Ecosystem

In general terms, an ecosystem can be defined as an ecological unit consisting of a community of organisms (an assemblage of plant, animal and other living organisms in an area —also referred to as a biotic community or biocoenosis) together with its abiotic (non-living)environment (such as soil, precipitation, sunlight, temperature, slope of the land, etc.). The word ecosystem is an abbreviation of the term, ecological system. A river, a swamp, a meadow, and a cave are all examples of ecosystems.

Some consider the ecosystem to be the basic unit in ecology. They may be very large, such as a tropic rain forest (some define a biome as an extensive ecosystem) or very small, such as a test tube of phytoplankton or an aquarium tank with plants and fish.

Unification aspect?

Early conceptions of this unit were as a structured functional unit in equilibrium. This equilibrium was characterized by energy and matter flows between its constituent elements. Others considered this vision limited, and preferred to understand an ecosystem in terms of cybernetics. From this view an ecological system is not a structured functional unit in equilibrium, but a functional organisation at dynamic equilibrium, or what was also called steady state. This branch of ecology that gave rise to this view has become known as Systems Ecology. Steady state is understood as the phase of an ecological systems evolution when the organisms are "balanced" with each other and their environment. This balance is achieved through various types of symbiosis, such as predation, parasitism, mutualism, commensalism, competition, and amensalism. Introduction of new elements, whether abiotic or biotic, into an ecosystem tend to have a disruptive effect. In some cases, this can lead to ecological collapse and the death of many native species. The abstract notion of ecological health attempts to measure the robustness and recovery capacity for an ecosystem. That is, how far the ecosystem is away from steady state.

Size, scale and boundaries

The size and scale of an ecosystem can vary widely. It may be a whole forest, as well as a small pond, or even the geobiosphere itself. Different ecosystems are often separated by geographical barriers, like deserts, mountains or oceans, or are isolated otherwise, like lakes or rivers. As these borders are never rigid, ecosystems tend to blend into each other. As a result, the whole earth can be seen as a single ecosystem, or a lake can be divided into several ecosystems, depending on the scale used.

History

The term ecosystem first appeared in a 1935 publication by the British ecologist Arthur Tansley (Tansley, 1935). However, the term had been coined already in 1930 by Tansley's colleague Roy Clapham, who was asked if he could think of a suitable word to denote the physical and biological components of an environment considered in relation to each other as a unit. Tansley expanded on the term in his later work, adding the ecotope concept to define the spatial context of ecosystems (Tansley, 1939). Modern usage of the term derives from the work of Raymond Lindeman in his classic study of a Minnesota lake (Lindeman, 1942). Lindeman's central concepts were that of functional organisation and ecological energy efficiency ratios. This approach is connected to ecological energetics and might also be thought of as environmental rationalism. It was subsequently applied by H.T.Odum, sometimes called the 'father' of ecosystems ecology, in founding the transdiscipline known as Systems Ecology.

Inter-species biological interactions in ecology

Amensalism • Commensalism • Mutualism • Neutralism • Synnecrosis • Predation (Carnivory, Herbivory, Parasitism, Parasitoidism, Cheating) • Symbiosis • Competition

See also

• Pond ecosystem
• Aquatic ecosystem
• Biogeochemical cycle
• Biome
• Biosphere
• Biosphere 2
• Corporate Ecosystem
• Ecological yield
• Ecosystem ecology
• Ecotope
• Ecotourism
• Edge effect
• Eugene Odum
• Food chain
• Hypolith
• Invasive species
• Landscape ecology
• Media ecosystem
• Overfishing
• Trophic level
• Systems Ecology

External links

• Teaching about Ecosystems
• Millennium Ecosystem Assessment (2005)
• A popularized version of the Millennium Ecosystem Assessment by GreenFacts.
• Bering Sea Climate and Ecosystem - current status
• Arctic Ecosystems and Climate: A Near Realtime Arctic Change website

References

ISBN links support NWE through referral fees

• Lindeman, R. L. 1942. The trophic-dynamic aspect of ecology. Ecology 23: 399-418.
• Tansley, A. G. 1935. The use and abuse of vegetational concepts and terms. Ecology 16: 284-307.

• Tansley, A.G. 1939. The British Islands and their Vegetation. Volume 1 of 2. University Press, Cambridge, Cambridge, United Kingdom. 484 pg.

Credits

New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:

• Ecosystem  ^history

The history of this article since it was imported to New World Encyclopedia:

• History of "Ecosystem"

Note: Some restrictions may apply to use of individual images which are separately licensed.