under the bscthe central problem of speciation is

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Unformatted text preview: from other such groups." Under the BSC…”the central problem of SPECIATION is understanding the origin of isolating barriers* that actually or potentially prevent gene flow in sympatry.” (Coyne and Orr 2004). *isolating barriers = phenotypes, e.g. behaviors! 8 9/19/13 Can behavioral barriers initiate speciation? Can behavioral barriers initiate speciation? YES 9 9/19/13 How do we study speciation? ! (Shaw and Mullen 2011)" " •  Axes of differentiation—will tell us all the ways that closely related species differ" •  Speciation phenotypes—will tell us which phenotypes prevent gene flow" •  Forces of differentiation—will tell us why these phenotypes evolved (diverged)" •  Genetic architectures of speciation—will tell us what underlying genetic changes occurred" •  The evolution of species boundaries—will tell us how speciation phenotypes trigger further genome evolution" Speciation model for Laupala crickets Axes of differentiation Speciation phenotype Divergent acoustic behavior! ! ! Reduced interbreeding between populations due to acoustic differences ! ! ! Reproductive isolation! Hypothesizes that acoustic evolution causes " speciation in Hawaiian crickets 10 9/19/13 Some Natural History Hawaiian Islands are super isolated! And a great laboratory for the study of speciation: Geology and Evolution Direction Of Plate Movement 11 9/19/13 Some Natural History (2.6-3.7 my)! (5.1 my) (0.75-1.9 my) (0.43 my)! Some Natural History R. C. L. Perkins (British Museum) Dan Otte (Philadelphia Academy) Genus Laupala (swordtail crickets) before 1994: 1 species formally recognized after 1994: 38 species formally recognized 12 9/19/13 L. cerasina 100 94 Laupala 100 97 L. fugax 98 Molokai! Maui! Oahu! L. melewiki 91 100 73 Kauai! L. eukolea 100 65 L. spisa 100 L. neospisa 71 L. hapapa L. oahuensis Hawaii! L. pacifica 100 Laupala AFLP NJ tree/bootstraps 1048 characters L. hualalai 100 95 L. pruna 100 6...
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