Beak of the finch

Which is the most likely explanation for the presence of 13 different finch species on the Galápagos Islands today?

• Many years ago, several different species of birds migrated to the islands and the 13 finch species that currently live there are the only species that survived.

• Many years ago, a small population of a single bird species migrated to the islands and evolved into the 13 species that live on the islands today.

• Each of the 13 species has migrated to the islands at different times over the years.

• A single bird species migrated to one island at around the time of Charles Darwin’s voyage to the Galápagos and then migrated to all 13 islands.

Different finch species have beaks of different shapes and sizes. These different beak structures are evidence of:

• different finch species adapting to different environments over many generations.

• different finch species with different beak structures coming to the Galápagos Islands from the mainland.

• different finch populations being evolutionarily related.

• individual birds changing their beak characteristics so that they could feed efficiently.

Examine the phylogenetic tree of the 13 finch species. Which of the following statements is a correct interpretation of the phylogenetic tree in the illustration?

• The sharp-beaked ground finch is more closely related to the small tree finch than either species is to the cactus finch.

• The warbler finch is the common ancestor to all the finch species that exist today in the Galápagos Islands.

• All the Galápagos finches are more closely related to one another than they are to mainland finch species.

• The 13 finch species evolved in sequence; the warbler finch is the oldest species and the small ground finch is the most recent species to evolve

Which of the five statements below describe(s) geographically isolated populations? Select the appropriate answer.

i. The two populations live on different islands.

ii. One population breeds in late spring and the other population breeds in late summer.

iii. One population eats mostly small, soft seeds and the other population eats mostly large, hard seeds.

iv. The males of one population have different mating calls than the males of the other population.

v. The females of the two populations look the same.

• statement i only

• statements i and iv only

• statements ii, iii, and v only

• statement iv only

Which of the five observations below provide(s) evidence that two populations are likely experiencing reproductive isolation and that there is little if any genetic exchange between them?

i. The two populations live on different islands.

ii. One population breeds in late spring and the other population breeds in late summer.

iii. One population eats mostly small, soft seeds and the other population eats mostly large, hard seeds.

iv. The males of one population sing different songs than the males of the other population.

v. The females of the two populations look the same.

• statement i only

• statements iii and v only

• statements i, ii, and iv only

• statements ii and iv only