Animal Sciences Commons^™

An Electrophoretic Study Of Egg-White Proteins In Twenty-Three Breeds Of The Domestic Fowl, Charles G. Sibley, Paul A. Johnsgard

Paul Johnsgard Collection

A "conservative" taxonomic character is one which preserves evidence of evolutionary relationships. As Mayr (1942: 296) points out such characters are rare because structures are usually lost quickly when no longer needed and selection seldom neglects a functional structure for very long but continually modifies it as adaptive fitness is increased. However, because different characters evolve at different rates it is possible to find some characters which have changed more slowly than others and to use these as phylogenetic indicators. In birds, for example, plumage color and structure apparently change more rapidly than the skeleton or the muscular system. This …