BIO220H1 Chapter Notes - Chapter 3: Bighorn Sheep, Heritability
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BIO220H1 Full Course Notes
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Reading article 3 unnatural selection (nils chr. Meta-analysis of previously published data: authors compare rates of phenotypic changes in 40 populations subject to human harvesting. High rates of change in these harvested populations: higher than changes from natural agents by 300% Changes in: morphological traits, life-history traits (reproductive age) Can have phenotypic changes in 2 ways: genetic (evolutionary, plastic (ecological) Population recovers more slowly from genetic than from plastic change: genetic change might be irreversible. Harvesting pressure on larger + older individuals: juvenescence of populations, increased variability in abundance, reduced genetic variability. Harvesting-induced changes more significant than changes from other sources: r = h2s. S = selection differential (strength of selection: in harvesting selection s is higher than from other sources (i. e. natural selection) Because mortality rates from hunting/fishing > natural mortality rate.
