Biogeography 05

Biogeography 05 - • cross section of North America A...

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BIOGEOGRAPHY Biogeography = The global distribution of organisms Exotic species - non-native, introduced (Cane Toads, Kudzu) Endemic species - native to an area Cosmopolitan species - found wherever appropriate habitat exists (mice) Ubiquitous species - found everywhere (rats, humans, cockroaches) Wallace’s Realm’s Nearctic, Neotropical, Palearctic, Ethiopian, Oriental, and Australian Now called biotic provinces, region inhabited by characteristic set of taxa Biogeography and evolution: Convergent evolution: similar conditions produce similar ecosystems and organisms with similar adaptations (e.g. dolphins and sharks) Divergent evolution (adaptive radiation): evolution of new species from a common ancestor but subject to different selection pressures ( mammals) Biomes: type of ecosystem with characteristic climate and biota Longitudinal patterns, from tropics to poles Altitudinal patterns, elevation
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Unformatted text preview: • cross section of North America A Closer Look 8.1 Island Biogeography (island = any isolated habitat) • Islands have fewer species, high endemism, lower diversity, higher rate of extinction • Species richness is directly proportional to island size, inversely proportional to distance from mainland • What can we learn from island biogeography? • fragmentation of the landscape (through urbanization, forestry, agriculture, roads) creates ecological islands • Species that need large habitats may not survive on "islands” • Species – area curve: used to predict extinction rates and to plan for conservation of habitat • When exotic species are introduced, what happens to native species? BIOGEOGRAPHY Figure 8.6 from page 137 in text showing the pattern of vegetation in relation to precipitation and temperature. Boundaries between types are approximate....
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Biogeography 05 - • cross section of North America A...

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