Question

How did bird beak depth change in drought conditions in the Rainfall and Bird Beaks gizmos? Select the most appropriate response:

a) No change.
b) Beak depths decreased because the birds had access to small, delicate seeds.
c) Beak depths increased because the only surviving birds had larger beaks capable of cracking hard seeds.

Answer 1

Bird beak depth increased during drought conditions, as finches with larger beaks could feed on available hard seeds and were more likely to survive and reproduce, leading to evolution through natural selection.

Step-by-step explanation:

The correct response to how bird beak depth changed during drought conditions in the Rainfall and Bird Beaks gizmos is that beak depths increased, as the only surviving birds had larger beaks capable of cracking hard seeds. During a drought on the Galápagos, the Grants observed a reduction in small seeds, leading to the death of many small-beaked finches.

This demonstrated that finches with larger beaks were more suited to the environment as they could feed on the available large, hard seeds. Natural selection favored these birds, allowing them to survive and reproduce, thereby passing on their traits to future generations. As conditions persisted, the finch population evolved to have a greater percentage of birds with these advantageous larger beaks.