Unlocking the hard tissue record of primate adaptability to environmental change

George Washington University, Washington DC

Investigators

Abstract

Modern humans have been able adapt to a diverse range of natural environments, and non-human primates can provide relevant models for understanding the evolutionary origins of this adaptive versatility in humans. This project will investigate variability in growth patterns and diet in response to early life environments, using climate, behavioral, and skeletal data for savanna baboons. The research will advance knowledge about relationships between life history flexibility and environmental variability in the human and non-human primate evolutionary record. The project also will support broader participation of underrepresented groups in STEM research, student mentoring and training, and public engagement through Smithsonian Institution programs and exhibits. Infrastructure for research and education will be enhanced by establishing the first available skeletal collection representing primates from a well-documented savannah habitat, thought to have been an important environment shaping early human adaptation. Results from the study will be communicated online, and to local wildlife managers. Key questions in biological anthropology concern the role that environmental variability played in shaping modern human behavior and life history, which increases fertility and maximizes offspring investment over a prolonged juvenile dependency. Developmental plasticity, including the capacity to respond to environmental change through shifts in growth rates, maturational timing, and other traits, is a proposed mechanism underlying the modern human life history strategy. However, the evolutionary origins and ecological context of life history flexibility in the human lineage remain poorly understood. This project integrates long-term climate data with developmental, behavioral and ecological data in wild baboons from a single, highly dynamic environment in the Amboseli basin, Kenya, to test how early life physical and social/maternal environments influence (1) hard tissue microanatomical parameters of dental and body size development, and (2) tooth carbon and nitrogen stable isotope signatures of diet quality and composition. Specifically, this research investigates whether offspring born into low rainfall and poor maternal/social environments experience negative consequences that are detectable in hard tissues, including lower quality diets, reduced investment in physical growth, and increased susceptibility to later-life stress. Elucidating how early environmental challenges in Amboseli baboons are mediated by developmental and behavioral mechanisms will improve understanding of this species' resilience despite significant environmental change. Further, by contributing a framework for deciphering the proximate ecological context of life history variation in hard tissues, this research has transformative potential for investigating relationships between adaptive versatility and environmental change during human evolution.