THE VOYAGE OF EVOLUTION lOT 



as he rises in the scale of evolution and of civilization? In order 

 to answer these questions let us go back to early geological times 

 and review man's voyage of evolution. 



Long before man's earliest ancestors had become different 

 from the beasts the whole world of life had realized the necessity 

 of air. Even the creatures that inhabit the water can live only 

 by taking from it the dissolved air. Otherwise the chemical 

 activities which are the basis of all life come promptly to an end. 

 Before these primitive animals could give rise to higher forms, 

 however, it was necessary that they should pass through a series 

 of crises. Each of these crises was a step forward toward the 

 estate of man. Each has left its impress not only upon the 

 animal world but upon the human race. A few of these crises, 

 such as the development of vertebrates from invertebrates, were 

 due to causes other than climate, but most arose directly from 

 the conditions of the air which we call climate. Let us consider 

 three of the chief crises. The first was the emergence of the 

 earliest vertebrates from the water. This was a most momentous 

 step, for only in the highly varied environment of the land does 

 brain power develop rapidly. Creatures like the seal, the whale, 

 and the manatee, which have gone back to the water from the land, 

 fall behind in the mental race, for they are not sufficiently stimu- 

 lated. The second great crisis was the change which caused 

 certain forms of life to become warm-blooded. This not only 

 enabled man's animal ancestors to continue their vital activities 

 at all seasons and in almost all parts of the world, but it gave 

 rise to the close bond between mother and child which has been the 

 greatest of all factors in promoting the higher qualities of love 

 and altruism. The third great crisis was the separation of man — 

 the two-handed, two-footed, big-brained creature — from his four- 

 handed and smaller-brained relatives. This was the time when 

 mental qualities evolved most rapidly. Therefore it interests us 

 most of all because the conditions which fostered the evolution 

 of our minds are those which today stimulate them most strongly. 



