THE STUDY OF ANIMALS AND THEIR LIFE 3 



things about its relations to the outer world, and its special 

 fitness for life. 



All that is known of these different kinds of facts about 

 the dog constitutes our knowledge of the dog and its life. 

 All that is known by scientific men and others of these 

 different kinds of facts about all the 500,000 or more kinds 

 of living animals, constitutes our knowledge of animals and 

 is the science zoology * Names have been given to these 

 different groups of facts about animals. The facts about 

 the bodily make-up or structure of animals constitute that 

 part of zoology called animal anatomy or morpJiology; the 

 facts about the things animals do, or the functions of 

 animals, compose animal physiology; the facts about the 

 development of animals from young to adult condition are 

 the facts of animal development; the knowledge of the 

 different kinds of animals and their relationships to each 

 other is called systematic zoology or animal classification; 

 and finally the knowledge of the relations of animals to 

 their external surroundings, including the inorganic world, 

 plants and other animals, is called animal ecology. 



Any study of animals and their life, that is, of zoology, 

 may include all or any of these parts of zoology. Most 

 zoologists do, indeed, devote their principal attention to 

 some one group of facts about animals and are accordingly 

 spoken of as anatomists, or physiologists, systematists, 

 and so on. But such a specialization of study should be 

 made only after the zoologist has acquired a knowledge 

 of the principal or fundamental facts in all the other 

 branches of zoology. 



A first course in zoology. The first " course," then, 

 in the study of animals should include the fundamental 

 facts in all these branches or parts of zoology. That is 

 what the course outlined in this book tries to cover. 



* Zoology is formed from two Greek words: zoon, meaning animal, and 

 logos, meaning discourse. 



