Study Questions - Speciation
Readings - chapter 19
1) Defend the use of an ecological species concept.
2) Usually we think of selection as creating differences BETWEEN populations and gene flow as maintaining SIMILARITY between populations. How can seelction maintain vairation within populations, and how can selection create similarity between populations?
3) How would you use Nei's genetic distance to define species?
4) What are the caveats to this approach?
5) What is the genetic distance between these two populations:
| LOCUS 1 | LOCUS 2 | |||
| p | q | p | q | |
| POP1 | 0.7 | 0.3 | 0.1 | 0.9 |
| POP2 | 0.4 | 0.6 | 0.8 | 0.2 |
6) Describe the evidence in Drosophila suggesting that the degree of reproductive isolation increases continuously as genetic distance increases.
7) Inversions have both negative and potentially beneficial effects. List one of each. If an inversion is selected for and increases in frequency, why does the deleterious consequences for fertility of the population decline?
8) Describe the evidence from D. pseudoobscura that inversions stabilize adaptive gene complexes.
9) Translocations can become stabilized in populations, reinforcing reproductive isolation between resulting species. Explain, using a real example.
10) List 5 pre-zygotic reproductive isolating mechanisms and give an example for each.
11) List four post-zygotic isolating mechanisms and give an example of each.