PI

Julia Tejada

Assistant Professor of Geobiology - Division of Geological and Planetary Sciences

William Hurt Scholar

Affiliated faculty - Division of Biology and Biological Engineering

Julia Tejada is a paleobiologist and geochemist who studies how the chemistry of organisms records their ecology and physiology, and how those signatures can be used to reconstruct the evolution of life through deep time. Her research combines stable isotope geochemistry, organismal biology, and paleontology to investigate how diet, digestive physiology, and metabolism shape the chemical composition of animal tissues.

A major focus of the Tejada lab is developing new approaches based on the stable isotope composition of individual amino acids. Traditionally, these measurements have been used primarily to determine where organisms sit in a food web. Tejada's work asks whether they contain much richer biological information. Her lab is investigating how the isotope chemistry of amino acids, particularly threonine, records aspects of digestive physiology and dietary adaptation, with the goal of developing new tools for reconstructing animal ecology in both living and extinct species.

Julia's research also takes her into the field, particularly the western Amazon, where she and her collaborators recover fossil plants and vertebrates from understudied deposits. By combining discoveries from the fossil record with new geochemical approaches, her lab seeks to understand how organisms and ecosystems have changed across evolutionary time.

Julia received her undergraduate degree from Universidad Nacional Mayor de San Marcos in Peru, an MSc from the University of Florida, and an MA, MPhil, and PhD from Columbia University. She completed postdoctoral appointments at the University of Montpellier (France) and the University of Cambridge (UK) before joining the Caltech faculty in 2023.