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Ecosystems
An ecosystem is a place that consists of a community of organisms, the physical
(abiotic) factors that influence it and all interactions between organisms.

Ecosystems are dynamic with energy flowing from the sun through autotrophs to
heterotrophs and decomposers. Elements such as carbon, nitrogen, sulphur and
phosphorous are continually…

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transferred from the grazing to the decomposer food chain in the form of faeces and, after
death, animal tissue.

Much of the energy that enters the organisms at one trophic level is used by those
organisms and is, therefore, not available to the next trophic level; energy is lost during…

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Energy consumed by tertiary consumers
Ecological Efficiency =
Energy consumed by secondary consumers ×100%


Arable farmers and growers attempt to make net primary productivity as high as possible.
Livestock farmers do the same for secondary productivity.

Method Crop Plants Livestock
(Producers) (Primary Consumers)
Maximise Energy Input Optimum planting distances Provide…

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When ground becomes available for colonisation for the first time a process of primary
succession begins in which the community changes over time. The sequence of
communities that develops is known as a sere. Plants and animals in different seral
communities show adaptations to survive. Earlier stages in succession are…

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Digest proteins in detritus into amino Oxidises ammonium ions to nitrite ions to
acids provide energy
Deaminate amino acids to form Oxidises nitrite ions to nitrate ions to
ammonium ions provide energy
Nitrate ions released are available for
plants to absorb



There is a large quantity of nitrogen in the…

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After reaching a certain size, the trunks of some mature trees are cut down to a stump.
Fresh shoots then grow out of these stumps and can be harvested. Rotational coppicing
allows wood to be harvested without loss of biodiversity and also helps young shoots as
light is then allowed…

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