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Biology 110Exam 3 Study GuideEvolution and its genetic basisAssignmentAudesirk, Audesirk & Byers Selections from Chapters 14-16 & 18Background and reviewFigure 14-7Homology LimbComparative anatomy, embryology, biochemistry, molecular biologyHomology - common descentforelimbs: bat (also pterodactyl, bird - fly)dolphin (also seal - swim)dog (also sheep - run)human (also shrew - grasp)Figure 18-6Divergent (vs. convergent evolution)Phylogenetic tree Eukaryote evolutionisolating mechanismsRemember, species can reproduceFigure 16-10speciation in the same area (sympatric) Figure 16-9and in different areas (allopatric). There are also other .STORYMoths use sex attractant pheromones from female sensed by big feathery antennae in males.These may be molecules like acetates, chains10 to 15 carbons long.Two similar moths in same place (sympatric) do not mate, thus seem to be 2 species (Roelofs and Comeau, Science 165, 398-400, 1969).One uses molecule cis around one double bond, the other trans.For that to happen, one female would have to change pheromone used and a male at the same place and time would have to have a change in preference, an amazing jump (saltation).Divergent evolutionFigure 23-1Comparative anatomy, embryology, biochemistry, molecular biologyFigure E18-1can use "molecular" (biochemical) data to get relationships Figure 14-11also (cytochrome c sequence comparison between species)Figure 24-1
Remember (and it is so confusing that it is hard to remember) that lower on the diagram are ancestors, not "simple" organisms that are around today. Figure 24-2One "left-over" that helps to confuse this issue is the old saying "Ontogeny recapitulates phylogeny." Gill pouches and tail suggest that people and birds go through a fish stage in their development.Need to simplify by considering one geneBox (a closer look)The Hardy-Weinberg principleFigure 12-11Hey, this looks like a punnet square for the F2 of a cross with one gene and two alleles, except here, we have added probabilities of the two alleles (p + q = 1) to get probabilities of the "4" genotypes (actually 3 since aA is the same as Aa)"Adaptive significance," "selection pressures" and all those favorite jargons give the false impression that everything is the way it is because of "deliberate" outcomes of evolutionary processes. But all kinds of things got to be the way they are through "accidental" processes. (Furthermore, evolution cannot make an overall master plan but rather has to build on the successes and mistakes of the past.)Figure 15-5Genetic drift The frequency of alleles might change by this seemingly accidental mechanism.