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Study Questions for Genetics, Natural Selection and Sexual Selection

1. After an artificial selection experiment on the frequency of wingbeats during the courting rituals in flies, you reach an upper plateau (graph?). Give two reasons why wingbeat frequency might not be able to continue increasing.


2. Two biologists observe male fighting behavior in red deer. One biologist suggests the reason for fighting is that dominant males control more females and have higher fitness. The other insists they fight because a seasonal increase in testosterone causes aggressiveness. Who is right? (a real thinker pulling in much of the material from lecture 1 -- proximate and ultimate causes, and lecture 3 -- selection, and even a bit on 2 -- genes).


3. Name and explain three primary ways selection effects the differential fitness of individuals. Draw graphs to represent the changes each mode of selection would be expected to cause in the mean and variance of a population.


4. How does selection on stripped vs spotted snakes, and selection on reversing vs non-reversing escape tactics yield only two kinds of snakes:

  1. stripped -- non-reversing snakes and
  2. spotted -- reversing snakes?

Assume one gene controls color, and another controls behavior. Assume that the gene that controls color has two alleles (stripped and spotted) and the gene that controls behavior has two alleles (non-reversing and reversing) shouldn't we see at least four kinds?


5. Compare and constrast natural selection and sexual selection. Is there a distinction between the two that is important?


6. In the runaway process of sexual selection, what trait is under selection in the males and what trait is under selection in the females. Which male traits are favored, and which female traits are favored? Why is runaway selection an example of maladaptive evolution?


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