MATHPAL CLASSES & SACHDEVA STUDY ZONE&
CATALYST INSTITUTE
CLASS 10
OUR ENVIRONMENT
Question1. Define environment?
Ans. The biotic and abiotic factors which surrounds any living organism is considered as its environment. It can be generally defined as a community of organisms living in a particular environment and the physical elements in that environment with which they interact.
Question2. What is a food chain?
Ans. The process of eating autotrophs by herbivores and herbivores being eaten by other animals is considered as food chain.
Question3. What will happen if we kill all the organisms in one trophic level?
Ans. If we kill all the organisms in one trophic level, the number of individuals in the next trophic level will decrease due to non-availability of food. Also, the number of individuals in the previous trophic levels will increase because there is no one to feed on them. This will cause imbalance in the environment.
Question4. If all the wastes we generate is biodegradable, will this have no impact on the environment?
Ans. It will have only short term impact on environment, the action of decomposers will slow down and some air/water pollution will be caused. However, in longer term, there will be no impact of biodegradable wastes on the environment.
Question5. What limits the number of trophic levels in a food chain.
Ans. There is a loss of energy as we go from one trophic level to the next, this limits the number of trophic levels in a food chain.
Question6. What is the harm of clay cups?
Ans. Clay cups cause depletion of top fertile soil as they are formed from the same.
Question7. Write the harmful effect of ozone depletion.
Ans. i. Cause the skin cancer
ii. Damage to eyes
iii. Immune system
Question8. Give the correct sequence of various & trophic levels in a food chain.
Ans.
Question9. Aquarium requires regular cleaning whereas lakes normally do not. Why?
Ans. Normally a lake has more diverse forms of life and hence a larger number of food chains. This leads to natural cleaning. Thus, the ecosystem is more stable. The aquarium has a very limited number of food chains and unable to sustain itself. Bu, sometimes there is excessive growth of algae in lake. Then it also needs to be cleaned.
Question10. How will accumulation of bio degradable waste effect our environment?
Ans. Accumulation of bio degradable waste will:
(a) not let minerals return to mineral pool
(b) become site of pest breeding
Question11. What is the role of decomposers in the ecosystem?
Ans. They decompose dead remains of plants and animals and their wastes organic products into simple inorganic substances which are released into the atmosphere for reuse by the plants. Thus, they help in recycling of materials.
Question12. Give reason: “Life on earth depends on the sun.”
Ans. Sun is the ultimate source of energy on earth. Only plants can convert solar energy into chemical energy (food), which is transferred to different organisms at various trophic levels. Energy stored in fossil fuel is also transferred solar energy because they made up of decomposed plants and animals. Hence, solar energy is utilized and transformed in different form which is utilized by us.
Question13. What are the harmful effects of acid rain?
Ans. (1) Acid rain makes the soil acidic which affects the growth of trees and cereal crops badly.
(2) It makes the water of lakes, ponds, etc acidic which affects the growth of aquatic plants and animals.
(3) Bacteria useful for maintaining soil fertility are killed.
(4) It affects the historical monuments and building badly specially those made up of marble.
Question14. What is 10% law? Give an example
Ans. According to 10% law only 10% of energy is available at the next trophic level. For example- If energy available at producer level is 1000J then at next level only 10% of 1000J i.e. 100J is available.
Question15. Why are green plants called producers ?
Ans. Green plants are also called producers because only they can synthesise organic food from inorganic raw materials with the help of solar energy in the process of photosynthesis. This food is not only used by green plants but also all other organisms called consumers.
