Bio1B Evolution 9 Last lecture Evolution of sacrifice altruism Species speciation What is a species anyway Pp 487 492 Reproductive isolation mechanisms Today Species speciation What is a species anyway Pp 487 492 Concepts typological biological phylogenetic Reproductive isolation mechanisms E g Humans relatives Ensatina ring spp Speciation processes Pp 492 504 Introduction geographic modes The DM model postzygotic isolation Adaptive radiations What is a species Typological pre evolutionary eg Aristotle Linnaeus Evolutionary NeoDarwinists Reproductive isolation Biological SC Groups of populations reproductively isolated from others Systematists Character change Darwin Discontinuities DWM extinction Phylogenetic SC Morphological SC Diagnosable clusters with common ancestry molecular or morphological Phenotypically distinct sets of populations Reconciling different perspectives Forms of Reproductive Isolation Prezygotic Separation of mating Gamete recognition Postzygotic Viability F1 or later Fertility Postzygotic RI increases with genetic divergence also Fig 17 5 Increasing RI phenotypic divergence Habitat Timing Behavior Mechanical General lineage concept focuses on the process not how to recognize species Species of Hominidae Pygmy chimp Ensatina eschscholtzii One ring species Or 2 biological species Or 11 Phylogenetic species k e overlap hybrids k e overlap no hybrids Geographic modes of speciation Futuyma 2005 Allopatric sister species among northern montane Cophixalus Hoskin 2004 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 concinnus monticola hosmeri Parapatric evolution of reproductive isolation over a very short distance in the grass species Anthoxanthum odoratum Futuyma 2005 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 Flowering time Calcareous soils Peripatric speciation paradise kingfishers in New Guinea Mayr Processes Founder event drift selection Futuyma 2005
View Full Document
Unlocking...