276 HOW DO WE CLASSIFY ANIMALS? 



America as there are between those same Bushmen and some of 

 the early races of man. Undoubtedly there once lived upon the 

 earth races of men who were much lower in their mental organi- 

 zation than are the present inhabitants. If we follow the early 

 history of man upon the earth, we find that at first he must have 

 been little better than one of the higher vertebrates. He was a 

 nomad, wandering from place to place, living upon whatever ani- 

 mals he could kill with his hands and whatever edible plants he 

 found. Gradually, he learned to use weapons to kill his prey, 

 first using rough stone implements for this purpose. As man be- 

 came more civilized, implements of bronze and of iron were used. 

 About this time the subjugation and domestication of animals 

 began to take place. Man then began to cultivate the fields, 

 and to have a fixed place of abode other than a cave. The be- 

 ginnings of civilization were long ago, but even today the world 

 is not entirely civilized. 



Demonstration. The skeleton of man compared with other mam- 

 mals. Use skeletons of a fish, frog, bird, dog or cat, and man. If 

 this material is not available in school, visit a museum. Observe the 

 kinds and places of the different bones in body of each skeleton. In 

 what ways do the various skeletons agree ? How do they differ ? 



Why is man a mammal ? Although we know that man is sepa- 

 rated by a gap from all other animals by the power of speech, we 

 must ask where we are to place him structurally. If we attempt 

 to classify man, we see at once he must be grouped with the 

 vertebrate animals because of his possession of a vertebral column. 

 Evidently, too, he is a mammal, because the young are nourished 

 by milk secreted by the mother and because his body has at least 

 a partial covering of hair. Among the different orders of mammals 

 man most closely resembles anatomically the primates to which 

 the monkeys and apes belong. 



If we compare several skeletons of different mammals, we 

 find certain definite likenesses in body plan. In the first place, 

 all vertebrates have the same general parts of the skeleton : the 

 skull, vertebral column, the front and rear appendages, and the 

 bony girdles, pectoral (shoulder) and pelvic (hip), which connect 

 the appendages with the main or axial skeleton. Then, too, they 



