Cambridge Secondary (7-9). Stage 9. MCE Science. Workbook - Unit 3: Variation and Inheritance - Question 43

A study was conducted on the seed-eating finch population on the Galápagos Islands. It was observed that when rain was plentiful, the plants produced many small, soft seeds. During periods of drought, only a few small, soft seeds were produced. These were usually eaten by other animals before the finches could get to them. The seeds that remained were large, dry and hard.

Study the graphs. Describe how the finch population with different beak sizes changed before and after the drought period.