BS 110 Notes 12-6-2010

BS 110 Notes 12-6-2010 - BS 110 Notes 12-6-2010 What...

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BS 110 Notes 12-6-2010 What determines the number of species in a community? What factors are involved in the changes in community Equilibrium hypothesis of Island biography Balance between rate at which new species immigrate to an island and rate at which species present become extinct Although species number is in equilibrium, species composition is not and may change through time Mangrove islands off coast of florida remove species off these islands very specific experiment Island size and its distance from a source of colinzers = most important factors Distant islands have fewer species that isnlands closer to the mainland due to lower rates of immigration Smaller islands reach species equilibrium with a smaller number of species faster than larger islands because extinction rates are higher on smaller islands Bottom Up Model – mineral nutrients (N) control everything that’s above it Top-Down model – predation drives the trophic levels in this model Two hypotheses that provide explanations on what factors structure communities
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BS 110 Notes 12-6-2010 - BS 110 Notes 12-6-2010 What...

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