforestation –
  • Results in soil erosion
  • Loss of biodiversity and disturbance in water cycle
  • Floods and droughts
  • Global warming

(e) What is Red Data Book?

Answer: Red data book maintains list of all endangered species of plants and animals. This book is maintained by international union for conservation of nature and natural resources.

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

Answer: Migration is movement of organisms from one place to another at particular period of time in every year. Migration mainly takes place due to in-adaptable climatic conditions or environment for breeding.

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: No. It is not justified to cut trees for projects like factories and shelter. Trees are major source of oxygen. They take in atmospheric carbon dioxide and release oxygen in atmosphere. If trees are cut down concentration of carbon dioxide increases in atmosphere. Roots of trees holds soil firmly. Cutting of trees increases soil erosion. Moreover, it increases possibility of floods or droughts. Forests increases biodiversity and fertility of soil.

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

Answer: Actions taken by me are as follows

• Spread awareness about tree plantation and its benefits
• Plant more and more trees
• Water plants daily
• Arrange group activities for tree plantation
• Encourage people to take care of existing trees

8. Explain how deforestation leads to reduced rainfall.

Answer: Trees take in carbon dioxide from the atmosphere and gives out oxygen. If trees are cut down level of concentration of carbon dioxide will increase in atmosphere. This will increase the temperature of earth thereby, causing global warming. Increase in temperature disturbs the water cycle, thus, it will change pattern of rainfall. This causes reduced rainfall, leading to drought conditions.

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

Answer:

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

Answer: Seventeen fully grown trees are used to make one tonne of paper. By saving paper, we will be saving trees, thereby saving our environment and maintaining the balance of nature. Following are ways through which you can save paper-

• Recycle waste paper
• Use paper wisely
• Use both sides of paper for writing
• Switch to electronic services, thereby replacing the need of paper
• Reuse paper

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:

• Down : 1) Endangered 2) Red data book 5) Drought
• Across: 1) Extinct 3) Endemic 4) Biodiversity

Check other lessons NCERT Solutions for Class 8

Download free NCERT textbook class 8 Science – Chapter 7 Conservation of Plants and Animals