question_answer

How is the rate of decomposition of detritus affected by its chemical composition, temperature and availability of oxygen?

Or

Discuss the condition of an ecosystem in the following situations.

(i) If producers drastically decrease in number.

(ii) If all organisms of one trophic level are eliminated or killed.

(iii) If top carnivores population is removed.

Answer:

Rate of decomposition of detritus can be affected in the following ways

· Availability of oxygen The rate of decomposition decreases in the anaerobic conditions, i.e. in the absence of oxygen, It increases in aerobic conditions because \[{{O}_{2}}\] is essential for the activity of decomposer organisms.

· Chemical composition of detritus Detritus rich in lignin, cellulose and chitin has slower rate of decomposition while, a detritus rich in nitrogen and water soluble substances such as sugar has a higher rate of decomposition.

· Temperature It acts as the most important factor among all. The rate of decomposition is high in warm and moist environment, while low temperature inhibits decomposition.

Or

(i) If the producers of an ecosystem drastically decrease in number due to any circumstance, the whole pyramid of energy would get affected because producers make the base of the pyramid.

There will be more competition among the consumers for food and other resources.

Subsequently, the consumers will have to move to a new area to fulfil their needs.

(ii) If all the organisms of a trophic level are killed, the number of individuals in the next trophic level will decrease due to unavailability of the food. As a result, the number of individuals of the lower trophic level will increase because no one will be present to feed upon them. This will cause an imbalance in the ecosystem.

(iii) In such a condition, where all the top carnivores or predators have been removed, the ecosystem will become imbalanced, A behavioural change will also occur in the prey species.