The Law of Adaptive Radiation

Abstract

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

Founder niche constrains evolutionary adaptive radiation

“…More than a century ago, H. F. Osborn coined the term "adaptive radiation" to refer to the "differentiation of habit in several directions from a primitive type" that occurs during evolution (1). Since then, our understanding of adaptive radiation (in the modern definition) has greatly increased, but some dynamics remain hidden in evolutionary history.…”

“…niche evolution | ecological opportunity | biodiversity R apid diversification of a single lineage into organisms with different niches-adaptive radiation-underpins the evolution of biodiversity (1)(2)(3)(4). Here, we define a niche as the complex of reciprocal ecological interactions between an organism and its environment that governs organismal fitness (following refs.…”

“…[5][6][7]. Although the dynamics of adaptive radiation are determined by the interplay of many factors, two universal prerequisites are sufficiency of founder evolvability and availability of ecological opportunity (1)(2)(3)(4)(8)(9)(10)(11)(12). Founder evolvability concerns the maximal range of derived organisms with different niches that can be accessed from the founding ancestor by mutation and recombination over an interval of evolutionary time (3,8,(13)(14)(15)(16).…”

Δ6-Desaturase sequence evidence for explosive Pliocene radiations within the adaptive radiation of Macaronesian Echium (Boraginaceae)

“…Island radiations are associated with particular evolutionary processes conducive to adaptive radiation: genetic bottlenecks as populations initiate from a small number of colonists, rapid rate of phenotypic evolution by character release from previous ecological constraints, and novel adaptations as populations evolve into a range of new niches (Bromham and Woolfit, 2004). Lamarck (1809), Darwin (1859), and Haeckel (1866) used the concept of adaptive radiation to link environment and organismic evolution, although that term was formally proposed by Osborn (1902). Later on, Huxley (1942) defined adaptive radiation as 'an invasion of different regions of the environment by different lines within a group and secondarily their exploitation of different modes of life'.…”

Development of human limbs.

“…Besides, there is a disagreement about their mono or polyphyletic origin. Some scientists believe these animals are of polyphyletic origin [19,20,21,28,29], while others [16,30] are sure they are of monophyletic origin. Meanwhile, some facts are paid more attention to than others and important arguments of the opponents are undervalued.…”