I typically include 10-12 questions on an examination, asking students to answer 8-10.  In some cases there will be choices of questions on a particular topic or chapter.  All of the questions can be answered by a few well-chosen sentences.

Exam 1
Exam 2
Exam 3

1. What do you need to know about similar structures in order to decide if they are analogous or homologous?
2. Charles Darwin had a copy of Lyell’s geology text book with him on the voyage of the Beagle. Lyell was a champion of the uniformitarian view. How did Lyell’s view of geological change influence Darwin’s view of biological change?
3. Explain why a "blending" mechanism of heredity would be inconsistent with natural selection.
4. Many environmental stresses (chemicals, radiation, heat) can increase mutation rate. If global warming causes hotter climates, is it likely that the heat will induce mutations which enable organisms to survive the heat?
5. Our text claims that a high mutation rate helps HIV adapt to a diverse immunological environment. If this is true, would you expect natural selection to continue to amplify the mutation rate?
6. In lecture I said that evolution creates new things by recycling old things. Give two examples of this principle: one at the organ level of organization, and one at the molecular level of organization.
7. Explain briefly how gene duplication resulting from unequal crossing over can result in the production of novel proteins. Provide a diagram.
8. Mistakes of DNA replication which produce point mutations can occur wherever in the organism cells are dividing. Are all of these mutations passed on to offspring? Your answer should address plants as well as animals.
9. Explain why a pattern of strong parent-offspring correlation in a trait is not always sufficient to show that the trait is heritable. Your answer should include an example.
10. Our text provides information on mutation rates. Vote for one of the following statements and defend your choice: (a) the published rates probably over-estimate the true rates, (b) the published rates probably under-estimate the true rates, (c) the published rates are right on.
11. Dr. Sosmart has determined that 90% of the oak seedlings this year have sprouted from acorns produced by 10% of the trees last year. Does this strong example of differential reproduction prove that natural selection is operating in the oak population?
12. Define "fitness", in the evolutionary sense.
13. Natural selection can cause species to adapt to challenges in the biotic or physical environment. HIV/AIDS certainly counts as a challenge to our species, but what conditions would have to be met for humans to evolve increased resistance to HIV? Hint -- refer to Darwin's postulates.
14. Under the Ewald transmission rate hypothesis for the evolution of virulence in HIV, why would we expect high virulence strains to decrease in frequency if sexual partner exchange is infrequent?
15. Figure 1.12 in our text shows that the pattern of immunodeficiency virus (SIV, HIV, etc.) evolution does not correspond to the pattern of primate host evolution. If it did, how might the presence of HIV in the human population be explained?
16. What do you need to know about similar structures in order to decide if they are analogous or homologous?
17. Explain why mutation rates based on recording loss-of-function mutations tend to underestimate the genome-wide mutation rate.
18. Many environmental stresses (e.g., chemicals, radiation, heat) can increase mutation rate. If global warming results in hotter climates, is it likely that the heat stress will induce specific mutations which enable organisms to survive the heat?
19. What kinds of mutations are required to create new genes?
20. Why does polyploidization in plant populations result in the formation of new species literally overnight?
21. Mistakes of DNA replication which produce point mutations can occur wherever in the organism cells are dividing. Are all of these mutations passed on to offspring? Your answer should address plants as well as animals.
22. Explain why a pattern of strong parent-offspring correlation in a trait is not always sufficient to show that the trait is heritable. Your answer should include an example.
23. After the publication of the Origin of Species in 1859, many problems with Darwin's theory of evolution by natural selection were raised in the scientific community. Cite one of these problems and indicate briefly how the problem has been resolved.

