Chapter 13: Darwinian Medicine

1.	Pathogen populations evolve quickly because they have _____ population sizes, _____ generation times, and _____ mutation rates. [Hint]
2.	Fitch et al. hypothesized that influenza strains with novel antigenic sites would enjoy a selective advantage over strains with mutations in non-antigenic sites. The graphs represent data gathered as they tested this hypothesis. Graph A shows the degree of nucleotide divergence in hemagglutinin genes from samples of influenza virus collected from the mid-1960's to 1987. Graph B is a phylogenetic tree showing the pattern of descent in the various lineages. You may refer to Figure 13.4 in your textbook for more detailed graphs. Which of the following is/are reasonable interpretations of these results? [Hint]
3.	Which of the following support(s) Fitch et al.'s hypothesis that influenza strains with novel antigenic sites enjoy a selective advantage over strains with mutations in non-antigenic sites? [Hint]
4.	The global influenza pandemic of 1968 likely occurred because a human influenza strain acquired the hemagglutinin gene H3 from an avian influenza strain. Which of the following pieces of evidence support(s) the hypothesis that the acquisition happened after an avian and swine strain simultaneously infected a pig and swapped genes, creating a new strain that was then transmitted to humans? [Hint]
5.	Briefly describe one line of evidence in favor of the hypothesis that the use of antibiotics selects for resistance in bacteria. [Hint] To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
6.	The graph below illustrates changes in resistance of Pneumococcus bacteria in children in Iceland to penicillin. The use of penicillin was strongly discouraged starting in the early 1990's with the results illustrated. According to Schrag et al.'s studies on the cost of resistance, is the trend shown on the graph guaranteed to continue? Briefly explain why or why not. [Hint] To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
7.	Three hypotheses have been proposed to explain the evolution of virulence. Match each of the examples below to the hypothesis it best represents. [Hint] Using the pulldown boxes, match each item on the left to the corresponding item at right. A. coincidental evolution hypothesis B. trade-off hypothesis C. short-sighted evolution hypothesis Choice A Choice B Choice C Late strains of HIV virus are more virulent than early strains within the same host.  [Hint] Choice A Choice B Choice C Histoplasmosus capsulatum is a fungus found naturally in soils and in areas contaminated with bird and bat droppings. Most people living in areas where the fungus is endemic have contracted it through airborne spores and, after a brief period of flu-like illness (called histoplasmosis), become immune to it. However, some people develop severe lung infections; in some patients, the infection can spread to other organs. These infections can be fatal if not treated. Histoplasmosis is not transmitted from person to person.  [Hint] Choice A Choice B Choice C Plasmids of E. coli selected for horizontal transmission show lower virulence and slower reproduction than do plasmids selected for vertical transmission.  [Hint]
8.	According to Ewald's analysis of the trade-off hypothesis for virulence, which of the following pathogens should be the least virulent? [Hint]
9.	Twin studies suggest that myopia is heritable. When Young et al. compared Eskimo children receiving American-style educations and doing a lot of reading with their parents who spent much less time in formal classroom schooling, they found that the incidence of myopia in the children was much higher than in the parents. Together, these observations support what hypothesis for the presence of myopia in modern humans? [Hint]
10.	Which of the following correctly characterize(s) the evidence for or against a role for viruses in human breast cancer? [Hint]
11.	Which of the following support(s) the hypothesis that breast cancer is a maladaptive consequence of life in a novel environment (specifically, one in which women experience more menstrual cycling). [Hint]
12.	Briefly describe two lines of evidence suggesting that behavioral fever in ectotherms is an adaptive response to infection. [Hint] To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
13.	Based on Banet's experimental work with rats, which of the following correctly characterize(s) the effects of fever in endotherms? [Hint]
14.	Refer to Figure 13.21 in your textbook. The graphs in the figure present the results of Graham et al.'s study of the effects of anti-fever medications on the common cold. Which of the following explain(s) these data? [Hint]
15.	The textbook authors present a number of cases indicating that stepchildren suffer in a variety of ways from lowered parental care relative to genetic children. Which of the following correctly identifies what evolutionary psychologists Daly and Wilson believe is adaptive about this pattern? [Hint]
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