CHAPTER 1 (COMPONENTS OF ENVIRONMENT)

CHAPTER  1 (SECTION D & E)

D. Answer the following questions in brief.

1. Name the major components of the environment.

Answer: Physical environment and biological environment are the major components of the environment.

2. What is meant by Sima and Sial?

Answer: The uppermost part of the lithosphere is composed of rocks rich in silica and aluminium called sial. Below the sial layer, the rocks are mainly rich in silica and magnesium and are called sima.

3. Mention the distribution of water in the Northern and Southern hemispheres.

Answer: The distribution of water is not uniform in both the Northern and the Southern Hemispheres. It is estimated that 43 % of the total area covered by water lies in the Northern Hemisphere whereas the remaining 53 % lies in the Southern Hemisphere.

4. Give the literal meaning of four spheres of environment.

Answer:

(1) Atmosphere – ‘the sphere of air’
(2) Lithosphere – ‘the sphere of rocks’
(3) Hydrosphere – ‘the sphere of water’
(4) Biosphere – ‘the sphere of life’.

5. What is the atmosphere composed of?

Answer: The atmosphere is composed of a mixture of gases like oxygen, nitrogen, Carbon dioxide, hydrogen, etc, which forms an envelope around the earth.

E. Answer the following questions.

1. Differentiate between the physical and the biological environment.

Answer: The Physical environment includes all non-living things like land, water and air. While, The Biological environment includes all living things, such as plants and animals.

2. Why is the earth called the ‘Blue Planet’?

Answer: The Earth is called the Blue Planet because of abundance of water on its surface. The water bodies that include rivers, lakes, seas and oceans cover 71 per cent of the earth’s surface.

3. Define biosphere. Why is it important for us?

Answer: The word ‘biosphere’ literally means the ‘sphere of life’. Biosphere is the narrow zone of contact between all the three spheres of environment where all kinds of life exist. Therefore, it is important for us.

4. Explain with the help of an example how physical and biological components of the environment are interdependent.

Answer: The physical and the biological components of the environment are interdependent and cannot be separated. Any major change in the physical environment is bound to bring a change in the accompanying biological environment. For example, the development of soil takes years together and cannot be visualised through our senses. On the other hand, some changes are very sudden, like the changes brought about by the occurrence of an earthquake or volcano, etc.

5. Explain two ways in which human beings are disturbing the natural environment.

Answer: The two ways in which human beings are disturbing the natural environment are:

o    Forests are being cutting on a large scale which disturbs the environment.

o    The pollution is being increasing day by day.