ADAPTATIONS IN PLANTS AND ANIMALS 19 



As we go northward it is still more evident that temperature plays 

 an important part in determining the kind and amount of plant 

 growth. A glance at the picture will show this. The factors of the 

 environment evidently determine the kind of life to be found in a 

 given locality. If, for example, temperate forms of life were intro- 

 duced by man into the tropics, they would either die or gradually 

 change so as to become fitted to live in their new environment. 

 English sheep with long wool soon died when removed to Cuba, 













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Photo Galloway 



Vegetation in northern Alaska, where no trees grow. The reindeer feed 

 on grasses and lichens. 



where the climate is very warm. They were not fitted or adapted 

 to live in their changed environment. 



Adaptations. — Not only are plants and animals fitted to live 

 under certain conditions, but each part of the body may be fitted 

 to do certain work. I notice that as I write these words the fingers 

 of my right hand grasp the pen firmly and the hand and arm exe- 

 cute some very complicated movements. This they are able to 

 do because of the free movement given through the arrangement 

 of the delicate bones of the wrist and fingers, their attachment 

 to the bones of the arm, a wonderful complex of muscles which 

 move the bones, and a directing nervous system which plans the 

 work. Because of the peculiar fitnesses in the structure of the 



