Epilogue

1
Epilogue

• A few years later, 1359mm of rain fell on the
  island
• 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 dont know.

4
Epilogue continued

• The cycles werent 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.
• Lets 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. 707711.
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 didnt 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 didnt 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 didnt change.
• D They are a little more blunt.
• E They are a lot more blunt.