Principles of Animal Ecology [antikvár]

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 vidth 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 efforts, the general biologist may more easily grasp the scope and implications of ecology and that profitable hnes of investigation will be more readily apparent to interested students. 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 urgent 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 underlying 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 supporting 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 limiting our discussion, at least in certain chapters of the book, primarily 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 include the whole scope of ecology, the so-called bio-ecology of some writers, was based primarily on convenience and workability. Yet, although this book stresses animal 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 distinction between our "animal ecology" and ecology in the most comprehensive sense Hes 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 perspective in this connection. In addition to attempting the correlation of the shorter-term contemporary phenomena with a longer-term evolutionary perspective, 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 ya