Bio1B Evolution 9 Ensatina eschscholtzii One ring species Or 2 biological species Or 11 Phylogenetic species Last lecture Evolution of sacrifice altruism Species speciation What is a species anyway Pp 487 492 Concepts typological biological phylogenetic Reproductive isolation mechanisms Easy one Humans living relatives Today Species speciation What is a species anyway Pp 487 492 Interesting one Ensatina salamanders Speciation processes Pp 492 504 Losos Rickleffs 2009 paper Introduction geographic modes Adaptive radiations Hybridization hybrid zones reinforcement hybridspeciation 1 k e overlap hybrids k e overlap no hybrids 2 Allopatric sister species among northern montane Cophixalus Hoskin 2004 Geographic modes of speciation exiguus v aenigma exiguus 5 mtDNA divergence aenigma Large body size lower freq call in aenigma bombiens saxatilis concinnus v monticola 5 mtDNA divergence concinnus has lower longer call distinct morphology Futuyma 2005 3 concinnus monticola hosmeri 4 Sympatric speciation on remote islands eg Lord Howe Island palms Howea Savolainen et al 2006 Nature 441 210 214 Recently 1Mya formed sister species ecologically distinct and with divergent flowering time despite high gene flow across the range of each species on the island Parapatric evolution of reproductive isolation over a very short distance in the grass species Anthoxanthum odoratum 5 Futuyma 2005 Calcareous soils 6 Adaptive radiations pp 524 5 Peripatric speciation paradise kingfishers in New Guinea Mayr Rapid speciation with ecologically driven divergent selection Common on remote islands or other novel environments following colonization Promoted by isolation ecological opportunity Processes Founder event drift selection Futuyma 2005 Flowering time 7 e g Hawaiian silverswords Fig 25 18 Other examples African cichlids Hawaiian arthropods Andean lupines Carribean anole lizards etc etc 8 Speciation on islands Losos Rickleffs 2009 Adaptive divergence among or within islands Hybrid zones alternative outcomes length Adaptive divergence of bill dimensions width depth Or new hybrid species Fig 24 14 9 Hybrid zone Bombina variegatabombina Fig 24 13 11 10 A stable hybrid zone in Ensatina Alexandrino et al 2005 20 yrs later 12 Recent 8kya expansion from long isolated 2 Myr refugia in the NE Australian rainforest Is there evidence for reproductive isolation Many hybrid zones Is there evidence for reinforcement prezygotic isolation Skink narrow 1km hybrid zone random mating but some selection against hybrids Small marsupial random mating hybrid swarm Moritz et al 2009 PRSL Frog reinforcement Reproductive isolation 13 Adaptive shifts via hybridization diploid vs polyploid Hybrid speciation Formation of unique and 14 Polyploid hybrid Review Mallet 2007 Nature 446 279 283 isolated lineages from interlineage hybrids Allopolyploidy see p 496 If same ploidy requires ecogeographic isolation from parent lineages E g arid adapted Helianthus anomalus H annuus X H petiolaris Parent species 2 Fig 24 18 p 503 Phenotype 15 Parent species 2 16
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