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THE CHANGING WORLD OF LIFE 



ears to pick up sounds more efficiently. Thousands of such examples 

 could be given to indicate relationships through anatomy. 



Evidence from Genetics. The ultimate basis for all evolutionary 

 changes must be genetic in nature, for changes in living things must be 

 inherited to have significance in altering the species. We have already 

 learned how gene mutations coupled with selection can result in evolu- 



Upper pictures, New York Zoological Society 

 Lower pictures, Chicago Natural History Museum 



Fig. 34.11. Evolution in the camels. When animals of the same type migrate to vary- 

 ing environmental conditions, they tend to develop differences in accordance to the 

 environment in which they live. The Bactrian camel at the upper left is found in 

 Central Asia where cold weather is encountered and has developed long shaggy hair 

 as a protection. The Dromedary or Arabian camel lives in desert regions and has 

 developed broad pads on its feet to give it traction on the sand and pouches in its 

 stomach to store water. The llama of South America at the lower left has followed 

 another line of development. The alpaca at lower right has developed a heavy shaggy 



coat as a protection against the cold. 



