Scientists are not at all agreed as to the place of man's origin. It was once an article of faith that he arose in Central or Southern Asia, and this belief followed upon finding Aryan languages in Asia, but these are now known to have been taken there from Europe not more than 3,000 or 4,000 years ago.* Others are inclined to an origin in Africa, Europe and even America, and others again believe in more than one center of evolution.
All the facts are best explained by the theory of two separate centers, one in Central Europe and the other in the Central Asian plateau, the two races being kept apart until 10,000 to 15,000 years ago by some barrier such as that enormous inland sea which once extended from the Black Sea to the Arctic, submerging Western Asia, and of which the Caspian is a remnant. Though the types have since been inextricably mixed, there are enough pure races to describe the characteristics. The Eastern or Asian type has a broad face and broad head (brachycephalic), straight hair with round cross-section, and it is an unemotional placid race. The Western or European type has a long face, long head (dolicocephalic), wavy, curly or kinky hair with oval or flat cross-section, and it is an emotional, lively, excitable race.
From Central Asia the Eastern type spread over Asia to all the Pacific islands except, perhaps, Australasia, and thence, very much later, throughout America. The Western type flowed south over the whole of Africa at a very early time when there were far different geographic features between Europe and Africa making such migrations possible, such as that undoubted connection via Sicily. At a comparatively recent period long heads drif ted eastward by a southern route into Southern Asia, and are found in India now. After the Siberian Sea was drained by elevation of the land, and some other unknown barriers were removed, there started that western drift of broad heads into Europe by the northern route. It kept up until modern times, creating some of the most terrible history of Europe. So that we have in Europe a wedge-shaped mass of broad-headed descendants of Asiatic invaders, with its base in Eastern Russia and its apex in France, with overflows as far as Scotland and Ireland, and even Spain and Italy. The two types are separated in the Malay Archipelago as sharply as the two types of flora and fauna - Australian and Malaysian. Wallace was the first to note and define these types and has mentioned the vast difference between the lively New Guinea men and the quiet Malays.*
* Taylor, Origin of the Aryans.
Dual origin of closely related animals (either species or varieties) occurs in other animals as well as man. Nehring of Berlin, and Lehmann determined "that the dromedary and bactarian camel originated in two distinct regions, the former being a subtropical steppe and desert animal and the latter belonging to the subarctic steppes and desert."* This is merely the law of parallel evolution; that is, if two separated areas have similarly changing conditions and similar species to give variations each environment necessarily selects the same variations the other does, and they both evolve similar organisms. Given identical conditions, even the same civilizations arise in widely separated places, and this explains why there is a similarity in the evolution of widely separated societies, as those in Africa and primitive America.