BIO 2129 Lecture Notes - Tropical And Subtropical Moist Broadleaf Forests, Insular Biogeography, Island

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Climate important, but other factors (soil fertility, fire) influence structure+vegetation of area. A species found only within certain regions is endemic to region (ex vascular plants of madagascar b/c of water barriers) Biotas of major biogeographic regions are very different from eachother. 3 scientific advancements changed biogeography: acceptance of continental drift theory. Linnaeus believed all organisms created in one place (paradise) from which they dispersed, and organisms distributed b/c of massive dispersal. Wegner: continental draft; continents changed position over time. 280,000,000 yrs ago, continents united to form single land mass (pangaea), then began to separate, and species evolved: development of phylogenetic taxonomy. 2 processes: immigration of new species, extinction of species already present. Thus, eq. is dynamic b/c if either rate fluctuates, the eq. numbers shifts up or down. We expect: extinction rates to be higher on small island than large ones b/c species populations are smaller; fewer immigrants to reach distant islands.