2 INTRODUCTION 



cal sciences is ecology, the study of the relations of a group of organisms 

 to its environment, including both the physical factors and the other 

 forms of life which provide food or shelter for it, compete with it in 

 some way, or prey upon it. 



Some zoologists specialize in the study of one group of animals. 

 There are mammalogists, ornithologists, herpetologists and ichthyolo- 

 gists who study mammals, birds, reptiles and amphibians, and fishes, 

 respectively; entomologists, who investigate insects; protozoologists, who 

 study the single-celled animals, and so on. 



The science of zoology thus includes both a tremendous body of 

 facts and theories about animals and the means for learning more. The 

 ultimate source of each fact is in some carefully controlled observation 

 or experiment made by a zoologist. In earlier times, some scientists kept 

 their discoveries to themselves, but there is now a strong tradition that 

 scientific discoveries are public property and should be freely published. 

 In a scientific publication a man must do more than simply say that 

 he has made some particular discovery; he must give all of the relevant 

 details of the means by which the discovery was made so that others can 

 repeat the observation. It is this criterion of repeatability that makes 

 us accept a certain observation or experiment as representing a true 

 fact; observations that cannot be repeated by competent investigators 

 are discarded. 



When a scientist has made some new observation, or carried out a 

 series of experiments that add to our knowledge in a field, he writes a 

 report, called a "paper," in which he describes his methods in sufficient 

 detail so that another worker can repeat them, gives the results of his 

 observations, discusses the conclusions to be drawn from them, perhaps 

 formulates a theory to explain them or discusses how they are explained 

 by a previous theory, and finally indicates the place of these new facts 

 in their particular field of science. The knowledge that his discovery will 

 be subjected to the keen scrutiny of his colleagues is a strong stimulus 

 for repeating the observations or experiments carefully before publish- 

 ing them. He then submits his paper for publication in one of the 

 professional journals in the particular field of his discovery. There are 

 several thousand zoological journals published all over the world. Some 

 of the more important American ones are the Journal of Experimental 

 Zoology, Journal of Cellular and Comparative Physiology, Biological 

 Bulletiyi, Physiological Zoology, American Journal of Physiology, Ana- 

 tomical Record, Ecology and the journals devoted to research on a 

 particular group of animals, such as the Journal of Mammalogy. The 

 paper is read by one or more of the board of editors of the journal, all 

 of whom are experts in the field. If it is approved, it is published and 

 becomes part of "the literature" of the subject. 



At one time, when there were fewer journals, it might have been 

 possible for one man to read them each month as they appeared, but 

 this is obviously impossible now. Journals such as Biological Abstracts 

 assist the hard-pressed zoologist by publishing, classified by fields, very 

 short summaries or abstracts of each paper published, giving the facts 

 found, the conclusion reached, and an exact reference to the journal in 



