Ecosystems [ecosystems: communities of animals, plants and micro-organisms, together with the habitats where they live ] can be small-scale, covering a small area (such as a pond) or large-scale covering a large area (such as a tropical rainforest).

The world is divided up into ten major ecosystems. These large-scale ecosystems are called biomesbiomes: Large-scale ecosystems that can be categorised into one of nine major types. The type of biome is defined mainly by its climate..