PROBLEM: How does the depth of finch beaks vary with drought or heavy rain?

How did the beak depth change over time?

ANALYSIS:

ACTIVITY B (Drought):

• How did the number of finches change after the five years of drought? Why do you think this happened? (2 marks)
• What happened to the average beak depth after the five years of drought? Why do you think this happened? (2 marks)

• Directional selection occurs when individuals at one end of a range are more likely to survive than intermediate individuals or individuals at the opposite end of the range. Stabilizing selection occurs when intermediate individuals are the most likely to survive.

Is directional selection, stabilizing selection, or both operating in this example? Explain.        (2 marks)

• Evolution is the process by which populations of organisms can change over time. How is directional selection related to evolution? (2marks)

ACTIVITY C (Rainy Days):

• How did the number of finches change after the five years of rain? Why do you think this happened? (2 marks)
• What happened to the average beak depth after the five years of rain? Why do you think this happened? (2 marks)

• Most scientists think that a small group of finches colonized the Galápagos Islands thousands of years ago. They would have been the only seed-eating birds on the islands. Suppose one island was very dry and another had plentiful rainfall. 

• How would the finch populations on these islands change over time? (2 marks)

• What might happen to the finch populations after millions of years? (2 marks)

CONCLUSION:

 What can you conclude about the answer to the problem (how does the depth of finch beaks vary with drought or heavy rain?) (2 marks)