BIOL211#26 - Chapter 58 Community Ecology A community is an...

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1 Chapter 58 Community Ecology A community is an assemblage of many populations that live in the same place at the same time Communities can occur on a wide range of scales A community can be nested within another community Views of Communities Ecologists have long held differing views concerning community structure – Organismic model Views a community as a superorganism – Individualistic model Views a community as an assemblage of species distributed independently along an environmental gradient Principle of species individuality – Each species is distributed according to its physiological needs and population dynamics – Most communities intergrade, or merge into one another gradually – Competition does not create distinct vegetational zones Principle of species individuality Figure 58.1
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2 Species Richness Species richness – The number of different species in each community Varies along a latitudinal gradient, generally increasing from polar areas to temperate areas Also influenced by topographical variation Species richness Figure 58.3 Latitudinal gradient of species richness – Time hypothesis – Area hypothesis – Productivity hypothesis – Intermediate-disturbance hypothesis The time hypothesis – Temperate regions have less species rich communities because they are younger
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This note was uploaded on 10/02/2011 for the course BIOL 211 taught by Professor Boury during the Spring '08 term at Iowa State.

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BIOL211#26 - Chapter 58 Community Ecology A community is an...

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