A community is composed of all the populations of species that inhabit a specific area. Community ecology studies the interactions between such populations of species. Three important interspecific interactions are predation, competition, and symbiosis. The structure of communities also undergoes change due to abiotic and biotic disturbances, resulting in ecological succession.
Predation: A relationship in which a member of one species, the predator, eats or preys on a member of another species, the prey.
Interspecific Competition: Competition between two or more species for the same resources.
Intraspecific Competition: Competition between members of one species for the same resources.
Symbiosis: A close relationship between two species that may benefit one or both species.
Parasitism: A relationship in which one organism (parasite) benefits at the other organism’s (the host’s) expense.
Mutualism: A relationship in which both species benefit.
Commensalism: A relationship in which one species benefits while the other is not affected.
Ecological Succession: The sequential change over time in the composition of a community.
Primary Succession: Ecological succession that takes place in a previously uncolonized area typically lacking soil.
Secondary Succession: Ecological succession that takes place in a previously colonized area that has been disturbed.
Pioneer Species: The first species to inhabit a previously uncolonized or disturbed area, leading to primary or secondary succession.
Disturbance: An occurrence that changes a community, such as a fire, drought, or animal movement Disturbances help maintain species diversity.
Keystone Species: A species that plays an important role in determining the structure of a community.
Keystone species do not have to be predators or at the top of the food chain. Otters, for example, are prey for sea lions and orcas (killer whales).
Two types of competition:
1. Interspecific competition
2. Intraspecific competition
Communities are constantly changing. Ecological succession is a look at how a community changes over time.