BIO 182 Lecture Notes - Lecture 29: Superorganism, Species Richness, Insular Biogeography

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4 Nov 2016
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Keystone predators: increase species diversity by preventing domination of another species, speciation and competition are linked. Equilibrium community: diversity regulated by available resources and habitats, constant availability. Spatial disequilibrium constant change in species pool. Temporal disequilibrium disruption of climax state (equilibrium) Island biogeography larger islands that are closer to the mainland have more species richness (not necessarily real islands) Species in that exist in an area either evolved there or immigrated there. Richness will return to about the same after all species are removed. Migration needs to be possible in order to preserve richness. Disturbances: discrete killing event, density-independent, low and high levels lead to low diversity. Low levels lead to less diversity because one single species can easily dominate. High levels lead to less diversity because of how common disturbances are: intermediate levels have the most diversity, regime. Succession species composition changing over time: primary new habitat is exposed, secondary original habitat is disturbed, early species.