Ecology is the study of the interactions between living things and the environment around them, including but not limited to other living things.
Ecology includes many sub-disciplines including theoretical ecology, applied ecology, behavioral ecology, systems ecology, ecosystems ecology, community ecology, population ecology, landscape ecology, conservation ecology, soil ecology, paleoecology, microbial ecology and agroecology.
Ecology also plays important roles in the inter-disciplinary fields of ecological economics, ecological health and ecological design.
An interesting, but controversial, idea in ecology studies is the Gaia theory.
See also: Environmentalism