MAN 251 



they must have learned to use weapons and thus to kill prey more 

 easily, first using rough stone implements for this purpose. As 

 men became more civilized, they used implements of bronze and 

 of iron. About this time the subjugation and domestication of 

 animals began to take place. Men also began to cultivate the 

 fields and to have fixed places of abode. The beginnings of civili- 

 zation were long ago, but even to-day mankind is not entirely 

 civilized. 



The Races of Man. — At the present time there exist upon the 

 earth fiv§ races or varieties of man, each very different from the 

 others in instincts, social customs, and, to an extent, in structure. 

 These are the Ethiopian or negro type, originating in Africa ; the 

 Malay or brown race, from the islands of the Pacific ; the Ameri- 

 can Indian ; the Mongolian or yellow race, including the natives of 

 China, Japan, and the Eskimos ; and finally the Caucasians, 

 including the white inhabitants of Europe and America and the 

 Hindus and Arabs of Asia. 



Summary. — Plants and animals may be classified into species, 

 genera, families, orders, classes, and phyla. All classification is 

 based on homologies or likenesses in structure and position of 

 organs. Increasing complexity of structure is used as a basis for 

 the arrangement of plants and animals in series. A comparison 

 of such a series as is given in the preceding pages with fossils shows 

 us that the older the rocks, the more simple are the animal and 

 plant forms found in them. The fossils of complex forms are 

 found only in the later rocks. As respects civilization, the races 

 of mankind were once not so highly developed as they are now. 

 But even now many races are very backward and not entirely 

 civilized. 



Pboblem Questions 



1. Why are plants and animals classified? 



2. What is the basis for classification ? 



3. About how many species of plants are there ? About how many species 

 of animals ? 



4. Why are the insects such a large group ? 



5. Why is homology a basis for classification ? 



6. Could something be analogous without being homologous, or homologous 

 without being analogous? Give examples. 



7. What reasons have we for placing man as the highest animal? 



