Chapter 5 questions
1. What has to happen for evolution via natural selection to occur?
1b. When we say that natural selection 'acts on something' what do we really mean?
2. Why do we say that mutations are random?
3. In what sense are mutations not random?
4. Is evolution via natural selection random?
7. MISCONCEPTION: Natural selection involves organisms trying to adapt. What's
the correction for this?
5. Coyne puts up some pretty big demands on natural selection.
What are they?
5b. Why is it important that biologists haven't found a single adaptation whose
evolution absolutely requires an intermediate step that reduces the fitness of
individuals?
6. MISCONCEPTION: Natural selection acts for the good of the species. What's the
correction for this?
8. What is genetic drift? How does drift compare to natural selection?
9. In what ways are artificial selection (i.e. domestication of dogs, breeding of crops
for particular traits) alike?
In what ways are they different?
10. What are the lessons to be had from humans selecting on dogs, corn, wheat, rice,
cows, etc.?
11. Coyne describes selection experiments done in E. coli by Rich Lenski. Over the
course of 18 years (40,000 generations), E. coli have evolved to grow 70% faster
than the original unselected strain. Is this rapid evolution? As a though experiment,
how long would it take humans to go through 40,000 generations assuming a
generation time of 20 years?
12. Coyne describes evolution in bacteria, HIV/AIDS, insects as a function of DDT,
etc. What is the point here?
13. What are some of the examples Coyne gives of natural selection in nature?
Explain how these studies show (a) variation in traits, (b) heritability, and (c) a
relationship between trait value and fitness.
14. Coyne argues that for complex traits - like the bacterial flagellum or biochemical
pathways - we need not be able to identify each step in the process. Instead, we
need to know that the constituents of the pathway were based on some other precursor. Do you find this compelling?
15. What evidence do they provide that the blood clotting mechanisms evolved
from proteins involved in other functions?
16. Eyes are frequently touted as a complex trait that would be hard to evolve.
What evidence does Coyne discuss to rebut this claim?