TWO PATTERNS OF LIFE 21 



It has been a long and devious road from the first divergence 

 of life along the two patterns of living to the present day com- 

 plexity of the living world. As evolution progressed, the members 

 of both kingdoms became increasingly different from one another, 

 but there has always been a dependence of heterotrophic organ- 

 isms upon green plants since they alone held the secret of the 

 conversion of sunshine, air, water and a few common minerals 

 of the earth's crust into food. This has brought about a web of 

 inter-relations between plant and animal species which has 

 profoundly influenced the evolution of both. Plants have always 

 been the pioneers and the vital mainstay of animal and human 

 life. They were the advance guard to colonize the land as organ- 

 isms left their aquatic birthplace to venture upon dry land. After 

 a few members of the plant kingdom had secured a foothold on 

 the previously barren rocky areas, numerous animal species 

 followed. Even today mosses and lichens are the pioneers in 

 populating bare rock areas and lifeless cliffs; to be followed by 

 an increasing assemblage of grasses, ferns, shrubs and trees which 

 get a foothold in what humus these pioneers leave behind them. 

 As soon as the mat of vegetation becomes complete a new world 

 of insects, worms, and numerous vertebrates can populate the 

 region which now offers them food and shelter. Where plants go, 

 animals may follow; thus plants determine where and how ani- 

 mals shall live. In fact the kind of animal life is directly corre- 

 lated with the evolving character of the plants in the same region. 

 Hoofed animals go with grasses, as do broad grinding molar 

 teeth. Perhaps one reason we as primates have arms with pre- 

 hensile hands instead of four legs like a horse is that our ancestors 

 lived among trees; climbing could not become a characteristic 

 activity of prairie-dwelling species. 



With the universal dependence of animals upon plants for 

 food, man is no exception to the rule when his existence is 

 dependent upon the products of forests and farms. On the whole, 

 the autotrophic pattern of living has been, and always will be, a 

 tremendous asset to mankind. It can not be said that the reverse 

 is also true; the greatest enemy of the plant world is often man 

 himself. Wasteful and unappreciative of the benefits to be derived 

 from a correct relationship with plant life, he has often destroyed. 



