PRACTISE QUESTIONS BIOL 1001 W2012 Key
17. Some biologists encapsulate evolution by natural selection with the phrase “mutation proposes, selection disposes”.
Explain what they mean, using the formal terms you have learned to describe evolutionary processes.
18. Of all the mutations that occur in a population, why do only a small fraction become widespread among the
19. In 1986 a nuclear power accident in Chernobyl, USSR (now Ukraine) led to high radiation levels for miles
surrounding the plant. The high levels of radiation caused elevated mutation rates in the surviving organisms, and
evolutionary biologists have been studying rodent populations in the Chernobyl area ever since. Based on your
understanding of evolutionary mechanisms, which of the following most likely occurred in the rodent populations
following the accident?
20. Why are mutations important in evolution, when most mutations are harmful?
21. Natural selection can only act on traits: