BS 182H Lecture Notes - Lecture 6: Assortative Mating, Species Problem, Allopatric Speciation
17 Mar 2016
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Species: darwin ! people who make many species = splitters, people who make few species = lumpers, species = artificial construct, biodiversity = genotypic and phenotypic differences, ancestor ! descendants; if diversity is desired, then there is a need for separation/interruption of gene flow, prezygotic and postzygotic, example: birds can predict when caterpillars will come to determine when it is best to lay eggs, france gene flow retards. Cichlids: monophyletic = closely related/sister species, fish = in the process of speciation, large inshore species and small pelagic species, different foods, highly restricted gene flow between the forms, suggesting reproductive isolation between them, for size, there is assortative mating. Idea of what constitutes a species is not truly settled: the biological species concept is the textbook definition, word species means a different kind, reproductive continuity within species and discontinuity of variation between species = important, species evolve and give rise to new species (speciation, also varieties within species.
