Ch 4, 5, 6, 7

Ch 4, 5, 6, 7 - 1. Ch 4 Modern Synthesis and Population...

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1. Ch 4 Modern Synthesis and Population Genetics a. Modern synthesis between Darwin and Mendel combines natural selection, Mendelian genetics, and new information from molecular genetics and population biology b. Population: a group of interbreeding individuals of a species in the same area c. Population genetics: how changes in gene frequency are affected by evolution d. Evolutionary forces work at different organizational levels i. Mutation: DNA and Chromosomes random mistakes in DNA replication, only mistakes made during meiosis are heritable ii. Natural selection: Individual organisms iii. Gene flow and genetic drift: Populations gene flow: movement of genes between population (ex: immigration, migration) genetic isolation: physical (like mountains or islands) or cultural barriers -allopatric isolation genetic drift: evolutionary change produced by random factors. the smaller the population, the more some individuals contribute a large share of the genes *a “rare” gene can be passed to a large number of descendents * alleles can disappear Ex: Founder effect: the establishment of a new population by only a few founders (ex: Amish and polydactyl (a symptom of Ellis von Orewald)) e. Polygenic, continuous, discrete traits i. Polygenic traits: are continuous, controlled by alleles at two genetic loci with each locus making an additive contribution (ex: eye color, hair color) ii. Continuous traits iii. Discrete Traits: Mendelian traits. controlled by alleles at one locus. no overlap for phenotypes f. Sickle Cell Anemia pleiotropy (a single gene with multiple effects) causes some blood cells to collapse into a sickle shape when deprived of oxygen homozygous recessive (ss) has anemia heterozygous (Ss) is slightly anemic but has a better malaria resistance 2. Ch 6 and 7 Primates a. Primitive vs. Derived traits i. primitive—older ancestral forms ii. derived—shared narrowly, relatively recent, imply a close relationship, useful for
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Ch 4, 5, 6, 7 - 1. Ch 4 Modern Synthesis and Population...

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