Final answer:
Sympatric speciation generally requires disruptive selection, which favors extreme phenotypes, leading to reproductive isolation and creation of new species within the same habitat.
Step-by-step explanation:
In general, sympatric speciation requires the action of disruptive selection acting against hybrids. Disruptive selection plays a crucial role in sympatric speciation by favoring extreme phenotypes over intermediate ones, thereby driving the divergence within a population sharing the same habitat. This pattern of selection can eventually lead to reproductive isolation and form new species without physical barriers. It contrasts with directional selection which favors one extreme phenotype and stabilizing selection that favors the intermediate phenotype, or artificial selection that is influenced by human choice.