Question

date
this handout supplements the short film the origin of species: the beak of the finch.

1. which is the most likely explanation for the presence of 13 different finch species on the galápagos islands today?

a. 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.
b. 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.
c. each of the 13 species has migrated to the islands at different times over the years.
d. a single bird species migrated to one island at around the time of charles darwins voyage to the galápagos and then migrated to all 13 islands.

1. different finch species have beaks of different shapes and sizes. these different beak structures are evidence of

a. different finch species adapting to different environments over many generations.
b. different finch species with different beak structures coming to the galápagos islands from the mainland.
c. different finch populations being evolutionarily related.
d. individual birds changing their beak characteristics so that they could feed efficiently.

1. examine the phylogenetic tree of the 13 finch species below. which of the following statements is a correct interpretation of the phylogenetic tree in the illustration?

a. the sharp - beaked ground finch is more closely related to the small tree finch than either species is to the cactus finch.
b. the warbler finch is the common ancestor to all the finch species that exist today in the galápagos islands.
c. all the galápagos finches are more closely related to one another than they are to mainland finch species.
d. 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

Explanation:

1. Question 1:

• According to the theory of evolution and the concept of adaptive radiation, a single ancestral species can give rise to multiple species through evolution. In the case of the Galápagos finches, it is believed that a small population of a single bird species migrated to the islands and then evolved into the 13 species we see today. Option a is incorrect because it implies multiple starting species, option c is not in line with the idea of a common - ancestor - based evolution, and option d is too simplistic as the evolution was a long - term process, not just related to Darwin's voyage.

1. Question 2:

• The different beak structures of finch species are a result of natural selection. Different environments on the Galápagos Islands favored different beak shapes and sizes for feeding. Option b is incorrect as the beak differences are due to evolution on the islands, not just migration. Option c is a more general statement that does not directly explain the beak differences as evidence. Option d is wrong because it is populations that evolve over generations, not individual birds changing their beaks.

1. Question 3:

• In a phylogenetic tree, the closer the branches, the more closely related the species. The Galápagos finches share a more recent common ancestor among themselves compared to the mainland finch. Option a: The sharp - beaked ground finch and small tree finch do not have a closer relationship than with the cactus finch as per the tree. Option b: The warbler finch is not the common ancestor of all Galápagos finches. Option d: The 13 species did not evolve in a simple linear sequence as depicted in the tree.

Answer:

1. b
2. a
3. c