The regions of the surface, atmosphere, and hydrosphere of the earth (or analogous parts of other planets) occupied by living organisms.

Are the living components of an ecosystem.

Are non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems

Is all the organisms of the same group or species, which live in a particular geographical area, and have the capability of interbreeding.

An interacting group of various species in a common location.

A biological community of interacting organisms and their physical environment.

A large naturally occurring community of flora and fauna occupying a major habitat, e.g. forest or tundra.

The natural home or environment of an animal, plant, or other organism.

Is the evolutionary result of a species morphological, physiological, and behavioral adaptations to its surroundings.

The preying of one animal on others.

Interaction between two different organisms living in close physical association, typically to the advantage of both.

The doctrine that mutual dependence is necessary to social well-being.

An association between two organisms in which one benefits and the other derives neither benefit nor harm.

Is a relationship between species, where one organism, the parasite, lives on or in another organism, the host, causing it some harm, and is adapted structurally to this way of life.

An organism that is able to form nutritional organic substances from simple inorganic substances such as carbon dioxide.

An organism deriving its nutritional requirements from complex organic substances.

An animal that feeds on plants.

An animal that feeds on flesh.

An animal or person that eats food of both plant and animal origin.

An animal which feeds on dead organic material, especially plant detritus.

An organism, especially a soil bacterium, fungus, or invertebrate, that decomposes organic material.

Each of several hierarchical levels in an ecosystem, comprising organisms that share the same function in the food chain and the same nutritional relationship to the primary sources of energy.