It is to be noted that the ecosystem has been classified in a variety of ways, but the following classification is based on habitat; terrestrial ecosystems and aquatic ecosystems.
Aquatic ecosystems may be sub-divided further, mainly on the basis of habitat i.e. freshwater or marine ecosystems, and ecosystems which are marginal between terrestrial and aquatic systems (i.e. estuaries and sea shores). Terrestrial's ecosystems have been classified using the life zone system, devised by Hold ridge.
The following classification of ecosystems by Odum 1975) is of special interest to geographers because it presents different ecosystems as entities in the context of energy flow, which is the most important attribute of all ecosystems.
Besides, this classification is a much more possibility than deterministic approach and has considerable application in the real world.