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1. Suppose you observe a new trait spreading rapidly in a population. Which is the more likely explanation for its spread: repeated mutations or natural selection? Explain
2. Here is a copy of Figure 5.12. Explain why the frequency of sinistral (left-handed) fish is always close to 50%.
3. Using the expression for the Hardy-Weinberg equilibrium, show why rare alleles are mostly in the heterozygous condition, and not the homozygous condition.
4. True or false - Genetic drift only occurs in small populations. Explain your answer.
5. Consider two species of plants. One has wind-dispersed seeds, the other has squirrel-dispersed seeds. In which species would you expect to find more among-population variation in allele frequency? Explain.  Note - assume that wind-dispersal is more effective than dispersal by squirrels.  "Among-population variation" means differences among population, not within populations.
6. Figure 5.31 shows the pattern of pollen and seed dispersal in the angiosperm Lupinus texensis. Explain how the two graphs taken together suggest that inbreeding is occurring in that species.
7. Let = the equilibrium frequency of a mutant allele, = the rate at which mutation creates new copies of the allele, and s = the intensity of selection against the allele. It turns out that =. Explain what this equation means.
8. We read about the water snakes of Lake Erie. On the islands in western Lake Erie most of the snakes are unbanded, while on the mainland, many snakes are banded. Predict what would happen to relative frequencies of unbanded and banded snakes on the islands if plate tectonics moved the islands farther away from the mainland. Explain.
9. Why are sex ratios in many populations 50/50, male/female?
10. True or false – evolution cannot occur in a clone of asexually reproducing organisms, because in the absence of sexual reproduction, there is no variation for natural selection to work with. Justify your answer.
11. In theory, inbreeding should be a serious problem in captive zoo populations. Yet in many cases, it is difficult to detect inbreeding depression in well-maintained captive populations. Why might this be?
12. Our textbook authors say that mutation by itself generally not a "potent evolutionary force ".  What do they mean by this?  And why do they spend so much time talking about mutation if it isn't a potent evolutionary force?
13. Early in the semester I used the polar bear as an example to illustrate natural selection.  I suggested that white polar bears evolved from their brown ancestors because of the camouflage advantage of white fur.  What is the problem with this story?
14. We read about the water snakes of Lake Erie.  On the islands in western Lake Erie most of the snakes are unbanded, while on the mainland, many snakes are banded. Predict what would happen to the snakes if plate tectonics moved the islands farther away from the mainland.  Explain.
15. Why is inbreeding depression in plants easier to detect in wild populations than in the greenhouse or experimental garden?
16. Why do islands distant from the mainland have so many endemic species? Provide two reasons.
17. Redwood trees can reach stupendous heights.  Why aren't they yet taller?  Why aren't they shorter?  This question asks you to indicate the selective forces which act on tree height.
18. Individuals of  Fuchsia excorticata have a trait which is apparently maladaptive:  they maintain flowers on the plant after they lose the ability to produce or receive pollen. Fitness would be increased by dropping the flowers soon after they cease to be functional.  Why hasn't natural selection fixed this glitch?
19. Explain why the ability of Brachionus calyciflorus and Daphnia magna to reproduce asexually makes these species ideal organisms for studying phenotypic plasticity.
20. What is the ultimate outcome of directional selection on allele frequencies?

In the example of the left-handed and right-handed fish, feeding success depends very much on whether a fish is left-handed or right-handed.  So why doesn't one form replace the other?

1. It makes sense that the function of sex is reproduction. But is this right?
2. Explain why in the model called "Muller’s ratchet", the mean number of deleterious mutations per individual increases as time goes by.
3. How would you test the hypothesis that host-parasite coevolution favors the maintenance of sexual reproduction?
4. Early in the semester I used the polar bear as an example to illustrate natural selection. I suggested that white polar bears evolved from their brown ancestors because of the camouflage advantage of white fur. Evaluate this scenario.
5. Why are C4 plants favored in hot, dry environments?
6. What is the difference between phenotypic plasticity and adaptation?
7. Give an example of a situation where a "trade-off" limits adaptation.
8. Is geographical isolation necessary for speciation?
9. Under what circumstances is prezygotic reproductive isolation likely to occur?
10. The first step in allopatric speciation involves geographical isolation.  Explain, citing examples,  how does geographical isolation occurs.
11. Under what circumstances is prezygotic reproductive isolation likely to occur?
12. Is it likely that the present “races” of Homo sapiens will diverge into separate species in the future?
13. The Rift Lakes of East Africa are exceptionally rich in species of  Cichlid fish. Sediment analysis indicates that these lakes have experienced severe fluctuations in water level. Explain how this can account in part for their high species diversity.
14. Explain why morphological discontinuities between populations classified into separate morphological species suggest that the populations might also be separable under the biological species concept.
15. Of all the genes in existence, why choose the gene for small-unit rRNA to construct a phylogeny of  life?
16. Explain how the rRNA phylogeny supports the endosymbiotic theory of the origin of mitochondria and chloroplasts.
17. When did the cenancestor live?  How do we know?
18. What is implied by the claim that hemoglobin, myoglobin and leghemoglobin are homologous, despite having very different functions?
19. Which should evolve faster, a gene or a pseudogene derived from the same gene?
20. According to text Table 7.2  the gene for growth hormone has a much higher rate of nucleotide substitution than the gene for histone 3.  How can this be explained?
21. Provide approximate dates for the following: the common ancestor of chimpanzees and humans, the origin of the genus Homo, the origin of anatomically modern Homo sapiens.
22. Cite two pieces of evidence in support of the multiregional evolution model for the evolution of anatomically modern Homo sapiens.
23. Cite two pieces of evidence in support of the single origin model for the evolution of anatomically modern Homo sapiens.
24. Briefly explain the "social complexity" theory for the evolution of increased intelligence in humans.
25. Explain how reduced resource density during the Miocene-Pliocene may have led to evolution of smaller group size in chimpanzee ancestors and bipedal locomotion in human ancestors.