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Moritz Wagner (Bayreuth, 3 October 1813 – Munich, 31 May 1887) was a German explorer, collector, geographer and natural historian. Wagner devoted three years (1836–1839) to the exploration of Algiers:〔Wagner, Moritz 1841. ''Reisen in der Regentschaft Algier in den Jahren 1836, 1837 und 1838''. 3 vols, Leipzig.〕 it was here that he made important observations in natural history, which he later supplemented and developed: that geographical isolation could play a key role in speciation. From 1852–1855, together with Carl Scherzer, Wagner travelled through North and Central America and the Caribbean. In May 1843, Wagner toured the Lake Sevan region of Armenia with Armenian writer Khachatur Abovian. He committed suicide in Munich, aged 73. His brother Rudolf was a physiologist and anatomist. == Wagner's significance in evolutionary biology == Wagner's early career was as a geographer, and he published a number of geographical books about North Africa, the Middle East, and Tropical America. He was also a keen naturalist and collector, and it is for this work he is best known among biologists. Ernst Mayr, the evolutionist and historian of biology, has given an account of Wagner's significance.〔Mayr E. 1982. ''The growth of biological thought: diversity, evolution and inheritance''. Harvard.〕p562–565. However, others disagree with this account.〔Sulloway F.J. 1979. Geographic isolation in Darwin's thinking: the vicissitudes of a crucial idea. ''Studies in the History of Biology'' 3, p23-65.〕 During his three years in Algeria, he (amongst other activities) studied the flightless beetles ''Pimelia'' and ''Melasoma''. In these genera, a number of species are each confined to a stretch of the north coast between rivers which descend from the Atlas mountains to the Mediterranean. As soon as one crosses a river, a different but closely related species appears.〔Wagner M. 1841. ''Reisen in der Regentschaft Algier in den Jahren 1836, 1837 & 1838''. Voss, Leipzig. p199-200〕 Wagner made similar observations in the Caucasus and in the Andean valleys, leading him to conclude, after the ''Origin of Species'' had been published:〔Wagner M. 1873. ''The Darwinian theory and the law of the migration of organisms''. Translated by J.L. Laird, London. Google Books: http://books.google.com/books?id=o9faAAAAMAAJ&printsec=frontcover&source=gbs_v2_summary_r&cad=0#v=onepage&q&f=false 〕 :"... an incipient species will only () when a few individuals transgress the limiting borders of their range... the formation of a new race will never succeed... without a long continued separation of the colonists from the other members of their species." This was an early description of the process of geographic speciation by means of the founder effect. Another formulation of this idea came later: "Organisms which never leave their ancient area of distribution will never change".〔Wagner, M. 1889. ''Die Entstehung der Arten durch räumliche Sonderung''. Schwalbe, Basel. p82〕 Wagner's idea met with a mixed reception. "Unfortunately, Wagner combined (idea ) with some peculiar ideas on variation and selection" (Mayr). The leading evolutionists (Darwin, Wallace, Weismann) attacked Wagner's idea of geographic speciation, and it suffered a long decline until in 1942 it was reintroduced by Mayr.〔 The importance of geographic speciation became one of the core ideas of the evolutionary synthesis.〔Huxley J.S. 1942. ''Evolution: the new synthesis''. Allen & Unwin, London.〕 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「Moritz Wagner」の詳細全文を読む スポンサード リンク
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