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Natural Selection and the Rock Pocket Mouse — HHMI BioInteractive Video
Background: In the “Valley of Fire” in New Mexico lives the Rock Pocket mouse. This little mouse comes in two main
varieties, light fur and dark fur. It weighs just 15 grams and measures about 17 cm from nose to rump. Most of the
desert landscape is covered by light sand and granite. Here and there, however, separated by several kilometers, are
patches of dark basaltic lava flows. The dark volcanic rocks range in age from 1,000 to more than 1 million years old.
Dr. Michael Nachman from the University of Arizona has spent many years researching the genetics of fur color in the
rock pocket mice. In particular, they are interested in understanding the forces that shape genetic variation in natural
populations. This video is a summary of their work and their findings.
Part 1: As you watch the video answer the following questions.
1. What specific trait did the researchers study in this investigation?
2. How does this trait affect the survival of the mice in different environments?
3. Is this trait controlled by one or many genes?
4. What is the genetic basis of the trait?
5. How long would it take this trait to spread to most of the population if there was a:
a. 1% advantage to survival?
b. 10% advantage to survival?
6. Is mutation a random process?
7. Is evolution a random process?
8. Are there any other populations of rock pocket mice that show the same shift in the population?
9. How does this study support Darwin’s theory of evolution by natural selection?