BISC 313 Lecture Notes - Lecture 11: Pisaster, Omnivore, Keystone Species
1 Nov 2017
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Document Summary
Communities are groups of interacting species that occur together at the same place and time. Usually defined based on physical or biological characteristics. Often defined arbitrarily, based on the questions that are being posted. Boundaries do not necessarily encompass all organisms, mostly out of practical necessity. Taxonomic affinity: all closely related species in a community. Guilds: group of species that use the same resources, typically at the same trophic level. Functional group: species that function in similar ways, but do not necessarily use the same resources. Some species span two trophic levels, and some species change feeding status as they mature. Omnivores: feed on more than one trophic level. May be represented by organisms which eat both plants and animals (traditional omnivory) or by organisms that eat animals from two different trophic levels (trophic omnivory) Food webs exclude non-trophic interactions (horizontal interactions, such as competition, mutualism)
