Chapter 1: Animals and Environments: Function on the Ecological Stage

Animals and Environments: Function on the Ecological Stage then introduces the two central questions in physiology: the mechanisms of function and their evolutionary origins. The authors emphasize the integrative nature of physiology, spanning molecular biology, ecology, and evolutionary theory. The text explains the difference between regulators and conformers in response to environmental changes, introducing concepts such as homeostasis, negative feedback, and the energetic costs of maintaining internal constancy. The chapter details five time frames for physiological change—acute, chronic, evolutionary, developmental, and clock-controlled—and highlights how these time frames influence animal adaptation and survival. The discussion of scaling explains how body size profoundly affects physiological traits like gestation length, metabolic rate, and energy use. Environmental factors—especially temperature, oxygen availability, and water balance—are examined in depth, with examples ranging from heat-adapted desert iguanas to cold-tolerant Antarctic fish. The chapter closes with the concept of microenvironments and how animals actively shape their own conditions, setting the stage for understanding physiological ecology across all animal life.