Question

(a) Name two biodegradable and two non-biodegradable wastes.
(b) Name the biotic and abiotic components of ecosystem.
(c) What is the role of decomposers in the ecosystem?
(d) If the plants get 10000 J of energy from the sun, how much energy will be available to tiger in the following food chain?
Plants → Deer → Tiger
​(e) A harmful chemical enters food chain comprising peacock, frog, grass, snake and grasshopper. Which of these organisms will have the maximum concentration of harmful chemical in its body? Why?

Answer 1

(a) Biodegradable wastes - Paper, vegetable wastes
Non-biodegradable wastes - Plastic, glass objects

(b) Biotic components - Plants and animals
Abiotic components - Land and air

(c) Decomposers include microorganisms such as bacteria and fungi that obtain nutrients by breaking down the remains of dead plants and animals.

Role of decomposers -

• They help in the breakdown of organic matter or biomass of dead plants and animals into simple inorganic raw materials such as CO₂, H₂O and nutrients.
• They help in the natural replenishment of soil.
• They help in keeping the environment clean.

(d) The energy is transferred according to the 10% law of energy transfer.
In this case, plants get 10000 J of energy.
Deer will get 10% of this energy i.e. 1000 J.
The amount of energy tiger will get is = $\frac{10}{100}\times 1000=100\mathrm{J}$

(e) The increase in the concentration of pollutants or harmful chemicals with the increase in trophic level is called biomagnification.

The food chain formed by these organisms would be -
Grass→Grasshopper→Frog→Snake→Peacock

In this case, the peacock occupies the last trophic level which means the maximum concentration of harmful chemicals will be present in its body.