Page "Ecosystem" Paragraph 4

Ecosystems are controlled both by external and internal factors.

External factors such as climate, the parent material which forms the soil and topography, control the overall structure an ecosystem and the way things work within it, but are not themselves influenced by the ecosystem.

Other external factors include time and potential biota.

Ecosystems are dynamic entities — invariably, they are subject to periodic disturbances and are in the process of recovering from some past disturbance.

Ecosystems in similar environments that are located in different parts of the world can end up doing things very differently simply because they have different pools of species present.

The introduction of non-native species can cause substantial shifts in ecosystem function.

Internal factors not only control ecosystem processes but are also controlled by them and are often subject to feedback loops.

While the resource inputs are generally controlled by external processes like climate and parent material, the availability of these resources within the ecosystem is controlled by internal factors like decomposition, root competition or shading.

Other internal factors include disturbance, succession and the types of species present.

Although humans exist and operate within ecosystems, their cumulative effects are large enough to influence external factors like climate.