PREFACE 



In writing this book we hope we have a 

 start at supplying the orientation of which 

 ecology, a subscience of biology, is in 

 need. The time seemed ripe for a group of 

 ecologists, approaching the science from 

 various points of view and with various 

 techniques, to attempt to gather together 

 fundamental concepts, supported in so far 

 as possible by well-verified evidence. Others 

 have accumulated many facts that we have 

 drawn upon freely, from both published 

 compilations and original research reports, 

 but our effort has been directed primarily 

 towards the presentation and documentation 

 of general ecological principles. We have 

 not been wholly successful. Many concepts 

 and principles of a future science of ecology 

 are only beginning to be recognized, and 

 many important ideas that will be taught 

 to future classes in biology have not yet 

 been conceived by the present generation 

 of ecologists. 



We hope that, as a result of our efiForts, 

 the general biologist may more easily grasp 

 the scope and implications of ecology and 

 that profitable lines of investigation will be 

 more readily apparent to interested stu- 

 dents. We are encouraged by remembering 

 the stimulus gained some years ago from 

 Elton's small books, in which he emphasized 

 ecological principles. 



From our point of view there is an ur- 

 gent demand for three different types of 

 books about ecology. On the one hand we 

 could well use an encyclopedic treatise of 

 present-day knowledge of the subject. In 

 distinct contrast, a brief statement of the 

 underlying principles would also be useful. 

 We felt that there was also a need for a 

 study of the underlving principles together 

 with a sampling of the evidence on which 

 they are based. This is the task we have 

 undertaken. So far as possible, no fact is 

 admitted to these pages for its own sake, 

 and although no general concept is stated 



without the presentation of evidence sup- 

 porting it, an attempt has been made to 

 give no more than the necessary minimum 

 of factual support. 



At one point we are immediately on the 

 defensive. In Umiting our discussion, at 

 least in certain chapters of the book, pri- 

 marily to the principles of animal ecology, 

 we appear to be recognizing a logical 

 dichotomy between ecological relations of 

 plants and of animals where none exists. 

 The decision not to extend our work to in- 

 clude the whole scope of ecology, the so- 

 called bio-ecology of some writers, was 

 based primarily on convenience and work- 

 ability. Yet, although this book stresses ani- 

 mal ecology, we have felt free, in fact we 

 have been compelled, to draw on ideas from 

 plant ecology and to make continued use of 

 the concepts in which plants and animals 

 are necessarily considered together. The dis- 

 tinction between our "animal ecology" and 

 ecology in the most comprehensive sense 

 lies in our emphasis on the animal factors. 



We stress ecological generalizations from 

 two vantage points. First, there are those 

 principles concerned with the functions or 

 physiology of contemporary individuals and 

 ecological assemblages of whatever rank. 

 Second, there are those ecological principles 

 concerned with organic evolution. We are 

 not interested in helping to continue the 

 separation between these two aspects of 

 ecology. Rather, our aim is to point out 

 their essential interrelation, and we hope we 

 may have depicted ecology in better per- 

 spective in this connection. 



In addition to attempting the correlation 

 of the shorter-term contemporary phenom- 

 ena with a longer-term evolutionary per- 

 spective, we have also been impressed by 

 the need for an historical approach to many 

 aspects of the subject. Besides the fairly full 

 section on ecological history, the historical 

 approach is frequently made elsewhere in 



