1

1.Describe how geographic isolation can result in the formation of two distinct species.

2.Explain why geographic isolation of a population does not have to be maintained forever for speciation to occur.

Grand Canyon

The Grand Canyon in Arizona serves as a barrier to gene flow. While birds easily cross the Grand Canyon, it is impassable to rodents. As a result, the same bird species inhabit either side of the canyon, yet different species of squirrels inhabit opposite sides of the canyon.

With respect to the different populations, the Grand Canyon is

a.) a biological barrier to the squirrels

b )a biological barrier to the birds

c) a geographical barrier to the birds

d) a geographical barrier to the squirrels.