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Speciation I. Microevolution and macroevolution II. Patterns of descent III. Species concepts A. Biological species B. Ecological species C. Morphological species D. Phylogenetic species IV. Barriers that lead to speciation A. Prezygotic B. Postzygotic V. Modes of speciation A. Allopatric speciation B. Sympatric speciation II. Patterns of descent A. Anagenesis B. Cladogenesis III. Species concepts A. Biological species ‘Species are groups of actually or potentially interbreeding natural populations, which are reproductively isolated from each other.’ Mayr Reproductive isolating mechanisms (RIMs) B. Ecological species niche C. Morphological species D. Phylogenetic species • A species consists of a population or group of populations that share a common evolutionary fate through time. Fossil record • Molecular clocks DNA - DNA hybridization 98.7% 99.2% III. Species concepts Problems with definitions • convergent evolution • asexual species • promiscuous • ecotypes • fossil record Link IV. Barriers that lead to speciation A. Prezygotic barriers 1. Habitat isolation 2. Behavioral isolation • sexual selection Sage grouse Songbirds A. Prezygotic barriers 3. Temporal isolation 4. Anatomical isolation 5. Gametic isolation • diurnal, nocturnal, crepuscular B. Postzygotic barriers wheat rye Hybrid problems mules tritical V. Modes of speciation A. Allopatric speciation Bird species A. Allopatric speciation Fruit flies Founder effect Darwin’s finches Beak of the finch B. Sympatric speciation Polyploidy in plants • autopolyploid 2N X 1N • allopolyploidy Goatsbeard VI. Punctuated equilibrium • Allopatric model • tempo of PE VII. Evolutionary novelties Exaptations Feathers and bones Evo-devo Genes HOX genes Gene regulation The end
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