1Macroevolution* (Ch. 24.3 and parts of other sections)*evolutionary change at or above the species levelMany can accept microevolution but not macroevolution(e.g. Michael Behe, The Edge of Evolution, 2007)2From Speciation to Macroevolution•Macroevolution is the cumulative effect of many speciation and extinction events3The Modern Synthesis•Established in the 1930s and 1940s•Connected the units of evolution (genes) with the mechanism of evolution (selection on populations)•Integrated Darwinian evolution with Mendelian genetics+4Architects of the modern synthesisJBS HaldaneG Ledyard StebbinsTheodosius DobzhanskySewall Wright(no need to memorize these guys)
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5Natural selection is the primary mechanism of adaptive evolution•Natural selection accumulates and maintains favorable genotypes in a population•Depends on existence of heritable, genetic variation6Populations evolve, individuals do notIn case you didn’t get that…Populations evolve, individuals do not7Evolutionary Processes•Mutation and sexual recombination produce new variation•Selection, drift and gene flow alter a population’s genetic composition8Mutations•The raw material of evolution•A “two edged sword” - most mutations are deleterious but a few are beneficial and these provide the basis for evolutionary changeA partial list of kinds of mutations•Point mutations•Insertions / Deletions•Gene duplications•Chromosome inversions•Polyploidization