Disruptive selection means that the most common trait is being removed from the population. In directional selection means that a population is shifting in one direction toward an extreme trait.
Aside from decreasing genetic variation they both are not normal Gaussian curves. Disruptive selection has two normal curves at either end of the distribution. Directed selection has an abnormal...
Stabilizing selection is where a population is favored by just the right amount of a certain trait, and if they don't have the right amount of that certain trait then they die. Example: Human babies...