What is an ecosystem ? List its two main components. We do not clean natural ponds or lakes but an aquarium needs to be cleaned regularly. Why is it so ? Explain.

Explanation

Ecosystem is the structural and functional unit of biosphere, comprising of all the interacting organisms in an area together with the non-living constituents of the environment.
Two main components of Ecosystem are :
(i) Biotic component
(ii) Abiotic component
An aquarium is an artificial and incomplete ecosystem compared to pond or lakes which are natural, self-sustaining and complete ecosystem where there is a perfect recycling of materials.
Aquarium need to be cleaned regularly because of :
(i) absence of natural decomposer.
(ii) stagnancy of water.