cheatsheettest2 - Some changes in DNA leads to changes in...

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Some changes in DNA leads to changes in traits. Changes in traits should be evidence of changes in DNA Individuals don’t evolve, groups do. A species’ genetic component changes as the individuals reproduce, changes based on how DNA changes and who reproduces. Individuals are selected and variation must exist in the population. Species-evo. Def. a population sharing genetic information (in nature) Natural selection-individuals that are most successful at reproducing will pass on more of their genetic information o Reproductive success is a measure of evolutionary success, environment determined Memes-Transmissible ideas o Ideas act similarly to genes: contain info, replicate w/ imperfect fidelity, most successful replicators become most abundant Contrast—genes:memes,slow rep:rapid rep, high fidelity:low fidelity, universal in all organisms:not universal Evolution of memes and genes o Selection of memes and genes can be at odds (energy required to transmit memes lessens lifespan) o Priest-power to pass memes, no reproduction o Soldier-power to pass memes, life at risk o Memes-can be bad quality and still get passed on successfully Human population growth and ability to share information—hand-in-hand Artificial selection-individuals chosen by humans will reproduce and pass on genetic information (Teosinte [6 kernals]->Maize Evolution must have: genetic diversity to give rise to individuals with different traits, and not all individuals can reproduce Type of selection o Directional-individuals with one extreme of a train cannot reproduce as well as individuals with the opposite extreme of the trait, average moves towards the successful extreme ex) body size of swallow->bigger body o Stabilizing-both extremes become disadvantageous, less diversity, more near original average ex)birth weight in humans o Disruptive-both extremes become advantageous, average becomes disadvantageous—two groups form ex)black bellied seed crackers beaks Random evolution o Genetic Drift-some reproduce, some don’t; all equally able to produce—random chance for those who do o Bottleneck—bottlenecking event causes dramatic decrease in population (fire, earthquake, dramatic event) Decrease in genetic diversity, some alleles wiped out, shift in percent of certain pheno/genotypes o Mutations—1 in a billion, mutations have to survive drift and natural selection Mitochondrial DNA passed by mother only Out of Africa Hypothesis-homoerectus emerged in Africa 1-2milya then migrated, homosapiens emerged 100kya in Africa, then migrated and displaced homoerectus o Relationships of diff pops and individuals using mtDNA shows 150k yrsago since split o Disproved by parts of DNA other than mtDNA Multiregional hypothesis-“ “, homosapiens independently evolved in the different locations into different types of homosapiens o Disproved by mtDNA Major difference is when we last had a common ancestor Mutation rate mtDNA 1 per 20000yrs, 1 nucleotide diff between two people—common ancestor 10000yrsago
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This note was uploaded on 04/06/2008 for the course BIO 311D taught by Professor Reichler during the Spring '08 term at University of Texas.

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cheatsheettest2 - Some changes in DNA leads to changes in...

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