Ecosystem is a self-sustained and self-regulated segment of nature or landscape where living organisms interact and exchange materials amongst themselves and with their physical environment. The term was coined by Arthur Tansle.Ecosystem can be large or small, temporary or permanent, natural or anthropogenic, terrestrial or aquatic, complete or incomplete.
Ecosystem has a number of abiotic (nonliving)and biotic (living) components, all of which are interrelated and interact with one another. There is a regular inflow of energy from outside which is trapped by plants along with inorganic nutrient to form food. This is the primary productivity of an ecosystem. The food along with its contained energy passes to other biotic components. There is dissipation of energy at every step of transfer and functioning of biological systems. It is lost to environment. Inorganic nutrients are not lost. They are released for recycling when organic matter and inorganic wastes undergo decomposition. Because of regular inflow of energy and its dissipation with a regular input and output of nutrients, an ecosystem is called open system.
On the basis of nutritional requirements biotic components of an ecosystem are divided into three groups-producers, consumers and decomposers.
Producers in an ecosystem are the green plants because they have got the capacity to prepare their food using solar energy by photosynthesis.
Consumers are those organisms that consume the synthesized food or producers. The consumers depend on producers directly or indirectly.
Decomposers are the saprophytic microorganisms which obtain nourishment from organic remains.