BIO 124 Lecture Notes - Lecture 4: Gradualism, Binomial Nomenclature, Exon Shuffling
21 Mar 2016
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Document Summary
Why are zebras stripy???: temperature can successfully predict stripe patterns. In areas with the lowest seasonal temperatures, zebras have fewer and fainter stripes. The selective agents driving zebra striping are probably multifarious and complex. Geography of speciation: allopatric speciation speciation due to geographic isolation. Lack of geographic isolation can limit allopatric speciation and adaptive radiation. Peripatric speciation when peripheral populations become geographically isolated from the main population and undergoes speciation and genetic divergence. A form of allopatric speciation that takes into account the founder effect. Theoretical foundation for punctuated equilibrium: parapatric speciation. Divergence is due to reduced gene flow and difference in selection pressures across the population range. Speciation due to different selection pressures in a heterogeneous environment over a single geographic range. Example: plants in soil with different levels of metal: sympatric speciation. Dietary differences in the same geographic location. When speciation happens without any geographic separation. Example: polyploidy occurs and therefore instantaneous complete speciation happens.
