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Life, 4/e

Ricki Lewis, University of New York at Albany
Mariëlle Hoefnagels, University of Oklahoma
Douglas Gaffin, University of Oklahoma
Bruce Parker, Utah Valley State College

The Forces of Evolutionary Change--Microevolution

Testing Your Knowledge

1. Define the following:

a. population

b. gene pool

c. gene flow

d. genetic load

e. genetic drift

2. Explain how the algebraic expression p2 + 2pq = q2 is used to represent genotypes.

3. The fraggles are a population of mythical, mouselike creatures that live in underground tunnels and chambers beneath a large vegetable garden that supplies their food. Of the 100 fraggles in this population, 84 have green fur and 16 have gray fur. A dominant allele F confers green fur and a recessive allele f confers gray fur. Assuming Hardy-Weinberg equilibrium is operating, answer the following questions:

a. What is the frequency of the gray allele f?

b. What is the frequency of the green allele F?

c. How many fraggles are heterozygotes (Ff)?

d. How many fraggles are homozygous recessive (ff)?

e. How many fraggles are homozygous dominant (FF)?

4. One spring, a dust storm blankets the usually green garden of the fraggles in gray. Under these conditions, the green fraggles become very visible to the Gorgs, who tend the gardens and try to kill the fraggles to protect their crops. The gray fraggles, however, blend into the dusty background and find that they can easily steal radishes from the garden. How might this event affect microevolution in this population of fraggles?

5. What are two reasons that deleterious recessive alleles persist in populations, even though they prevent individuals from reproducing when present in two copies?

6. Distinguish among directional, disruptive, and stabilizing selection.

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1. Explain an experiment discussed in this chapter or elsewhere in this unit that demonstrates that evolution is occurring.

2. For the following glimpses of populations at two points in time, state whether microevolution is occurring. If so, how it is occurring, and make up a scenario to explain what is happening. ta1501 (417.0K)

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15.1 Why Is Evolution Much More Likely Than Not?

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15.2 How Does Mate Choice Influence Evolution?

15.3 How Does Mutation Fuel Evolution?

15.4 How Does Natural Selection Mold Evolution?

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