This project examines the development and influence of human ecology, an interdisciplinary area of study that incorporated research from the life and human sciences and laid the intellectual foundations for environmental history, cultural geography, and cultural ecology, as well as for a deeper understanding of anthropogenic environmental change within the life sciences. I trace its roots beyond the well-known conservation movements and activist events of the 19th and 20th centuries and highlight the importance of Jean-Baptiste Lamarck and Charles Darwin, who in underscoring the continuity between humans and other life forms, influenced views on the natural world and humanity's place within it. I emphasize that their work also contributed to the development of ecology, which emerged as a cohesive area of science in the late 19th century and focused on the relationships among individual organisms, groups of organisms, and their environments, as well as on processes like adaptation and niche construction.

This study further explores how sociologists, historians, and anthropologists embraced ecological ideas in the 1920s and addressed what they perceived to be the artificial division between natural and human history erected by Western intellectual traditions. They used evolutionary theory and ecological ideas to reconceptualize the dynamic and reciprocal interactions between humans and their environments and to establish that humans were a part of the “web of life.” Additionally, by examining the contributions of key figures like Julian Steward and Carl Sauer, the project illustrates how human ecologists collaborated with biological scientists to craft novel research and insights. This interdisciplinary approach was exemplified in events like the 1955 conference "Man’s Role in Changing the Face of the Earth," which brought together ecologists, zoologists, and anthropologists to address critical environmental issues. I also examine how Steward, Sauer, and others were inspired by the French Annales school, Paul Vidal de la Blache, Radhakamal Mukerjee, Alexander von Humboldt, and Goethe, and I explore how human ecologists applied and refashioned some of the contributions of these earlier scholars. This research project also aims to highlight that the relationship between biological and social thought has not always been unidirectional, and it suggests that some of the origins of persistent debates within environmentally oriented human and biological sciences can be seen within research on human ecology. These include discussions about the threshold for environmental change, debates about the promises and perils of interdisciplinary research, and questions about the extent to which environmental fields should be anthropo- or ecocentric.