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Lecture 12 Community Structure And Biodiversity. Mainland & Marine patterns. Number of coexisting species is highest in the tropics . The number systematically declines from the equator to the poles. What are the causes?
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Mainland & Marine patterns • Number of coexisting species is highest in the tropics. • The number systematically declines from the equator to the poles. • What are the causes? • resources availability is greater and more reliable in the tropics than elsewhere. • species diversity might be self-reinforcing. • over geologic time, speciation rates in the tropics exceeded those of extinction rates.