eemb_113_lecture_6_notes - Lecture 6 speciation \u25cf How do we identify species \u25cb Mayr(1942 \u25a0 Biological species concept \u25cf \u201cSpecies are groups of

eemb_113_lecture_6_notes - Lecture 6 speciation u25cf How...

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Lecture 6 - speciation How do we identify species? Mayr (1942) Biological species concept “Species are groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups” This statement does not apply to asexual organisms or extinct stuff (fossils) “Interbreeding” is most conflicting phrase Allopatric speciation Vicariant speciation - origin of species results from geographic separation of previously interbreeding populations Peripatric speciation - origin of species results from geographic separation of a small peripheral subpopulation of the previously interbreeding populations Divergence is expected to be linked to a strong selective gradient What makes an effective barrier to gene flow? Formation of mountain, continental drift Ex. Indotyphlidae - continental drift around India and Africa Initial time step
Time step - if hybrid’s fitness is low: Reproductive isolation Indotyphlidae Different species found on 2-10 different islands Biogeography - western North America

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