EXERCISES
Q1. Which of the following groups contain only biodegradable items?
a. Grass, flowers, and leather
b. Grass, wood, and plastic
c. Fruit peels, cake, and lime juice
d. Cake, wood, and grass
Ans:-
a)Grass, flowers and leather
c) Fruit peels, cake, and lime juice
d) Cake, wood and grass
Above all are the groups that contain only biodegradable items. Since plastic is not a biodegradable substance, that group cannot be considered as a biodegradable.
Q2. Which of the following constitute a food-chain?
a. Grass, wheat, and mango
b. Grass, goat, and human
c. Goat, cow, and elephant
d. Grass, fish, and goat
Ans:-
b. Grass, goat, and human
Here, goat is the producer, goat is the primary consumer and human is the secondary consumer.
Q3. Which of the following are environment-friendly particles?
a. Carrying cloth bags to put purchases in while shopping
b. Switching off unnecessary lights and fans
c. Walking to school instead of getting your mother to drop you on her scooter
d. All of the above
Ans:- d) All of the above
Q4. 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 food supply to the next level will strop resulting in an imbalance of the ecosystem. As a result animals in the higher levels will die making the growth of animals in the lower trophic levels increase in an enormous way. All of this will affect the overall balance in the ecosystem.
Q5. Will the impact of removing all the organisms in the trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?
Ans:- Yes, the impact of removing all the organisms in a trophic level will be different for different trophic levels. For example, if all the producers are removed, there is a chance of death or migration of the primary consumers which will upset the trophic levels. This is the same for all the levels. Therefore, the removal of organisms at any level would upset the whole ecosystem as the food chain is disturbed. The survival of the higher level animals is completely dependent on the animals at the lower levels.
Q6. What is the biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?
Ans:- Biological magnification can be defined as the progressive increase in the concentration of non-biodegradable wastes in the food chain. As there is an increase in the magnification at the primary level of the ecosystems, all the other levels do get affected and the concentration may vary when compared to first level.
Q7. What are the problems caused by the non-biodegradable wastes that we generate?
Ans :-Following are the problems caused by the non-biodegradable wastes:
i. These substances cannot be decomposed by the microorganisms.
ii. As the quantity increases, dumping becomes a problem.
iii. Non-biodegradable wastes like heavy metals may enter the food chain in the upper trophic levels.
iv. They may escape to the ground water which causes soil infertility and disturbance in pH of the soil.
Q8. If all the waste we generate is biodegradable, will this have no impact on the environment?
Ans :-
Biodegradable wastes are decomposed by the microorganisms into simpler substances which can be used by the producers as a raw material. But following are the effects of too much of biodegradable wastes:
i. As the decomposition of the biodegradable wastes are slow, they produce awful smell and when inhaled by humans it can be harmful.
ii. The dumping areas can be a place where harmful organisms may start to breed which can be harmful to humans as well as plants and animals.
iii. Increase in the number of aquatic organisms may result in depletion of oxygen.
Q9. Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?
Ans :- Ozone layer is a protective cover for the earth. It prevents harmful UV rays from entering the earth as these rays harmful and can result in skin cancer. But the air pollutants like chlorofluorocarbons (CFCs) are the main reason for the depletion of the ozone layer. Too much of UV rays are harmful for plants as they affect the photosynthesis, destroy planktons and decomposers. These are the reasons why damage of ozone layer a cause of concern.
