Time element.
The complexity of this problem does not end here. The modification of human development by environment is a natural process; like all other natural processes, it involves the cumulative effects of causes operating imperceptibly but persistently through vast periods of time. Slowly and deliberately does geography engrave the subtitles to a people's history. Neglect of this time element in the consideration of geographic influences accounts equally for many an exaggerated assertion and denial of their power. A critic undertakes to disprove modification through physical environment by showing that it has not produced tangible results in the last fifty or five hundred years. This attitude recalls the early geologists, whose imaginations could not conceive the vast ages necessary in a scientific explanation of geologic phenomena.
The theory of evolution has taught us in science to think in larger terms of time, so that we no longer raise the question whether European colonists in Africa can turn into negroes, though we do find the recent amazing statement that the Yankee, in his tall, gaunt figure, "the colour of his skin, and the formation of his hair, has begun to differentiate himself from his European kinsman and approach the type of the aboriginal Indians."[28] Evolution tells the story of modification by a succession of infinitesimal changes, and emphasizes the permanence of a modification once produced long after the causes for it cease to act. The mesas of Arizona, the earth sculpture of the Grand Canyon remain as monuments to the erosive forces which produced them. So a habitat leaves upon man no ephemeral impress; it affects him in one way at a low stage of his development, and differently at a later or higher stage, because the man himself and his relation to his environment have been modified in the earlier period; but traces of that earlier adaptation survive in his maturer life. Hence man's relation to his environment must be looked at through the perspective of historical development. It would be impossible to explain the history and national character of the contemporary English solely by their twentieth century response to their environment, because with insular conservatism they carry and cherish vestiges of times when their islands represented different geographic relations from those of to-day. Witness the wool-sack of the lord chancellor. We cannot understand the location of modern Athens, Rome or Berlin from the present day relations of urban populations to their environment, because the original choice of these sites was dictated by far different considerations from those ruling to-day. In the history of these cities a whole succession of geographic factors have in turn been active, each leaving its impress of which the cities become, as it were, repositories.
Effect of a previous habitat.
The importance of this time element for a solution of anthropo-geographic problems becomes plainer, where a certain locality has received an entirely new population, or where a given people by migration change their habitat. The result in either case is the same, a new combination, new modifications superimposed on old modifications. And it is with this sort of case that anthropo-geography most often has to deal. So restless has mankind been, that the testimony of history and ethnology is all against the assumption that a social group has ever been subjected to but one type of environment during its long period of development from a primitive to a civilized society. Therefore, if we assert that a people is the product of the country which it inhabits at a given time, we forget that many different countries which its forbears occupied have left their mark on the present race in the form of inherited aptitudes and traditional customs acquired in those remote ancestral habitats. The Moors of Granada had passed through a wide range of ancestral experiences; they bore the impress of Asia, Africa and Europe, and on their expulsion from Spain carried back with them to Morocco traces of their peninsula life.
A race or tribe develops certain characteristics in a certain region, then moves on, leaving the old abode but not all the accretions of custom, social organization and economic method there acquired. These travel on with the migrant people; some are dropped, others are preserved because of utility, sentiment or mere habit. For centuries after the settlement of the Jews in Palestine, traces of their pastoral life in the grasslands of Mesopotamia could be discerned in their social and political organization, in their ritual and literature. Survivals of their nomadic life in Asiatic steppes still persist among the Turks of Europe, after six centuries of sedentary life in the best agricultural land of the Balkan Peninsula. One of these appears in their choice of meat. They eat chiefly sheep and goats, beef very rarely, and swine not at all.[29] The first two thrive on poor pastures and travel well, so that they are admirably adapted to nomadic life in arid lands; the last two, far less so, but on the other hand are the regular concomitant of agricultural life. The Turk's taste to-day, therefore, is determined by the flocks and herds which he once pastured on the Trans-Caspian plains. The finished terrace agriculture and methods of irrigation, which the Saracens had learned on the mountain sides of Yemen through a schooling of a thousand years or more, facilitated their economic conquest of Spain. Their intelligent exploitation of the country's resources for the support of their growing numbers in the favorable climatic conditions which Spain offered was a light-hearted task, because of the severe training which they had had in their Arabian home.
The origin of Roman political institutions is intimately connected with conditions of the naturally small territory where arose the greatness of Rome. But now, after two thousand years we see the political impress of this narrow origin spreading to the governments of an area of Europe immeasurably larger than the region that gave it birth. In the United States, little New England has been the source of the strongest influences modifying the political, religious and cultural life of half a continent; and as far as Texas and California these influences bear the stamp of that narrow, unproductive environment which gave to its sons energy of character and ideals.