The following questions refer to the paragraph and graphs below.
In a hypothetical situation, the National Park Service, which administers Grand Canyon National Park in Arizona, builds a footbridge over the Colorado River at the bottom of the canyon. The footbridge permits interspersal of two closely related antelope squirrels. Previously, one type of squirrel had been restricted to the terrain south of the river, and the other type had been restricted to terrain on the north side of the river. Immediately before and ten years after the bridge's completion, ten antelope squirrels from both sides of the river were collected, blood samples were taken, and frequencies of alleles unique to the two types of antelope squirrels were determined (see graphs below).

-Upon undergoing change, which of these genes is most likely to result in speciation while a geographic barrier separates two populations of a flowering-plant species?
A)one that affects the rate of chlorophyll a synthesis
B)one that affects the amount of growth hormone synthesized per unit time
C)one that affects the compatibility of male pollen and female reproductive parts
D)one that affects the average depth to which roots grow down through the soil
E)one that affects how flexible the stems are

Question

The following questions refer to the paragraph and graphs below.
In a hypothetical situation, the National Park Service, which administers Grand Canyon National Park in Arizona, builds a footbridge over the Colorado River at the bottom of the canyon. The footbridge permits interspersal of two closely related antelope squirrels. Previously, one type of squirrel had been restricted to the terrain south of the river, and the other type had been restricted to terrain on the north side of the river. Immediately before and ten years after the bridge's completion, ten antelope squirrels from both sides of the river were collected, blood samples were taken, and frequencies of alleles unique to the two types of antelope squirrels were determined (see graphs below).

-Upon undergoing change, which of these genes is most likely to result in speciation while a geographic barrier separates two populations of a flowering-plant species?
A)one that affects the rate of chlorophyll a synthesis 
B)one that affects the amount of growth hormone synthesized per unit time 
C)one that affects the compatibility of male pollen and female reproductive parts 
D)one that affects the average depth to which roots grow down through the soil 
E)one that affects how flexible the stems are

Quizplus · Accepted Answer

The gene that affects the compatibility of male pollen and female reproductive parts is most likely to result in speciation while a geographic barrier separates two populations of a flowering-plant species because it can lead to reproductive isolation between the two populations. This means that even if the two populations come back into contact later, they may no longer be able to interbreed and exchange genes, which is a key factor in the development of new species. The other genes listed may affect various aspects of plant growth and development, but they are less likely to lead to reproductive isolation and speciation.

The Following Questions Refer to the Paragraph and Graphs Below