There are two competing hypotheses about how the distribution of the three close
ID: 177827 • Letter: T
Question
There are two competing hypotheses about how the distribution of the three closely related species pictured to the left came about. One is a yicariance hypothesis in which there was a single ancestral species that occupied the entire range before the formation of the mountains or the river. First the mountain range formed, separating the western population from the eastern population. Later, the river formed, separating the northeastern population from the southeastern population. The second hypothesis is a dispersal hypothesis in which the population occurs initially on the west side of the mountain range. In the first dispersal event, part of the population migrates over the northern part of the mountains to form the northeastern population. Later, individuals from the northeastern population disperse over the river to form the southeastern population. The following two questions relate to these competing hypotheses. 4. Which of the following cladograms depicts the evolutionary relationships that would result from the yisarianse hypothesis?Explanation / Answer
4. Option B is the correct answer.
5. No, B and C are closest relatives in both scenarios.