Biology (B)

Lesson Summary

• A community is the biotic part of an ecosystem. It consists of all the populations of all the species that live in the same area. It also includes their interactions.
• Predation is a relationship in which members of one species (the predator) consume members of another species (the prey). A predator-prey relationship keeps the populations of both species in balance.
• Competition is a relationship between organisms that strive for the same resources in the same place. Intraspecific competition occurs between members of the same species. It improves the species’ adaptations. Interspecific competition occurs between members of different species. It may lead to one species going extinct or both becoming more specialized.
• Symbiosis is a close relationship between two species in which at least one species benefits. Mutualism is a symbiotic relationship in which both species benefit. Commensalism is a symbiotic relationship in which one species benefits while the other species is not affected. Parasitism is a symbiotic relationship in which one species (the parasite) benefits while the other species (the host) is harmed.
• Ecological succession is the process in which a community changes through time. Primary succession occurs in an area that has never before been colonized. Secondary succession occurs in a formerly inhabited area that was disturbed.