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:''For the 19th-century New York politician, see Augustus Weismann.'' Friedrich Leopold August Weismann (17 January 1834 – 5 November 1914) was a German evolutionary biologist. Ernst Mayr ranked him the second most notable evolutionary theorist of the 19th century, after Charles Darwin. Weismann became the Director of the Zoological Institute and the first Professor of Zoology at Freiburg. His main contribution was the germ plasm theory, at one time also known as ''Weismannism'',〔Romanes, George John. ''An examination of Weismannism''. The Open court publishing company in Chicago 1893 ()〕 according to which (in a multicellular organism) inheritance only takes place by means of the germ cells—the gametes such as egg cells and sperm cells. Other cells of the body—somatic cells—do not function as agents of heredity. The effect is one-way: germ cells produce somatic cells and are not affected by anything the somatic cells learn or therefore any ability the an individual acquires during its life. Genetic information cannot pass from soma to germ plasm and on to the next generation. This is referred to as the Weismann barrier.〔(Germ-Plasm, a theory of heredity (1893)- Full online text ). Esp.org. Retrieved on 2012-02-25.〕 This idea, if true, rules out the inheritance of acquired characteristics as proposed by Jean-Baptiste Lamarck.〔Huxley, Julian 1942. ''Evolution, the modern synthesis''. p. 17〕 The idea of the Weismann barrier is central to the modern evolutionary synthesis, though it is not expressed today in the same terms. In Weismann's opinion the largely random process of mutation, which must occur in the gametes (or stem cells that make them) is the only source of change for natural selection to work on. Weismann was one of the first biologists to deny soft inheritance entirely.〔(Essays upon heredity (1889) Oxford Clarendon Press – Full online text ). Esp.org. Retrieved on 2012-02-25.〕 Weismann's ideas preceded the rediscovery of Gregor Mendel's work, and though Weismann was cagey about accepting Mendelism, younger workers soon made the connection. Weismann is much admired today. Ernst Mayr judged him to be the most important evolutionary thinker between Darwin and the evolutionary synthesis around 1930–40, and was "one of the great biologists of all time".〔Mayr, Ernst 1982. ''The growth of biological thought''. Harvard. p. 698〕 == Life == 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「August Weismann」の詳細全文を読む スポンサード リンク
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