FUTURE OF MAN — MATHER 219 



destiny, but there is nothing in the record which guarantees that he 

 will use that power wisely. 



The animal species that in the past have been able to maintain their 

 existence for more than 2 or 3 million years are relatively few in 

 number. Most of them were comparatively simple types belonging 

 to the less highly organized branches or phyla of the animal kingdom. 

 Many were inhabitants of the sea where environmental conditions 

 were remarkably stable throughout long periods of time. Among 

 placental mammals, the major subdivision of the vertebrates to which 

 man belongs, there is no similar record of longevity. Except under 

 extraordinary conditions of geographic isolation, no species of pla- 

 cental mammal has persisted more than 2 or 3 million years. No 

 matter how successful it may have been temporarily in multiplying 

 and spreading over the face of the earth, each has become extinct 

 in a geologically brief span of time. Perhaps a half million years 

 might appropriately be taken as the average "life" of a species in 

 this group of highly organized and notably complex creatures. 



But extinction does not necessarily mean failure ; it has frequently 

 indicated the acme of achievement. For example, some of the now 

 extinct three-toed horses and four-toed camels passed on "the torch 

 of progress" to their descendants, the one-toed horses and two-toed 

 camels, and thus gained long-continuing security for their kind. 



What then does the future hold for mankind? Genus Homo has 

 already existed for 3 or 4 hundred thousand years ; the species Honw 

 sapiens has about 50 thousand years to its credit. If the average 

 applies, we may expect nearly or quite a half million years more of 

 existence for our kind and then either oblivion as we reach the end 

 of a blind alley or progressive development into some type of de- 

 scendant better adjusted than we to the total environmental factors 

 of the time. 



in 



But does the average apply ? Must man exit from the scene through 

 either of the doors, that which closed behind the dinosaurs and 

 titanotheres or that which opened before the three-toed horses and 

 notharctines? 



Most creatures have gained security by specializing in adjustment 

 of structure and habit to particular environmental conditions, whereas 

 man is a specialist in adjustability of structures and habits to a vari- 

 ety of environments. No other vertebrate can live as can he on Ant- 

 arctic ice cap, in Amazonian jungle, beneath the surface of the sea, or 

 high in the air. 



Furthermore, man is the world's foremost specialist in transforming 

 environments to bring them within the range of his powers. Far 



