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XI 



Evolution 



THE question of man's origin is as old as man's reason. Our main method 

 of attack seems to be an ever-intensifying search for ancient men 

 and missing hnks. Comparatively speaking only a handful of men are en- 

 gaged in the search. Whereas many skeletons of early man have been 

 turned up in various parts of the world we still do not have a clear picture 

 of man's ancestors. 



Speaking broadly, the old controversy regarding the fact of evolution 

 is dying down. However the method of evolution is still a subject of much 

 debate. Whatever the name of the theory, the mechanism seems to be 

 gradually centering about the hereditary units, the chromosomes. The 

 genes themselves are apparently subject to change or mutation thereby 

 producing new effects. Chromosomes may become changed in number 

 in individuals through failures in the reduction cycle or through hybrid- 



ization or crossing. 



The layman is often heard asking the question "is evolution going on 

 today and if so where?" As Darwin correctly pointed out, evolution is a 

 slow process and it is as difficult to observe as the gradual descent of the 

 glaciers in the ice age was to the animals of that time. However, plant and 

 animal geneticists have started interesting lines of research here and have 

 found that they can hasten the natural process considerably by species 

 crossing, genera crossing, x-rays and other methods. Actually several score 

 of new species of plants and animals have been "created" in this way, 

 many of them perfectly fertile. This is rather a new avenue of approach and 

 the future is very bright indeed for an increase in our knowledge of ev- 

 olution. 



THE AGE OF HOMO SAPIENS * 



W. W. HO WELLS 



It is customary to speak of the time since the beginning of the Ice Age, 

 or the last million years, as the Age of Man, because its geological deposits 

 are embellished with the stony fruits of human handiwork as well as with 



* Reprinted by permission of the Scientific Monthly, American Association for the 

 Advancement of Science. Copyright 1941. 



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