The struggle between organisms to survive as they attempt to use the same limited resources in the same place at the same time.

An interaction in which one organism kills another for food or nutrients.

Any relationship in which two species live closely together and that benefits at least one of the species.

A type of symbiosis between two species in which one species benefits and the other species is neither helped nor harmed.

A type of symbiosis in which both species benefit from living together.

A type of symbiosis in which one organism lives with, on, or in a host and harms it.

The series of predictable changes that occur in a community over time.

The first species to populate an area during succession.

The number and variety of different species in an area.

A species that influences the survival of many other species in an ecosystem.

The disappearance of all members of a species from Earth.

Species that are not native to a habitat and can out-compete native species in an ecosystem.

The benefits that humans derive from ecosystems.

The study of how organisms interact with each other and their environment.

Anything naturally occurring in the environment that humans use.

When nothing is lost or gained; to remain constant.

The ability of an ecosystem to maintain bioviersity and production indefinitely.

The practice of helping a degraded or destroyed ecosystem recover from damage.