My life : a record of events and opinions - Wallace-online.org

MY CHARACTER—NEW IDEAS 383modified in accordance with this necessity. Thispaper forms chapter vi. of my " Natural Selection andTropical Nature."5. In the great subject of the origin, use, andpurport of the colours of animals, there are severalbranches which, I believe, I was the first to callspecial attention to. The most important of thesewas the establishment of the class of what I termed" Recognition colours," which are of importance inaffording means for the young to find their parents,the sexes each other, and strayed individuals ofreturning to the group or flock to which they belong.But perhaps even more important is the use of thesespecial markings or colours during the process of thedevelopment of new species adapted to slightlydifferent conditions, by checking intercrossing betweenthem while in process of development. It thusaffords an explanation of the almost universal rule,that closely allied species differ in colour or markingeven when the external structural differences areexceedingly slight or quite undiscoverable. Thesame principle also explains the general symmetryin the markings of animals in a state of nature, whileunder domestication it often disappears : difference ofcolour or marking on the two sides would renderrecognition difficult. This principle was first statedin my article on "The Colours of Animals andSexual Selection " (in " Natural Selection and TropicalNature," 1878) and more fully developed in "Darwinism."I am now inclined to think that it accountsfor more of the variety and beauty in the animalworld than any other cause yet discovered.I may here add that I believe I was first to giveadequate reasons for the rejection of Darwin's theory