1. Epilogue A few years later, 1359mm of rain fell on the Islands:
The finches went crazy — the finch population increased by 400%!
Lisle Gibbs, a graduate student of the Grants, was there and she measured every finch carefully.

2. Epilogue continued…
When Gibbs returned to Princeton and analyzed his data, he was stunned:
Natural selection had reversed course.
Large finches were dying:
Small seeds were everywhere, but it took too many of them to satiate a large finch with a beak built for big seeds.
Small finches were reproducing like crazy.

3. CQ10: If small birds are selected against in one year and selected for in another, is evolution still taking place?
A: Yes.
B: No.
C: Maybe.
D: I don’t know.

4. Epilogue continued… The cycles weren’t over yet:
A year after the heavy rains, 53mm of rain fell.
The year after that, the grand total: 4mm.
Galapagos weather patterns are cyclical.
Let’s look at the finches over a longer time scale…

5. The graphs on this and the following slides are details from Figure 1 in "Unpredictable Evolution in a 30-Year Study of Darwin's Finches” by Peter R. Grant and B. Rosemary Grant, Science, 26 April 2002, vol. 296, no. 5568, pp. 707–711. Used with permission from AAAS.

6. CQ11: How has the average body size of these finches changed 1973-2001?
A: They are much larger.
B: They are a little larger.
C: They didn’t change.
D: They are a little smaller.
E: They are a lot smaller.

7. CQ12: How has the average beak size of these finches changed?
A: They are much larger.
B: They are a little larger.
C: They didn’t change.
D: They are a little smaller.
E: They are a lot smaller.

8. CQ13: How has the beak shape changed?
A: They are a lot more pointed.
B: They are a little more pointed.
C: They didn’t change.
D: They are a little more blunt.
E: They are a lot more blunt.