PART IV 



PRINCIPLES OF BIOLOGY APPLIED TO 

 HUMAN STRUCTURE AND LIFE 



368. Human Biology. Biology is the science of living 

 things, and human biology may be defined as the study of 

 man considered as a living thing and interpreted in the light 

 of studies of other living things. 



The justification for including study of man as part of 

 biology is found in the fact that the human body in its 

 structure and functions is remarkably like animals, the 

 higher forms in particular. In the body of man are the same 

 organs as in the animals known as beasts or mammals; 

 and the organs of man and the beasts are closely alike 

 even in microscopic details. This similarity also appears 

 when comparing man with still lower animals. In short, 

 when biologists consider the close similarity of structure and 

 function in man and various types of animals, they see no 

 escape from the conclusion that man's relation to the animal 

 kingdom is as stated in the next paragraph. 



369. The Classification of Man. (1) As suggested above, 

 man belongs to the animal kingdom, because his body is 

 built on the plan of structure found in many animals. 

 (2) Man is a backboned or vertebrate animal, because he pos- 

 sesses a backbone or vertebral column. (3) Man belongs to 

 the class of mammals or Mammalia,because he has the three 

 characteristics of this group, hair, diaphragm, and mam- 

 mary glands. (4) Man belongs to the order of the Primates, 

 because his body is in numerous respects more similar to apes 



455 



