32 MAN --AN ADAPTIVE MECHANISM 



tion to his environment is this quality of versatility. 

 By means of this quality expressed through the mani- 

 fold reactions of his highly organized central nervous 

 system, man has been able to dominate the beasts, 

 and to maintain himself in an environment many times 

 more extensive than theirs. Like the defensive mech- 

 anisms of shells, poisons and odors, man's partic- 

 ular defensive mechanism his versatility of nerv- 

 ous response (mind) was acquired automatically 

 as the result of a particular combination of circum- 

 stances in his environment. 



The Rise of Man 



In the Tertiary era some twenty millions of years 

 ago the earth, basking in the warmth of a tropical 

 climate, had produced a luxuriant vegetation, and a 

 swarming progeny of gigantic small-brained animals 

 for which the exuberant vegetation provided abundant 

 and easily acquired sustenance. They were a breed 

 of huge, clumsy and grotesque monsters, vast in bulk 

 and strength, but of little intelligence, that wandered 

 heavily on the land and gorged lazily on the abundant 

 food at hand. At that time there prevailed such types 

 as the giant dinosaurs, mere feeding and breeding 

 machines. They were essentially the product of pros- 

 perous days, destined to perish at the first onslaught 

 of adversity. With the advance of the carnivora, the 

 primitive forerunners of our tigers, wolves, hyenas and 

 foxes, came a period of stress, comparable to a seven 

 years of famine following a seven years of plenty, which 

 subjected the stolid herbivorous monsters to a severe 

 selective struggle. 



