Trends in Ecology and Evolution

Opinion Rethinking the ecological drivers of hominin evolution

A central goal of paleoanthropology is understanding the role of ecological change in hominin evolution. Over the past several decades researchers have expanded the hominin fossil record and assembled detailed late Cenozoic paleoclimatic, paleoenvironmental, and paleoecological archives. However, effective use of these data is precluded by the limitations of pattern-matching strategies for inferring causal relationships between ecological and evolutionary change. We examine several obstacles that have hindered progress, and highlight recent research that is addressing them by (i) confronting an incomplete fossil record, (ii) contending with datasets spanning varied spatiotemporal scales, and (iii) using theoretical frameworks to build stronger inferences. Expanding on this work promises to transform challenges into opportunities and set the stage for a new phase of paleoanthropological research.

Challenges and progress in hominin paleoecology

Hominin paleoecology seeks to understand the relationships between the evolutionary history of fossil hominins and the ecosystems in which they lived. Key questions include: (i) was global-scale climate change a major driving force in hominin diversification? (ii) Did paleoenvironmental dynamics influence hominin morphological and behavioral adaptations? (iii) Were changes in community structure and biotic interactions important in shaping hominin evolution and extinction? Attempts to answer these questions have fueled the recovery of paleoclimatic, paleoenvironmental, and paleoecological records, and the development of sophisticated analytical tools, but this progress has not always led to a deeper understanding of hominin evolution. This stems from the limitations of research strategies that focus on linking temporal patterns of ecological change with milestones in hominin evolution - such as speciation and extinction events or shifts in hominin behavior - and inferring causal relationships between the two. How can hominin paleoecology move beyond this pattern-matching paradigm to generate enduring insights about the influence of ecological change on hominin evolution?

Capitalizing on the growing body of empirical data requires that hominin paleoecology rethinks its strategy for formulating research questions and how they are answered. We examine several theoretical and epistemological challenges that have long hindered the development of robust evolutionary insights, and highlight how recent research is addressing them. This work (i) confronts the limitations of an incomplete fossil record, (ii) contends with proxy records that span a considerable range of spatiotemporal scales, and (iii) uses theoretical frameworks that link ecology and evolution to build stronger inferences. Our goal is to highlight promising new research directions that move beyond inferences based on ecological and evolutionary pattern-matching to a deeper understanding of causality in hominin evolutionary history.