444 ANIMAL BIOLOGY 



man developed some surgical skill as evidenced, in particular, by 

 skulls showing trepanation. So culture moved on apace to the 

 Age of Metals. 



4. Age of Metals 



The gradual transition from the Stone Age — Paleolithic, Meso- 

 lithic, and Neolithic — to the Age of Metals effected perhaps the 

 most important step in the history of human culture. It meant a 

 release from the restrictions inherent in the very nature of stone 

 and the opening up of the almost infinite possibilities of metals in 

 the fabrication of newer and better instruments and utensils. In- 

 vention was stimulated. 



This turning point in culture came with the development of the 

 art of extracting metals from their ores and of melting and casting 

 them. Copper was the first employed, probably because it was 

 available in its native condition, and led to a transition period, the 

 so-called Age of Copper. This later gave place to the great Bronze 

 Age, with the discovery of the many advantages of this alloy of 

 copper and tin. The Bronze Age extended approximately from 

 3000 to 1500 b.c. and shows gradual progression in the variety and 

 nicety of fabrication of tools, utensils, ornaments, etc., as well as 

 concomitant progress in many other aspects of human culture. It 

 eventually led to the Iron Age which bridges the transition be- 

 tween prehistoric and historic times. 



So Man has travelled far since culture emerged from the mere 

 biosocial pattern. He has gained an increment in each generation 

 and passed it on by so-called ' social heredity ' until the cumulative 

 result is monumental. Witness the high order of endeavor and 

 social integration that has led Man not only to modern science and 

 art, but has created within him the aspirations and ideals that 

 make him unique in the world of life. It spells modern civilization 

 that, ideally at least, ministers to the health, wealth, and happiness 

 of mankind. 



It is important to note that cultural evolution has given to 

 humanity greatly increased powers, although the hereditary physi- 

 cal basis apparently has remained essentially the same since the 

 origin of Homo sapiens. Increased cultural complexity has de- 

 pended upon the intelligent use of structures and capacities already 

 present and not upon the evolution of new ones. Indeed, the rela- 



