List of top Science Questions on Ecosystem

We do not clean natural ponds or lakes, whereas an aquarium or a swimming pool needs to be cleaned regularly. Why?

Assertion (A): Food web is a network of several food chains operating in an ecosystem.
Reason (R): Food web decreases the stability of an ecosystem.

Consider the following food chain: Grass → Grasshopper → Frog → Snake → Eagle If the amount of energy available at third trophic level is 50 kJ, the available energy at the producer level was:

Differentiate between food chain and food web. In a food chain consisting of deer, grass and tiger, if the population of deer decreases, what will happen to the population of organisms belonging to the first and third trophic levels?

Which one of the following is not a natural ecosystem?

A food chain will be more advantageous in terms of energy if it has

two statements are given — one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (A), (B), (C) and (D) as given below.
Assertion (A): Greater numbers of individuals are present in lower trophic levels of all food chains.
Reason (R): As the amount of energy decreases at each successive trophic level, larger numbers of individuals are required at the lower trophic levels to support higher/next trophic levels.