Ecosystem: Definition and Types

 Ecosystem: Definition-

No organism or a species lives alone; always there are associates influencing each other and organizing themselves into communities. The organisms of any community besides interacting among themselves always have functional relationship with the external world or the environment. This structural and functional system of communities and their environment is called an ecological system or the ecosystem. The term ecosystem was first proposed by A.G. Tansley (1935). Schulze et al. (2004) defined ‘’ecosystem are thus networks of interactions between organisms and their environment in defined space.’’ The size of an ecosystem is very flexible depending upon the nature of habitat and purpose of study.

Types of ecosystem-

The kind of organism which can live in a particular ecosystem depends upon their physical and metabolic adaptations to the environment of that place of ecosystem and on certain aspects of the history of our planet, which has determined what organisms have been able to travel where. On earth, there are sets of ecosystems within a geographical region which are exposed to same climatic conditions and having dominant species with a similar life cycle, climatic adaptations and physical structure. In the biosphere, there are natural and artificial ecosystems.

1.   Natural ecosystem-

Natural ecosystems operate by themselves under natural conditions without any interference by man. Natural ecosystems carry out many public service functions for us. Waste water from houses and industries is often convertable to drinkable water by filtration through natural ecosystems, such as soil. Air pollutants from industries and automobiles are often trap on leaves or converted to harmless compound by forests. On the basis of particular type of habitat, they are further sub-divided as

a)     Terrestrial ecosystem-

They are often classified by the vegetation type that dominates the community. The types of vegetation affect the climate and soil structure and that characterize the particular ecosystem. Terrestrial vegetation has a rapid exchange of oxygen, water and carbon dioxide. The carbon dioxide concentration is affected by terrestrial vegetation seasonally and annually. Terrestrial ecosystem includes grassland ecosystem, crop ecosystem, forest ecosystem and desert ecosystem.

b)    Aquatic ecosystem-

They fall into two categories, freshwater and marine. Freshwater ecosystems are usually named upon the size and nature of freshwater body. It may be lotic (running water) such as river ecosystem, stream or lentic (standing water) such as Lake Ecosystem, pond ecosystem, whereas marine ecosystems include deep sea and oceans. The largest and most uniform aquatic ecosystem is marine ecosystem.

2.   Artificial ecosystem-

They are maintained artificially by man. A pond constructed as a part of a waste water treatment plant is an example of artificial ecosystem, the management can vary over a wide range of actions. Agriculture can be thought of as partial management of certain kind of ecosystem. Here, natural balance is distributed regularly by addition of energy and panned manipulation. For e.g. wheat maize and rice- fields etc, where man tries to control the biotic community as well as the physiochemical environment. The smallest artificial ecosystem that has been non to sustain a life over long period of time is ‘Folsom bottles’. These materially closed ecosystems were created by Professor Claire Folsom of university of Hawaii by placing water, algae, bacteria and sediment from Honolulu bay in a liter flask and sealing the top. The sealed bottles were placed near the window so that some energy is utilized by the biotic components during day time. Some of these have sustained life for nearly twenty years.

Types of ecosystem based on energy resources-

1.   Unsubsidized natural solar powered ecosystem-

In this type of ecosystems, the only source of energy is solar energy. For e.g. oceans, upland forest, grassland forest etc. These are unsubsidized in the sense that there is no auxiliary source of energy available to supplement solar radiation/ energy.

2.     Naturally subsidized solar powered ecosystem-

In these types of ecosystems the main source of energy is sun, which is originated by natural non solar energy. As a result of which extra amount of energy is available to the system that can be used for the production of more organic matter that may be exported to other systems or stored in themselves. The auxiliary natural source of energy may be tides, waves and currents, wind etc.

3.     Man subsidized solar power ecosystem-

In this type of ecosystem auxiliary fuels or other energy like man and machine labour, is supplied by man. The main source of energy is sun. Examples of these types of ecosystems are agriculture and aquaculture. The energy input by man may be in the form of fertilizers, animal power, machine power, sprays etc.

4.     Fuel powered ecosystems-

In these ecosystems, the sun energy is replaced by highly concentrated potential energy of fuel, chemical or nuclear fuel. Examples of these systems are cities, industrial park etc. These systems are man’s wealth generating and also pollution generating systems. In this system there is no limit of energy input.