BIOLOGY 1M03 Study Guide - Final Guide: Keystone Species, Pisaster, Primary Succession
13 Apr 2013
School
Department
Course
Professor
Document Summary
Are +/+ interactions that involve a wide variety of organisms and rewards. Most critical of all mutualisms occur between bacteria that fix nitrogen and certain species of plants. Mutualism benefits both species, but the interaction does not involve individuals from different species being altruistic. The benefits received are a by-product of each individual pursuing its own self-interest by maximizing its ability to survive and reproduce. The structure of a community can change dramatically if a single species of predator or herbivore is removed from or added to a community. A keystone species is a species that has a much greater impact on the surrounding species than its abundance would suggest. For example, the sea star pisaster is a keystone species in some intertidal areas. When pisaster was removed from experimental areas, the number of species present and the complexity of the habitat changed radically. Community composition and structure may change radically in response to changes in abiotic and biotic conditions.
