ANTHRBIO 201 1st Edition Lecture 7A. sex isn’t the only drive for reproduction; forces of evolutionary change 1. natural selection 2. mutation 3. migration 4. genetic drift II. Mutation A. ultimate source of genetic variability B. point mutation 1. single base pair change for the proteins C. Physical basis of mutations: chromosomal deletions 1. 12345 → 1245 2. insertions, deletions, rearranging D. Mutation rates 1. measured in events per base pairs per generations (u) 2. human u: 1/100 mil. base pairs per generation 3. human genome: 3 million base pairs 4. enough variation to ensure evolutionary process can proceed E. Evolutionary effect of mutations 1. cause slow steady loss of existing alleles 2. change gene frequencies over time, at a slow rate 3. A (u) → a 4. delta p= change in frequency of allele A, p=frequency of allele A 5. minimal impact on changing gene frequencies III. Migration A. gene flow: the movement of genes from one population to another B. Predicated on: 1. dispersal of individuals 2. ability of individuals of the same species to mate C. Significance 1. migration homogenizes and maintains similarities across populations D. Evolutionary Effect 1. can be really large- only takes one These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.2. can produce large changes in gene frequencies over time 3. under certain circumstances it only takes a single migrant to besubstantial E. African Americans 1. west african contribution to individual african-american ancestry is onaverage about 80% IV. Genetic DriftA. changes in gene frequencies that occur through sampling error in finitepopulations B. occurs due to the random effects of sampling variation in small