Neo-Darwinism

Neo-Darwinism

[nee-oh-dahr-wi-niz-uhm]
Neo-Darwinism is a term used to describe certain ideas about the mechanisms of evolution that were developed from Charles Darwin's original theory of evolution by natural selection: while separating them from his hypothesis of Pangenesis as a Lamarckian source of variation involving blending inheritance. The term was first used by George Romanes in 1895 to refer to the idea that evolution occurs solely through natural selection, as proposed by Alfred Russel Wallace and August Weismann, in other words, without any mechanism involving the inheritance of acquired characteristics resulting from use or disuse. These two scientists' complete rejection of Lamarckism came from Weissmann's germ plasm theory. Weissman realised that the cells that produce the germ plasm, or gametes (such as sperm and egg in animals), separate from the somatic 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 Weismann's barrier.

From the 1880s to the 1930s the term continued to be applied to the panselectionist school of thought, which argued that natural selection was the main and perhaps sole cause of all evolution. From then until around 1947 the term was used for the panselectionist followers of R. A. Fisher.

Modern evolutionary synthesis

Following the development, from about 1937 to 1950, of the modern evolutionary synthesis, now generally referred to as the synthetic view of evolution or the modern synthesis, the term neo-Darwinian has been used by some to refer to modern evolutionary theory. However, such usage has been described as incorrect; with Ernst Mayr writing in 1984:

Despite this, publications such as the Encyclopaedia Britannica, use this term to refer to current evolutionary theory. This term is also used in the scientific literature, with the academic publishers Blackwell Publishing referring to "neo-Darwinism as practised today", and some figures in the study of Evolution like Richard Dawkins and Stephen Jay Gould, using the term in their writings and lectures.

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