With its roots in organismal biology and motivated by questions about the distribution and abundance of organisms, mechanisms underlying evolutionary change, and relationships between functional traits and the environment, physiological ecology now finds itself at the center of some of the most important questions in ecology and human-environment interactions. This symposium will mark the 50th year of Physiological Ecology Section presentations at the annual meeting. While the discipline is still young, over the course of the past five decades, physiological ecologists have made many transformative contributions to our understanding of the living planet. Researchers tackle questions about the trajectory of the biosphere in the face of anthropogenic change, the diversification of life through evolutionary time, the potential limits of resilience in the anthropocene, and continue to push the boundaries of our understanding of mechanisms that drive specialization, plasticity, stress tolerance and species coexistence. Physiological ecologists work across a large range of spatiotemporal scales, from sub-cellular processes to the exchange of energy and materials at continental and global scales. This symposium will highlight exciting work being done across this range and communicate to the broader community a celebration of the discipline as we mark the passage of 50 years of annual research presentations to the Society.