Darwinian fitness1) directional selection 2) disruptive selection 3) stabilizing selection- Genetic drift, gene flow, and even mutation can cause evolution, but they do not necessarily lead to adaptation. Only natural selection promotes adaptation.* Darwinian fitness is the contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals. - Three general outcomes of natural selection* Directional selection shifts the phenotypic “curve” of a population. It selects in favor of some extreme phenotype.