T H E AMERICAN NATURALIST VOL. XXXVI. iA ll', I902. No. 425. THE LAW OF ADAPTIVE RADIATION. HENRY FAIRFIELD ()SBORN.ONE of the essential features of divergent evolution as conceived in the branching system successively developed by Lamarck, Darwin, Huxley, and Cope has been termed by the writer " adaptive radiation." This term seems to express most clearly the idea of differentiation of habit in several directions from a primitive type, as shown in the accompanying diagrams. The law is a familiar one ; it results in the formation of analogous radii in different groups of animals. The first comprehensive illustration of the law known to the writer is that under the headings " Homologous Groups " and " Heterology," in Cope's paper of i868 on the "Origin of Genera," reprinted in the Orzrin of the Fittest (pp. 95-io6).This brilliant essay is marred only by great confusion in the use of terms; but the parallelisms in unrelated groups of amphibians and of mammals such as marsupials and placentals, as first observed by Owen, are clearly brought out.In the present paper citations from earlier essays of my own may be given bearing upon gnci-erl adaplive radiation and the independent production of analogous radii under the convergent 353
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.