The exam will be Thursday, March 24. and will be worth 30 percent of your grade for the course. If you will be absent that day, e-mail me by the end of the day on Friday, March 18, so that we can schedule your makeup exam.
You may not use your notes during the exam. You will not need a calculator.
The exam will consist of 20 questions. Each of your answers should consist of one to a few sentences. You may include drawings in your answers if they help you make your point. While there is no strict length limit, you may get points off for writing long, rambling answers that say the same thing over and over.
Here are some practice questions. Try answering them, then highlight the invisible text inside the red box (drag your cursor across it) to see my answer.
1. Based on their similar size, short tails, and cute noses, you think that guinea pigs and rabbits are more closely related to each other than they are to rats and mice. How would you test this hypothesis? What result would be consistent with your hypothesis?
2. Rodents make the enzyme L-gulonolactone oxidase, which they use to synthesize vitamin C; primates do not make this protein, and therefore have to get vitamin C from their diet rather than synthesizing it. How would you determine whether the common ancestor of rodents and primates was able to synthesize vitamin C? Give all the possible results of your experiment and how you would interpret each one.
3. You've decided to write your term paper about ammonites. What are the three most important things you would do to find scientific literature about ammonites?
4. The spadefoot toad, Scaphiopus couchii, lives in southern New Mexico. Some toads live on dark rock and are dark colored; some live on white sand and are light colored. You want to know whether this difference in color is genetic. You don’t know whether any genes are involved, much less which genes. What experiment could you do to tell whether the difference in color between populations of toads from dark rock vs. white sand is genetic? What would the result be if the difference is not genetic?
5. Berry et al. (1991) measured DNA sequence polymorphism on the fourth chromosome of two species of Drosophila and found that the fourth chromosome had much less polymorphism than other chromosomes. What is this evidence of? Why?
6. Some people have wet, sticky earwax; other people have dry, crumbly earwax. This is caused by variation at a single gene with two alleles; the allele for wet earwax (W) is dominant over the dry allele (d). Right now, the frequency of W is about 90% in the United States. What do you expect to happen to the frequency of W in the United States over the next 100 years? Why?
7. Flies in the species Drosophila heteroneura have their eyes on the end of long stalks. Some individuals have longer stalks than others. Without using any kind of DNA data, what kind of experiments would you do to tell whether this variation in stalk length within a population is genetic? What result would you get if the variation is mostly genetic?
8. You've convinced yourself that the variation in stalk length in question 7 is mostly genetic. You've done careful observations and shown that there's no difference in survival between long and short-stalked flies. Since you're interested in finding out whether there's selection on stalk length, what other kind of experiment should you do? Why?
9. Janet Weiss of Denton University is studying a genetic polymorphism in cats, the long hair locus. Cats with the dominant L allele have short hair, while cats that are homozygous for the recessive l allele have long hair. She observes the hair length (long or short) on 100 cats from Hockessin, Delaware and estimates the allele frequency of l is 0.60. How did she do that? (You don’t have to do the calculations, just describe how the basic principle she used works.)
10. Kärkkäinen et al (2004) found that plants in one area of Finland had a high frequency of trichomes, while plants in other areas had a low frequency of trichomes. What additional evidence did they collect and how did it show evidence that natural selection affected the trichome gene?
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This page was last revised March 2, 2016. Its URL is http://udel.edu/~mcdonald/evolstudyguide.html