Unity in diversity: A perspective on the methods, contributions, and future of comparative physiology

This brief essay on the methods, objectives, achievements, and future promi se of the discipline known as comparative physiology focuses on three princ iple issues. First, how is this discipline defined in terms of its approach es and goals? What does the adjective comparative denote, and what makes th e comparative approach unique? Second, what are illustrative examples of th e successes of the comparative method in the study of physiology? Why has t he comparative approach so often been critical in the development of basic understanding of physiological systems? Third, how is comparative physiolog y likely to contribute in the near future to the biological sciences, here broadly defined to include research ranging from study of the consequences of global change to the development of biomedical technology? And, converse ly, how are advances in other disciplines in biology likely to enhance comp arative physiology? I hope to demonstrate that comparative physiology is an essential complemen t to other disciplines within physiology that commonly exploit a relatively small number of so-called model organisms in attempts to elucidate basic m echanisms of physiological function. I argue that there exists a creative i nterplay between physiologists doing comparative work and others who carry out primarily reductionist studies with model species. Whereas the latter t ypes of studies offer the comparative physiologist many useful new techniqu es and insights into basic mechanisms, it is the comparative physiologist w ho often uncovers important new phenomena for investigation and who, throug h the logic of comparative analysis, elucidates key principles that might n ot emerge from the study of conventional model organisms.