Community (ecology)

In ecology, a community is the living things in a place. It may mean a group of living things that are not dependent on other communities. It may mean a small group, such as the living things in a piece of dead wood.^[1] Populations of many species make up a community. A community with its physical and chemical environment makes an ecosystem. Each population may have an effect on other populations in the community in different ways (called symbiosis).^[2]

In consumption, one living thing eats another. Three kinds of consumption are predation, herbivory, and parasitism. In predation, one animal, the predator, kills and eats another animal, the prey. In herbivory, an animal called an herbivore eats a plant, either in part or in whole. In parasitism, a parasite lives on another living thing, the host. The parasite eats small parts of tissue or nutrients from the host, but usually does not kill it.

In competition, two living things, from the same or different species, both need the same resources. If one species is better at getting the resources, the population of the other species may die out. Competition may have a negative effect on both species. In mutualism, two species both help each other, so they have a positive effect on each other. In commensalism, one species is helped, but it has no effect on the other species.^[3]

• Prey-predator equations