concept of ecosystem

An ecosystem can be notice as a functional unit of

nature, where living organisms interact among themselves

and also with the surrounding physical environment.

Ecosystem varies greatly in size from a small pond to a

large forest or a sea. Many ecologists regard the entire

biosphere as a global ecosystem, as a composite of all

local ecosystems on Earth. Since this system is too much

big and complex to be studied at one time, it is convenient

to divide it into two basic categories, namely the

terrestrial and the aquatic. Forest, grassland and desert

are some examples of terrestrial ecosystems; pond, lake,

wetland, river and estuary are some examples of aquatic

ecosystems. Crop fields and an aquarium may also be

considered as man-made ecosystems.