Due to overpopulation, human habitation and number of industries have increased. For this reason, the areas of traditional cultivable land and natural forests have decreased. Sound, smoke, industrial waste, garbage and bad smell of the factories etc. are polluting the environment. As a result, the balance of environment is being disrupted.
The different animals of the world are not only dependable on one another, they are also dependable upon the physical factors of the environment e.g. soil, water, air and plants. For this reason, living beings cannot be separated from the nonliving. There is an intimate relationship between the living community and the non-living environment for survival. The interrelationship between organisms and their environment is ecology.
We understand from the discussion above that ecosystem has two components. One is the biotic community and the other is the non-living environment. It is the non-living environment, which holds the biotic community. In any particular environment of a geographical region, the relationships and interactions between living and nonliving objects are collectively known as Eco-system.