In the phylogeny shown, which of the following hypotheses provides the most parsimonious explanation for the distribution of beak ("bill") color among the five species of magpie? The yellow-billed magpie has a yellow beak and the rest have black beaks.
A) There is no way to infer ancestral beak color using the phylogenies shown.
B) The ancestral state was yellow-billed.
C) The ancestral state was black-billed.
D) The ancestral state was most likely neither yellow nor black but rather some intermediate color of beak.

Question

In the phylogeny shown, which of the following hypotheses provides the most parsimonious explanation for the distribution of beak ("bill") color among the five species of magpie? The yellow-billed magpie has a yellow beak and the rest have black beaks. 
A) There is no way to infer ancestral beak color using the phylogenies shown. 
B) The ancestral state was yellow-billed. 
C) The ancestral state was black-billed. 
D) The ancestral state was most likely neither yellow nor black but rather some intermediate color of beak.

Quizplus · Accepted Answer

Based on the phylogeny shown, the most parsimonious explanation for the distribution of beak color among the five species of magpie is that the ancestral state was black-billed. This is because only one species (yellow-billed magpie) has a yellow beak, while the rest have a black beak. The simplest explanation for this is that the ancestral state was black-billed, and that the yellow-billed magpie evolved a yellow beak independently. Option A is incorrect because it is possible to infer ancestral states from a phylogeny. Option B suggests that the yellow-billed magpie is the ancestral species, which is not supported by the phylogeny. Option D suggests an intermediate color of the beak as a possible ancestral state, but there is no evidence to support this hypothesis.

In the Phylogeny Shown, Which of the Following Hypotheses Provides