Which evolutionary mechanism can help drive sympatric speciation through sexual selection?

Disruptive selection is the correct mechanism that can drive sympatric speciation through sexual selection. This type of selection occurs when extreme traits that diverge from the average phenotype are favored over intermediate traits in a population. In the context of sexual selection, individuals with extreme traits might attract mates more successfully than those with average traits.

As a result, this preferential mating can enhance reproductive isolation within a population, as individuals start to mate based on these extreme traits rather than the average phenotype, leading to the formation of distinct subpopulations. Over time, this can culminate in the emergence of new species without a geographic barrier, as the two subpopulations may evolve independently due to their preference for different mating choices.

The other mechanisms listed do not specifically facilitate sympatric speciation through sexual selection in the same way. Natural selection, directional selection, and stabilizing selection tend not to create the types of reproductive isolation needed for sympatric speciation. Instead, they often result in populations that are more homogeneous or shift towards a single advantageous trait rather than promoting divergence among subpopulations.