A line of indirect evidence of competition comes from the comparison between closely related species, whose population can be allopatric (geographically separated) or sympatric (geographically superimposed). In some cases, the allopatric populations of these species are morphologically similar and use similar resources. On the other hand, sympatric population, which are supposed to compete for resources, have body structures and use different resources. The displacement of characters is the tendency to have more divergent characteristics in sympatric populations of two species than in allopatric populations of the same two species.
An example of character displacement is the variation in size between populations of galapagos finches. Some of its populations are allopatric ( they live separately) and others are sympatric ( they live together). Peak size distributions they vary according to whether they are sympatric or allopatric. They look more alike when they are allopathic than when they are sympatric. That is, the peak size character moves when species enter competition.
Explanation:
Great white sharks are blue-gray on the dorsal, or top, part of their bodies. This helps them blend in with the bottom of the ocean when viewed from above. The belly, or ventral, part of the body, is white. This makes it difficult to see the sharks from below, with sunlight shining in around them.
