Biology 3445F Lecture Notes - Lecture 9: Biogeography, Species Richness, Dynamic Equilibrium
15 Nov 2016
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Document Summary
Organisms exhibit non-uniform distribution patters, both in space and through time. Biogeography study of these patterns and the many factors using them. The environment often determines which species are able to live where (niche) These is also an element of chance events (neutral) Gradual change from one system to another without a sharp boundary. Little or no gene flow to dilute effect of selection/mutation. Neutral theory; differences b/n species are ignored. Richness is a function of the balance b/n immigration and extinction. # of species found on an island is the balance b/n immigration and extinction immigration rate = # of new species colonising. Extinction rate = # of species already on the island going extinct. Equilibrium number of species is where the two lines cross. Is a sta(cid:271)le (cid:271)ut dy(cid:374)a(cid:373)i(cid:272) e(cid:395)uilibrium. Island size and distance -> i & e & . Is (cid:396)oughly (cid:272)o(cid:374)sta(cid:374)t th(cid:396)ough ti(cid:373)e (cid:894)sta(cid:271)le(cid:895) Large islands support more species than small islands.
