Microevolution and speciation review

Microevolution and speciation review - Microevolution and...

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Microevolution and Speciation: 1. Evolution: changes in lines of descent over time; changes in traits 2. Direct observation: antibiotic resistant bacteria -Fossil record: -traces of past organisms -paleontology: study of fossils -older layers -changes occur over time -homologous structures: similar structure due to common ancestor: forelimbs in mammals -embryonic homologies: post anal tail in vertebrates -or gill bones into inner ear -vestigial organs: remnants of structures of importance -appendix -hip bones in whales -molecular homologies: amino acid sequences in hemoglobin -looking at DNA sequencing -convergent evolution: -distantly related organisms resemble each other -torpedo shape bodies -analogous structures similar structures/different origin (not related at all) -bird wing vs. fly wing 3. Populations tend to produce more offspring than the environment can support -one of Darwin's theories 4. Consequence of potential overproduction -struggle of survival 5. Members of a species show variation 6. Crossing over, independent assortment, fertilization -crossing over: genes exchange on homologous chromosomes -meiosis: prophase I -independent assortment: chromosomes/genes assort independently go into gametes independently 7. Natural selection leads to evolution -organism that is most fit will survive -their offspring will have gene to make it more fit 8. bacteria with genes resistant to antibiotic survive -pass genes to next generation -a few will survive with genes that make them survive and pass to next generation 9. gene pool: number of alleles in population (2 alleles per organism possible) -allele frequency: how common the allele is the population A vs. a (A=p, a=q) 10. Evolution is a change in allele frequency over time 11. species: organisms that can interbreed and produce viable and fertile offspring
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