132 THE EVOLUTION OF MAN 



show the greatest physical diversities. He does not. Does 

 this mean that evolution stops short of man? Let us first get 

 some of the facts before us. 



Human beings are much alike over both time and space. 

 For many thousands of years man has been substantially the 

 same kind of a physical being as he is to-day. Over all the 

 earth he is pretty much the same sort of animal. One who 

 has followed the efforts of scientists to distinguish the varieties, 

 or races, of mankind can realize how essentially alike they are. 

 Conviction of this essential similarity has led to the assertion 

 that "man is unchanged in a changing environment." But this 

 seems to mean, on the face of it, that somewhere during the 

 course of human development evolution is suspended; for evo- 

 lution is adjustment to environment. 



Certainly mankind has encountered widely diverse environ- 

 ments. Men live in countries where the temperature falls far 

 below zero; also where it rises considerably over one hundred 

 degrees Fahrenheit. They inhabit regions which are cold 

 and dry, cold and damp, hot and dry, and hot. and damp. 

 They live at sea-level or thousands of feet above it. They 

 persist where there is much animal life of all kinds, or where 

 there is little of any kind. Of all animals the most widely 

 distributed over space, men have encountered all varieties of 

 earthly environment. Yet they are essentially alike. The 

 most widely distributed; the least changed "unchanged in a 

 changing environment." 



Through time also, with its secular and often radical 

 changes of life-conditions, alteration in man's physical make-up 

 has been relatively slight. Animals adjust even to so regular 

 and recurrent a set of conditions as the succession of the sea- 

 sons, while man has remained practically the same through 

 the protracted ups and downs of centuries and millenia. Is 

 it possible that the evolutionary process is stayed and that man 

 is exempted from it? Of course it is not halted; and he is 



