Used to describe the combination of natural selection and genetics
Friedrich Leopold August Weismann, considered the "founder of Neo-Darwinism" for expanding Darwin's theory along genetic linesGeorge John Romanes originally usedNeo-Darwinism in 1895 to refer to an early modification of Darwin's theory. Photograph by Elliott & Fry (1896)
Neo-Darwinism is generally used to describe any integration ofCharles Darwin's theory ofevolution bynatural selection withGregor Mendel's theory ofgenetics. It mostly refers to evolutionary theory from either 1895 (for the combinations of Darwin's andAugust Weismann's theories of evolution) or 1942 ("modern synthesis"), but it can mean any new Darwinian- and Mendelian-based theory, such as the current evolutionary theory.
Darwin's theory of evolution by natural selection, as published in 1859, provided a selection mechanism for evolution, but not a trait transfer mechanism.Lamarckism was still a very popular candidate for this.August Weismann andAlfred Russel Wallace rejected the Lamarckian idea ofinheritance of acquired characteristics that Darwin had accepted and later expanded upon inhis writings on heredity.[1]: 108[2][3] The basis for the complete rejection of Lamarckism was Weismann'sgerm plasm theory. Weismann realised that the cells that produce the germ plasm, orgametes (such assperm andeggs inanimals), separate from thesomatic cells that go on to make other body tissues at an early stage in development. Since he could see no obvious means of communication between the two, he asserted that the inheritance of acquired characteristics was therefore impossible, a conclusion now known as theWeismann barrier.[4]
It is, however, usuallyGeorge Romanes who is credited with the first use of the word in a scientific context. Romanes used the term to describe the combination ofnatural selection and Weismann's germ plasm theory that evolution occurs solely through natural selection, and not by the inheritance of acquired characteristics resulting from use or disuse, thus using the word to mean "Darwinism without Lamarckism."[5][6][7]
Following the development, from about 1918 to 1947, of themodern synthesis ofevolutionary biology, the term neo-Darwinian started to be used to refer to that contemporary evolutionary theory.[8][9]
Biologists, however, have not limited their application of the termneo-Darwinism to the historical synthesis. For example,Ernst Mayr wrote in 1984 that:
The termneo-Darwinism for the synthetic theory [of the early 20th century] is sometimes considered wrong, because the term neo-Darwinism was coined by Romanes in 1895 as a designation of Weismann's theory.[10][11][7][12]
Publications such asEncyclopædia Britannica useneo-Darwinism to refer to current-consensus evolutionary theory, not the version prevalent during the early 20th century.[13] Similarly,Richard Dawkins andStephen Jay Gould have usedneo-Darwinism in their writings and lectures to denote the forms of evolutionary biology that were contemporary when they were writing.[14][15]
^Kutschera, Ulrich (December 2003). "A comparative analysis of the Darwin-Wallace papers and the development of the concept of natural selection".Theory in Biosciences.122 (4):343–359.doi:10.1007/s12064-003-0063-6.ISSN1431-7613.S2CID24297627.
^Barbieri, Francisco D. (1989). "The origin of Metazoa and Weismann's germ line theory".Rivista di Biologia.82 (1):61–74.ISSN0035-6050.PMID2665023.
^Bock, Walter J. (July 1981). "Reviewed Work:The Evolutionary Synthesis. Perspectives on the Unification of Biology".The Auk.98 (3):644–646.ISSN0004-8038.JSTOR4086148.
