I am interested in the evolution of physiological and morphological systems and in their adaptations to diverse environmental factors, particularly temperature. My research has examined organismal energetics, performance capacities, and thermoregulation and has attempted to uncover the functional bases of organism-level performance at both the enzymatic and systemic (e.g., muscular, circulatory) levels. Most of my research has concentrated on reptiles and amphibians, in which limited capacities of oxygen uptake and poikilothermy create interesting adaptive patterns in behavior and energy allocation that are quite distinct from those of endotherms. I have in addition done physiological research on fish, birds, and mammals. I also utilize bacteria to study the processes and consequences of both evolutionary and phenotypic adaptation to novel thermal environments. My current research projects include examinations of the plasticity of cardiopulmonary function in reptiles and the evolution of thermal and acidity adaptation in experimental evolutionary lineages of bacteria.