Editing Ecosystem (section)

{{Short description|Community of living organisms together with the nonliving components of their environment}}
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{{Redirect|Biosystem|the journal|BioSystems{{!}}''BioSystems''}}
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| alt1 = [[Coral reef]]s are a highly [[Productivity (ecology)|productive]] [[marine ecosystem]].
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| footer = Left: [[Coral reef]] ecosystems are highly [[Productivity (ecology)|productive]] marine systems.<ref>{{cite journal|last=Hatcher|first=Bruce Gordon|year=1990|title=Coral reef primary productivity. A hierarchy of pattern and process|journal=Trends in Ecology and Evolution|volume=5|issue=5|pages=149–155|doi=10.1016/0169-5347(90)90221-X|pmid=21232343|bibcode=1990TEcoE...5..149H }}</ref> Right: [[Temperate rainforest]], a [[terrestrial ecosystem]].
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{{TopicTOC-Biology}}

An '''ecosystem''' (or '''ecological system''') is a system formed by [[Organism|organisms]] in interaction with their [[Biophysical environment|environment]].<ref name="Chapin-2011m" />{{rp|458}} The [[Biotic material|biotic]] and [[abiotic component]]s are linked together through [[nutrient cycle]]s and [[energy]] flows.

Ecosystems are controlled by external and internal [[Environmental factor|factors]]. External factors—including [[climate]] and what [[parent material]]s form the soil and [[topography]]—control the overall structure of an ecosystem, but are not themselves influenced by it. By contrast, internal factors both control and are controlled by ecosystem processes. include [[decomposition]], the types of species present, root competition, shading, disturbance, and succession. While external factors generally determine which [[Resource (biology)|resource]] inputs an ecosystem has, the availability of said resources within the ecosystem is controlled by internal factors.

Ecosystems are [[wikt:dynamic|dynamic]] entities—they are subject to periodic disturbances and are always in the process of recovering from some past disturbance. The tendency of an ecosystem to remain close to its equilibrium state, is termed its [[resistance (ecology)|resistance]]. The capacity of a system to absorb disturbance and reorganize while undergoing change so as to retain essentially the same function, structure, identity, and feedbacks is termed its [[ecological resilience]]. 

Ecosystems can be studied through a variety of approaches—theoretical studies, studies monitoring specific ecosystems over long periods of time, those that look at differences between ecosystems to elucidate how they work and direct manipulative experimentation. [[Biome]]s are general classes or categories of ecosystems. However, there is no clear distinction between biomes and ecosystems. [[Ecological classification|Ecosystem classifications]] are specific kinds of ecological classifications that consider all four elements of the definition of [[ecosystems]]: a biotic component, an [[abiotic]] complex, the interactions between and within them, and the physical space they occupy. Biotic factors of the ecosystem are living things; such as plants, animals, and bacteria, while abiotic are non-living components; such as water, soil and atmosphere.

Plants allow energy to enter the system through [[photosynthesis]], building up plant tissue. Animals play an important role in the movement of [[matter]] and energy through the system, by feeding on plants and on one another. They also influence the quantity of plant and [[Microbe|microbial]] [[Biomass (ecology)|biomass]] present. By breaking down dead [[organic matter]], [[decomposer]]s release [[carbon]] back to the atmosphere and facilitate [[nutrient cycling]] by converting nutrients stored in dead biomass back to a form that can be readily used by plants and microbes.

Ecosystems provide a variety of goods and services upon which people depend, and may be part of. Ecosystem goods include the "tangible, material products" of ecosystem processes such as water, food, fuel, construction material, and [[medicinal plant]]s. [[Ecosystem services]], on the other hand, are generally "improvements in the condition or location of things of value". These include things like the maintenance of [[Water cycle|hydrological cycles]], cleaning air and water, the maintenance of oxygen in the atmosphere, crop [[pollination]] and even things like beauty, inspiration and opportunities for research. Many ecosystems become degraded through human impacts, such as [[Erosion|soil loss]], [[Air pollution|air]] and [[water pollution]], [[habitat fragmentation]], [[Interbasin transfer|water diversion]], [[Wildfire suppression|fire suppression]], and [[introduced species]] and [[invasive species]]. These threats can lead to abrupt transformation of the ecosystem or to gradual disruption of biotic processes and degradation of [[Abiotic component|abiotic]] conditions of the ecosystem. Once the original ecosystem has lost its defining features, it is considered [[Ecosystem collapse|"collapsed]]". [[Restoration ecology|Ecosystem restoration]] can contribute to achieving the [[Sustainable Development Goals]].

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