Preface 



In the past it has generally been true that studies in comparative 

 physiology have been made either by Mammalian Physiologists 

 interested to find convenient animals in which to investigate 

 particular physiological mechanisms, or by Zoologists wishing 

 to extend their knowledge of animal structure, evolution, and 

 adaptation by investigating function. Nowadays increasing 

 numbers of biologists learn both Physiology and Zoology and 

 hence the synthesis of these two approaches has become increas- 

 ingly common at the university level and is rapidly becoming 

 more important in school biology teaching. As a consequence 

 such borderline subjects as 'Physiological Ecology' and 'Physio- 

 logical Genetics' have come into being, but 'Functional 

 Morphology' remains a basic element. In its broadest context 

 this involves a knowledge of classical comparative anatomy, 

 ecology, evolution, physiology and biochemistry. The amal- 

 gamation of parts from all these disciplines is an enormous task 

 but it is one in which Zoologists hold a central position. It is 

 hoped that this small book will indicate the nature of such a 

 broad-based approach in which the focal point remains the 

 animal in its environment and its evolution. 



One general feature of the comparative approach— to 

 anatomy or physiology — is that it is based upon a serial con- 

 sideration of individual organ systems. This sometimes gives 

 rise to the misconception that physiologists are concerned only 

 with parts of living organisms. But nothing could be further 

 from the truth, for a diagnostic character of the physiological 

 approach is the stress on integration, not only within each 

 functional system but between them. 



