Evolutionary Biology 322 Final Exam Questions and Correct Answers

In which location in the genome are transposable elements least likely to experience strong selection? a noncoding area of the genome that experiences little recombination There are 1,200 functional olfactory receptor genes in the mouse genome and only 550 in the human genome. Which of the following is the possible reason? genes that are rarely used can degenerate because of reduced selective pressure Mutations at the third position of the codon are more likely to _____ than mutations at the first or second position - be selectively neutral - be fixed by genetic drift - be synonymous - result in gene product with the similar properties as the original gene What is the best explanation for the observation that eukaryotes that seem superficially simple can have much larger genomes (in terms of mass or number of base pairs) than organisms that have complex anatomy, structure, or behavior? some organisms have tremendous amount of noncoding DNA, like repetitive sequences You perform an in stiu hybridization on Drosophila melanogaster embryos. You apply a probe labeled with a fluorescent stain that is complementary to mRNA transcripts of the gene hunchback. In early stages of embryogenesis you observe fluorescence for the entire half of the embryo only. In embryos at a later stage of development you see that same pattern in the anterior, and also a stripe of fluorescence in the posterior half. What can you conclude about the expression of hunchback from this? hunchback is first expressed in the anterior of the embryo and later in a portion of the posterior In which example are the proximate cause and the ultimate cause of morphological evolution correctly matched? proximate: changes in gene regulation lead to changes in morphology; ultimate: natural selection favors morphologies that work best in their environment A famous example of allometry, the antlers of the extinct Irish elk (megaceros giganteus) ... were larger, relative to body mass, than those of any other deer Which would place the greatest constraint on evolvability in a population experiencing directional selection? lack of co-variation in structures that depend on close match to each other