BIOL 3600 Lecture Notes - Lecture 8: Selection Coefficient, Melanism, Allele Frequency
Document Summary
Mechanisms of evolution: mutation, selection, migration, genetic drift. Testing for departures from hw equilibrium: chi square test with 1 degree of freedom, chi square (x^2) > 3. 84 indicates statistical significance (pvalue < 0. 05) Industrial melanism: white and black moths, lichens were common before industrial revolution white moths were more camouflaged and were about to reach fixation. Industrial revolution killed off lichens and black/dark moths were more easily camouflaged. Selection of quantitative trait: positive correlation between parent offspring traits due to heredity, election causes distribution of trait values to change, mean value of trait in offspring. Selection can affect many life history traits: zygotes adults parents gametes zygotes, fertilization success, viability, mating success, fecundity. Beware of adaptive storytelling: be careful when claiming natural selection has occurred, sometimes demographic or neutral processes van mimic selection, allele surfing as populations expand over geography populations extend.