BIO220H1 Chapter Notes - Chapter 4: Commercial Fishing, Directional Selection, Zygosity
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BIO220H1 Full Course Notes
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Reading article: human-induced evolution caused by unnatural selection through harvest of wild animals. Humans harvest animals w/ phenotypically desirable traits from wild populations: = selection that reduces frequencies individual w/ desirable phenotype, sometimes breed animals w/ goal of increasing frequency of desirable phenotypes. Explore how harvesting affects mating system and modifies sexual selection. Selective removal = genetic change in harvested population if selected phenotype has genetic basis: ex: frequency of elephants w/o tusks increased from 10% to 38, ex: agriculture: use most productive animals/plants as breeding stock: In general in wild animal populations: most desirable individuals harvested, leaves behind less desirable to reproduce + contribute genes to future generation, = harvest of wild populations increases frequency of less desirable phenotypes in wild population. Unnatural selection : undesirable changes observed over time in exploited populations because of selection against desirable phenotypes: unintended natural selection through exploitation: Imposed by human activity and not natural selection. Reduces frequency of phenotypes valued by humans.