Diversifying or disruptive selection is a version of natural selection that pushes population traits to both extremes and selects against the average individual. It is the rarest type of natural selection.
An example of diversifying selection occurs with peppered moths in London. Moths in rural areas tended to be very light in color while living those near industrial areas were very dark. Both locations had very few medium-colored moths. The lighter-colored moths were camouflaged in rural areas but were very visible in industrial areas, so only thrived in rural areas. The darker moths were hard to see in industrial areas and so were better able to survive compared to moths of other colors. The medium-colored moths were not camouflaged in either area and were therefore uncommon in both.