Question

Consider the following scenario:
Some fish in a murky underground lake have lighter scales than the others. This makes it slightly harder for the lighter fish to escape detection by predators, but most light-colored fish live long enough to reproduce. A natural event separates the dark-scaled fish from their light-scaled cousins, and as a result, a new species of dark-scaled fish emerges.
Which statement accurately describes the scenario?
(1 point)
• The fish experienced an evolutionary change because of natural selection.
• The fish survived because of an inheritable advantage.
• The fish experienced an evolutionary change because of genetic drift.
The fish survived because of a non-genetic advantage.

Answer 1

"The fish experienced an evolutionary change because of genetic drift." (Option 3)

Explanation: the new dark‑scaled species arose after a natural event geographically separated a subset of the population. That isolation (a founder/bottleneck situation) can change allele frequencies by chance (genetic drift) and lead to speciation, rather than being driven by natural selection for scale color.