^43 ORGANIC EVOLUTION 



scribe to either of these statements. From moved the descendants of the opossum 

 what we know of the past it seems Ukely would soon fill the spaces left and there 

 that as long as there is life on earth there would be rapid evolution among the van- 

 will be continuing change or evolution, ous forms, just as there was m Australia. 

 The directions it will take are unpredict- Likewise, if the human spec.es came to 

 able to us now, but that it will continue an abrupt end, the spaces left would be 

 seems assured. fl»«d by other forms, perhaps not exact 



To be sure, the abundance of life in ex- duplicates but certamly some possessing 

 istence now might suggest that all of the the unique qualities of man. For example, 

 possible environments capable of support- high intelligence has h'S^ surviva value 

 ing life have been taken, leaving no room and would undoubtedly be se ected for 

 fo? any more forms. A similar situation again. The entire trend m evolution has 

 might have seemed to be true even in the been toward a more intricate coordmating 

 Cambrian, where all of the present phyla system, and there is no reason to beheve 

 had their representatives. There were fewer that such a trend would cease if there were 

 niches then but all of them were probably no animals possessing those qualities on 

 filled, and as ages passed new niches ap- the earth. To be sure, no other groups are 

 peared and new species filled them. There likely to usurp that position among animals 

 [s no reason to believe that a similar process so long as man maintains his present place, 

 is not going on at the present time. New Unless he retrogresses, it is highly improb- 

 environmente are constantly being created able that any other group could match or 

 and those animals with an ample supply of excel him in reasoning power, 

 mutations move into them, with the aid of What does future evolution hold for 

 "atural selection. Obviously there will come man? Can he profit by what he knows 

 a time, perhaps a billion or so years in the about this grand drama of evolution, can 

 future when all life will cease, but up to he control its future trends with respect to 

 the bitter end living things will undoubt- the animals around him, and most impor- 

 edl attempt to adapt. tant, can he control ,t with respect to his 



It is highly probable that the evolution own destiny? These are the really impor- 

 of certain groups could be repeated if the tant problems that scientists and laymen 

 ones living today were wiped out. Many alike wish to understand and, of course, 

 of the "immortal" such as Sphenodon and they are the most difficult to answer. We 

 the opossum are still with us and perhaps might speculate briefly about them m the 

 they could radiate once again, giving rise closing sentences of this book, 

 to new groups of reptiles and mammals. The evolution of man has placed him m 



Undoubtedly the new forms would not be a unique position among amrnals m that he 

 exactly like the ones we see today, but they is the first and only animal who can control 

 might be as diversified. One might ask why his environment to a greater or esser ex- 

 thl opossum has not done this' very thing tent. He builds shelters, clothes his body, 

 today why it is still essentially the same plans his food needs and provides for them, 

 creature that lived in the Cretaceous. The and in general improves his physical en- 

 most obvious reason is that placental mam- vironment wherever his own »;g»"'fy^"d 

 mals have occupied nearly all of the en- available materials will permit. He knows 

 vironments that are available to it and the enough about evolution to take advantage 

 competition gives it little opporhmity to of it in controlling animal and ij^ant life 

 crowd in. Hence it has been able only to around him. which enhances his own 

 maintain itself up to the present. But if chances for survival. In other words he 

 the placental mammals were suddenly re- can give evolution direction with a goal. He 



