To solve the problem below, you must provide a clear and convincing justification for accepting one of the possible answer choices as the best or most appropriate and for rejecting each of the other choices as less appropriate.
A student argued that populations and species occupying distant islands are not genetically isolated because individual organisms from the mainland can be blown across the ocean and reach the islands. Therefore, one would not expect islands to evolve species different from those on the mainland. Which of the following would be the most serious criticism of the student's argument?
a. If populations are not geographically isolated, then there can be gene flow and species formation will be prevented.
b. Several different species will exist on an island even though it is isolated.
c. Even though island populations are isolated, several new species can evolve due to different selection pressure on the island.
d. If an island is relatively close to a continent, highly mobile species, such as birds, can fly back and forth between the island and the mainland.
e. Entry of related organisms to island populations can be sufficiently rare such that new species will evolve despite the occasional entry of outside organisms.
