Chapter 13 Solutions — Earth as a System: Energy, Matter, and Life

Revise, Reflect, Refine

1. 1.
   Choose the most appropriate option to describe the role of biogeochemical cycles in an ecosystem.

   • (i) To provide food directly to all organisms.
   • (ii) To recycle essential nutrients between biotic and abiotic components.
   • (iii) To create new elements for use by living things.
   • (iv) To remove pollutants and toxins from the organism.
2. 2.
   Which of the following is primarily responsible for warming of the Earth?

   • (i) Solar radiation is immediately absorbed by carbon dioxide, which then releases it as heat.
   • (ii) The atmosphere's tiny particles absorb incoming solar radiation, which directly heats the Earth.
   • (iii) The Earth's surface absorbs solar radiation, which is then re-radiated and trapped by greenhouse gases.
   • (iv) The Earth's…
3. 3.
   Explain how climate change affects the water cycle. Illustrate with examples.
4. 4.
   Describe how albedo affects the Earth's surface temperature and its climate.
5. 5.
   How are mountain and valley breezes formed? Suppose there are two mountains, one covered with grass and another covered with barren rocks; would the temperature of the two mountain breezes be different? If so, how?
6. 6.
   You have witnessed weather phenomena, such as winds, storms, rainfall, etc. Which atmospheric layer is mainly responsible for such phenomena and what is the primary reason for its occurrence?
7. 7.
   Explain the processes involved in the nitrogen cycle. How would life on Earth be affected if nitrogen were not cycled?
8. 8.
   What are the impacts of deforestation on the Earth's oxygen and carbon cycles? What are the other consequences of deforestation?
9. 9.
   Explain with suitable diagram the path that carbon takes to go back to the atmosphere. You may start from plants using CO₂ from the atmosphere.
10. 10.
    Why is an excess of CO₂ in the atmosphere considered undesirable even though it is required by plants?
11. 11.
    How is heat lost from the surface of the Earth? What is its significance?
12. 12.
    If the Earth were a flat disc instead of a sphere, how would the patterns of solar radiation and temperature be different?
13. 13.
    Suppose there is a rise in atmospheric temperature on Earth. How would this affect the cryosphere, hydrosphere and biosphere?
14. 14.
    Explain how the Earth's atmosphere helps in maintaining a suitable temperature for life to survive on the Earth.
15. 15.
    Describe the interrelationship between different spheres of the Earth. Illustrate with example how these spheres function in a delicate balance.