Question

A species of fish known as Astyanax mexicanus lives in deep underground caves off the coast of Mexico. It is virtually blind. The same fish lives near the surface and has fully functioning eyes. Over time, what will most likely happen to the sighted and blind types of Astyanax mexicanus?
A. One type will become extinct.

B. They will become separate species.

C. They will interbreed and exhibit only the dominant trait.

D. One type will mutate to become more like the other.

Answer 1

Answer: B. They will become separate species.

Explanation:

Speciation is a process by which a new species develop from the existing species. Speciation occurs when the members of the same species get separated due to geographical, behavioral, temporal isolation these organisms becomes incapable of breeding among themselves results in the formation of population of distinct species.

In the given situation, this can be said that two species exhibit adaptations and features according to their habitat. Like the one which is residing in the underground caves is virtually blind as the cave water may remain unexposed to the sunlight therefore, in darkness no eye sight is required. But when the members of the same species live in surface waters they exhibited fully functioning eyes. These functioning eyes will help them to find food and escape from the predators. The fishes living in the caves and those living in near the surface are geographically isolated. Hence, this isolation will promote speciation.

Answer 2

B. They will become separate species.

Both traits are advantageous, so neither will take the trait of the other randomly. There is no reason to think either will necessarily go extinct.