APES Key Terms

Community ecology

The study of interactions among species.

Symbiosis

Two species living in a close and long-term association with one another in an ecosystem.

Biosphere

The region of our planet where life resides.

Competition

The struggle of individuals, either within or between species, to obtain a shared limiting resource.

Competitive exclusion principle

The principle stating that two species competing for the same limiting resource cannot coexist.

Predation

An interaction in which one animal (the predator) kills and consumes another animal (the prey).

Parasitoid

A specialized type of predator that lays eggs inside another organism (a host); the larvae then hatch and consume the host from the inside out.

Parasitism

An interaction in which one organism lives in or on another organism (the host) and consumes a portion of it, usually harming but not killing the host.

Pathogen

A parasite or microorganism that causes disease in its host.

Herbivory

An interaction in which an animal consumes a producer (such as plants or algae).

Mutualism

An interaction between two species where both species benefit (+/+).

Photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water.

Commensalism

An interaction in which one species benefits and the other is neither helped nor harmed (+/0)

Native species

Species that naturally live and thrive in a particular ecosystem without human introduction.

Exotic species

A species living outside its historical, native distributional range due to human activity.

Invasive species

An exotic species that spreads rapidly and harms native species or ecosystems.

Climate

The average long-term weather conditions in a particular area, typically evaluated over at least 30 years.

Weather

The short-term state of the atmosphere at a specific time and place.