A community of organisms and their abiotic, or nonliving, environment.

The study of the interactions of living organisms with one another and with their environment.

An environmental factor that is not associated with the activities of living organisms.

An environmental factor that is associated with or results from the activities of living organisms.

A group of organisms of the same species that live in a specific geographical area.

All of the populations of species that live in the same habitat and interact with each other.

An organism that can make its own food by using energy from its surroundings.

An organism that gets energy by breaking down the remains of dead organisms or animal wastes and consuming or absorbing the nutrients.

An organism that eats other organisms or organic matter.

An organism that kills and eats all or part of another organism.

An organism that is killed and eaten by another organism.

A diagram that shows the feeding relationships between organisms in an ecosystem.

A relationship between two species in which one species, the parasite, benefits from the other species, the host, which is harmed.

A large region characterized by a specific type of climate and certain types of plant and animal communities.

An area of land that is periodically underwater or whose soil contains a great deal of moisture.

An area where fresh water mixes with salt water from the ocean.

Precipitation that flows over the land and into streams and rivers.

Catching or removing from a population more organisms than the population can replace.

A human-made structure that is built or placed underwater for the purpose of replacing depleted or of enhancing existing coral reef ecosystems.