Definition of the ecosystem.

Meaning of Ecosystem:

The populations of organisms interact with each other in biological communities, and no biotic community can live in isolation. It lives in an environment which supplies its material and energy requirements and provides other living conditions. A biological community interacting with the non-living environment is called an ecosystem. An ecosystem can be natural or artificial, temporary or permanent.

A pond, a lake, a tract of forest, a coral reef, a large grassland, a village, an aquarium, a field of sugarcane, a manned spaceship, or a laboratory culture can all be regarded as ecosystems. Thus, an ecosystem may be defined as a dynamic system which includes both organisms (biotic component) and abiotic environment influencing the properties of each other and both necessary for the maintenance of life.

The concept of ecosystem was first put forth by Sir Arthur Tansley in 1935. Ecosystems can be recognised as self-regulating and self-sustaining units of landscape. Ecosystem is the major ecological unit.

In nature, two major categories of ecosystems may be distinguished:

(i) Terrestrial, and

(ii) Aquatic.

Forests, grasslands and deserts are main examples of terrestrial ecosystems, while ponds, lakes, streams or salt water (marine estuaries) represent aquatic ecosystems.

Ecosystem has both structure and function. The structure is related to species diversity. The more complex is the structure the greater is the diversity of the species in the ecosystem. The function of ecosystem is related to flow of energy and cycling of materials through structural components of the ecosystem.

According to E.P. Odum, the ecosystem is the basic fundamental unit of organisms and their environmental interacting with each other and with their own components. All the ecosystems of the earth are connected to one another, e.g., river ecosystem is connected with the ecosystem of oceans, and a small ecosystem of dead logs is a part of large ecosystem of a forest.

However, human activities may modify natural ecosystems into man -made or anthropogenic ecosystems. For example, natural forests have been cut and the land converted to tree plantations or agricultural systems. Sometimes dam construction involves submergence of forests and conversion to water reservoirs.