Note 295 — Chapter VI · —Geographical Area

On purely geographical grounds, also, a large area stimulates differentiation by presenting a greater diversity of natural conditions, each of which tends to produce its appropriate species or variety.295 Consider the different environments found in a vast and varied continent like Eurasia, which extends from the equator far beyond the Arctic Circle, as compared with a small land-mass like Australia, relatively monotonous in its geographic conditions; and observe how much farther evolution has progressed in the one than in the other, in point of animal forms, races and civilization. If we hold with Moritz Wagner and others that isolation in naturally defined regions, alternating with periods of migration, offers the necessary condition for the rapid evolution of type forms, and thus go farther than Darwin, who regards isolation merely as a fortunate contributory circumstance, we find that for the evolution of mankind it is large areas like Eurasia which afford the greatest number and variety of these naturally segregated habitats, and at the same time the best opportunity for vast historical movements.