Study guide Chaps 7 8 Freeman and Herron ZOO 206 1 Describe gene flow and how the northern water snakes in Lake Erie show a balance between gene flow and selection How would genetic differences between populations be affected if gene flow among them happened at very high rates 2 Define genetic drift and describe under what circumstances it has its greatest effect on frequencies of alleles If only genetic drift is affecting a locus what will eventually happen if there are just two alleles for locus the 3 Describe how the colonization of New Zealand and other islands by Silvereyes represents an example of genetic drift Describe what the bottleneck effect is and give an example 4 What is the relationship between a change in the proportion of heterozygotes and population size i e be able to explain the formula Hg 1 Hg 1 1 2N In the experiment in which 107 populations of D melanogaster were established generation by generation by randomly choosing 8 males and 8 females for each generation for each population what was apparently paradoxical about the decline in heterozygosity What s an apparent explanation s 5 Define Effective Population Size Describe how various factors can affect Ne 6 What is the coefficient of inbreeding F What is the relationship between heterozygosity of an inbred population and that if a random mating population i e explain the formula HF HO 1 F 7 Be able to explain how to calculate F for a particular set if relatives 8 Describe the potential effects in inbreeding depression Why do we think inbreeding depression has such effects 9 Describe the hypothesis why we think the Greater Prairie Chicken populations in Illinois declined even after more habitat was made available What is the evidence that supports that hypothesis 10 What is the hypothesis for why there is greater genetic differentiation across geographic distances for Y chromosome loci compared to either autosomal or mitochondrial loci in humans 11 What is linkage disequilibrium and what is the evidence that any two loci may be in a state of linkage disequilibrium What potential impact does linkage disequilibrium have on the outcome of natural selection for one allele at one locus 12 What are the costs associated with sexual reproduction 13 Describe John Maynard Smith s model for the reproductive success of individuals reproducing sexually and asexually What assumptions are made in his model and does the model seem to be supported by what we observe in nature with regard to mode of sexual reproduction i e sexual versus asexual 14 Describe the experiment in which asexual reproduction is simulated in flour beetles what did the outcome suggest about the relative advantages of sexual and simulated asexual reproduction in the context of natural selection What factor did not exist in the control experiments 16 Describe Muller s Ratchet and how it might affect asexual lineages How is Muller s Ratchet broken 17 Describe the apparent forces that favor the maintenance of sexual reproduction in many species Include in your answer a description of the Red Queen hypothesis and discuss reproduction of snails in New Zealand and their rates of parasitism by trematodes What is one alternative explanation for the higher rate of sexual reproduction i e proportion males in populations with higher rates of trematode infection