Explain how speciation, directional, disruptive, and stabilizing selection affect biodiversity.

Speciation forms new species.Directional selection favors one extreme of a phenotype, which leads to evolution and adaptive change of a species.Disruptive selection selects against the average and leads to evolution and genetic variation of a species.Stabilizing selection favors the average individual in a population, which does not lead to adaptive change or evolution, and reduces variation.