University of Washington, Seattle

BIOLOGY 180

RQ11-Patterns

1)Consider the data on cliff swallow mortality. Why is this an example of directional selection?

2. What is stable during stabilizing selection?
3. When stabilizing selection occurs, which of the following is NOT true?

RQ12-Misconceptions

1. If the skin of a Caucasian person darkens in response to exposure to sunlight, what has happened?
2. The text claims that when natural selection occurs, the characteristics of the selected individuals do not change--only the characteristics of the population change. Why is this so?
3. Can natural selection occur in a population that is declining, and possibly going extinct?
4. Is it wrong to claim that a trait evolved so the species involved can survive better?
5. What is a fitness trade-off?
6. What is a “cheater allele?”
7. Why isn’t evolution by natural selection progressive?
8. Why aren’t adaptations perfect? (for example, why do backs, eyes, knees, and

other structures in humans cause so many problems?)