Question

You are studying a potential case of incipient sympatric speciation involving two morphs of a cichlid fish in a crater lake that feed at different depths and differ in morphology. If true, which of the following statements would make sympatric speciation more likely (or at least possible)?

(A) The two morphs specialize on different food types; matings between the morphs produce offspring that are intermediate and can efficiently utilize both food types.
(B) The two morphs feed on different food types and there is strong disruptive selection operating such that individuals that are intermediate are very strongly selected against (basically none survive).
(C) The two morphs feed at different depths, but both morphs come to a rocky area near the shore to mate. Females prefer to mate with males of the other morph
(D) None of the above

Answer 1

Incipient sympatric speciation is more likely when two morphs specialize on different food types but can efficiently utilize both food types. Strong disruptive selection against intermediate individuals and mate preferences for individuals of the other morph can also contribute to sympatric speciation.

Step-by-step explanation:

Incipient sympatric speciation is more likely in a situation where the two morphs of a cichlid fish specialize on different food types, but their offspring can efficiently utilize both food types (Option A).

In this scenario, the two morphs will be able to occupy different ecological niches based on their food preferences. This can lead to reproductive isolation and the evolution of distinct species over time.

On the other hand, if there is strong disruptive selection against individuals that are intermediate in feeding behavior (Option B) or if both morphs mate in the same area but prefer to mate with individuals of the other morph (Option C), it can also contribute to sympatric speciation.