An ecosystem is an ecological system, the interactions of plants, animals and other organisms with non-biological environmental factors in a certain areas.
History and specifics[]
Rainforests, grasslands and deserts are examples of specific types of ecosystems which feature animals and plants specifically adapted to live within the environmental constrains of the system.
The Armada was a series of agricultral domes which maintained an ecosystem, introducing birds and insects to regulate infestation rather than using artificial pesticides. (TNG comic: "Space Seeds")