Moritz Wagner (naturalist)

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:[1] 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.

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.

[5] Wagner made similar observations in the Caucasus and in the Andean valleys, leading him to conclude, after the Origin of Species had been published:[6] This was an early description of the process of geographic speciation by means of the founder effect.

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.

[9] Some modern experts such as Ernst Mayr, Jerry Coyne and H. Allen Orr,[10] argue that Wagner pioneered the idea of geographical speciation, and that Darwin had not appreciated it.

[12] Jordan later wrote a brief note of correction agreeing with some of Gulick's criticisms: In a later paper Gulick says that "Moritz Wagner, in his 'Law of the Migration of Organisms,' was the first to insist on the importance of geographical isolation as a factor in evolution, but when he asserted that without geographical isolation natural selection could have no effect in producing new species he went beyond what could be sustained by facts".

The importance of Wagner's insight is highly debatable today, as it is clear that geographical isolation is not the only mechanism which causes species-splitting.

Much of the good in Wagner's ideas is masked by his other, mistaken, beliefs,[18] but his inferences about geographical speciation were important insights gained by observation of insects in their natural habitats.