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Biol 250 Midterm 2 Review (chapt 25,26,27,50)

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University of Waterloo
BIOL 150
Kirsten Muller

Bio 250 Midterm 2 NotesChapter 25 Evolutionary Processes 1Genetic Driftsmall population size random according to fitness and does not result in adaptation can lead to fixation or loss of allelesfounder effecta change in the allele frequencies that occur when a new population is establishedgenetic bottlenecksudden reduction in the number of alleles in a populationex forked bristle either lost or fixed in fliesex genetic bottlenecksPingelap Atoll only 20 people survived and now 20 are colourblindex Amish with the Ellisvan Creveld Syndrome 6 fingers2Gene Flowmovement of alleles from one population to another and breeding with the new population can homogenize allele frequencies between 2 populations random with respect to fitnessex lupines near volcano immigration3Mutationrestores genetic diversity creates random new alleles equally likely to produce a deleterious or advantageous alleleonly has an impact over a very long period of time or over numerous generationsalleles that change phenotype are exposed to natural selectioncan directly measure the rate at which a visible mutant phenotype arises in a labhumans have a mutation rate of 11 new alleles per generationmutation rates vary among individuals species and genes4Nonrandom Matinginbreeding and sexual selection violates this principleinbreeding lowers fitness dramatic reduction in the number of heterozygotes variation increasesinbreeding does not cause evolution because allele frequencies do not change in the population only the frequency of genotypes but can speed the rate of evolutionary change sexual selection occurs because eggs are expensive and sperm are cheapcan act heavily on males because of female choosinessex male zebra finches with orange beaks indicate they are fed more carotenoidscan lead to malemale combat or sexual dimorphism differences between male and female traitsChapter 26 SpeciesSpeciation DNA barcoding takes a single gene and uses it as a barcode to identify a speciesKingdomPhylumClassOrderFamilyGenusSpeciesremember kinky people come over for group sexspeciation creation of a new species occurs from reduced gene flow as a result of mutation natural selection and genetic drift allelic frequencies and other characteristics of the independent populations divergespecies evolutionary independent population or group of populationsbiological species conceptreproductive isolation means its a separate species no gene flow occurs either prezygotic or postzygotic factors limit reproductive successmorphospecies conceptindependent species are identified by differences in size shape or other morphological features
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