L41 BIOL 2970 Lecture Notes - Lecture 27: Allopatric Speciation, Richard Goldschmidt, Gradualism
25 Feb 2016
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Sexual forms only deines species as only reproducive species sexual reproducion deliberately excluded asexual organisms. Not temporal dimension assumes that we are studying living species no fossil/evoluionary history. Not a single unit of evoluion noion of having sub species. Oten not pracically testable if you do have two geographically isolated populaions, how do you test the hypothesis that they are diferent species. Phylogeneic species concept (joel cracrat) a lineage of ancestor descendant populaions diagnosably disinct from other such lineages. Sources of allopatry iniially geographic barriers separate two populaions and breaks it into two undergoes separate evoluion and then become recognized as separate species. Vicarience allopatry produced by subdivide a formerly coninuous habitat panama divided the two oceans two separate species on each side formed. Founder event rare dispersal across a pre-exising barrier usually by a small number of individuals to establish a new, geographically isolated populaion. Non-allopatric speciaion speciaion occurring without the geographic allopatry occurring as the irst process.
