Ethan Kupferberg 9/27/19What does evolution mean?Change in allele frequency over time Which evolutionary mechanisms can cause allele/genotype frequencies to change?Assortative- random dating (similar continuous mate)-> increased frequency of homozygotesPoint mutations: Frameshifts, silent, missense, nonsense Chromosomal mutations: deletion, duplication, inversion, reciprocal translocationWhat is the difference between point and chromosomal mutations?A change with a single nucleotideNon-disjunction occurs during meiosis (leads to aneuploidy and polyploidy)Genetic Drift vs Gene flow Both are random changes, but genetic drift happens in a population gene flow flows allele from one population to another.genetic drift can lead to a reduction in genetic variationGene flow introduces new alleles and increases variation Both cause hominizationGenetic drift is all about sample size Natural selection Variation in population Variation leads to variation individuals Variation must be heritableNatural selection is the only adaptive forceBalancing selection Heterozygote advantage maintains heterozygotes in populationSpecies concept Forces differentiating populations: Selection, drift, mutation, assortative mating Alloptric speciation: dispersal, isolation varence, missing link, allopatric means separateSympatric selectionPolyploidy Adaptive radiation: Multiple species evolving from a common ancestor Monophyly is a single linage including common ancestor and all that evolve from that ancestorParaphyly one of the descendants not included in the
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