It is with sadness that the Program in Human Biology shares the news that Paul R. Ehrlich, a founder of HumBio and Emeritus Bing Professor of Population Studies, died on Friday, March 13, 2026, at the age of 93.
Ehrlich was a widely known evolutionary ecologist and population biologist whose research, writing, and public engagement helped shape modern environmental thinking for more than half a century. He also developed the concept of coevolution with Peter H. Raven, describing how interacting species can evolve through reciprocal adaptations over time.
Over his 60-year tenure at Stanford, Ehrlich’s scholarship was grounded in the natural world, including influential research on butterfly populations and contributions to the fields of ecology, evolution, and population biology. He authored dozens of books for both scientific and public audiences, received wide recognition for his work, and remained deeply engaged in science communication throughout his life.
HumBio was one of the communities that benefited most directly from Ehrlich’s intellectual leadership and sense of purpose. At a time when interdisciplinary education was still emerging, he joined a small group of Stanford faculty who believed undergraduates needed a program that integrated biological, behavioral, social, and cultural perspectives to face the challenges of the modern world. That innovative founding vision remains central to HumBio today.
In the program’s early years, Ehrlich also played a direct role in shaping the Core curriculum. He taught HumBio 4A, Biology of Populations, for the first time during the 1970–71 academic year, and returned to teach it again in subsequent years, both independently and in collaboration with colleagues. He also taught the topic of extinction in HumBio 2B. Through his efforts, he helped establish the program’s emphasis on scientific rigor, big-picture thinking, and engagement with contemporary issues.
In an interview with Woods Institute Director Chris Field, Ehrlich shared that his two proudest life accomplishments were “protecting Jasper Ridge Biological Preserve and establishing the Human Biology program at Stanford” (Woods Institute news release, 2023).
Those who knew him remember a sharp intellect, a lively presence in conversation and debate, and a willingness to confront difficult questions directly. The Program in Human Biology owes a great deal to Professor Paul Ehrlich’s vision, leadership, and contributions at a formative moment in our history. His legacy endures in the program he helped build and in the generations of students and colleagues who carry forward its interdisciplinary vision.
Watch his 1987 HumBio 2B lecture on extinction and learn more about Ehrlich’s involvement in HumBio in this video interview and founders panel. Read the Stanford Report announcement.