Rethinking the ecological drivers of hominin evolution
Authors: J. Tyler Faith, Andrew Du, Anna K. Behrensmeyer, Benjamin Davies, David B. Patterson, John Rowan, Bernard Wood
Journal: Trends in Ecology & Evolution (2021)

Research aiming to understand the role of ecological change in hominin evolution has fueled the generation of paleoclimatic and paleoenvironmental records across Africa. Limitations of conventional methods for inferring ecology–evolution relationships mean that more data have not always led to a deeper understanding of hominin evolution. We outline several challenges that have hindered progress, and highlight how recent research is addressing them. This research is confronting the limitations of the fossil record, contending with proxy records spanning a range of spatiotemporal scales, and providing a stronger inferential approach to hypothesis testing. Addressing the obstacles that have hindered progress will enable a more robust understanding of the relationships between ecological change and 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. 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. molecular fossils (e.g., organic compounds) that are preserved in soils and sedimentary records, and which are indicative of past environments, climates, and fire regimes. in geology, a region of the Earth's surface where there is net accumulation of sedimentary deposits over time that may also preserve a fossil record. in geology, the physical environment in which sedimentary rocks are formed (e.g., floodplains, rivers, lakes, oceans) that are identified on the basis of lithofacies characteristics (e.g., sediment type and bedding structures). respectively, the oldest and youngest appearance of a taxon in the fossil record, which together define the observed temporal range of the taxon. These dates are frequently revised with new fossil discoveries. computer simulations illustrating the macroscale patterns that emerge through the microscale interactions of individual system components over time. the macroscopic wear patterns on an animal's teeth that result from processing foods with different mechanical properties. the microscopic wear patterns on an animal's teeth that result from processing foods with different mechanical properties. observations based on natural systems. In taphonomy, for example, this refers to studies in which taphonomic processes (e.g., bone consumption by carnivores) are observed in the absence of experimental manipulation. also known as Milankovitch cycles, these are cyclical variations in Earth;'s orbit (eccentricity, precession, obliquity) that drive climate change over geological timescales. CaCO3 precipitated during soil formation, usually in seasonally dry environments. They record carbon and oxygen isotope ratios that reflect the dominant vegetation or soil water system dynamics (e.g., evaporation), respectively. the spatial and temporal scales over which a process or phenomenon occurs. In hominin paleoecology, spatial extents often range from local to continental, and temporal extents from several years to millions of years. the study of the processes involved in the formation of the fossil record (e.g., death, decay, scavenging, burial, mineralization), and how these processes affect the information preserved in fossil samples of past life. the number of species in a biotic community; in the context of the hominin clade, this refers to evidence that it included more than one species at any given time. the outcome of geological and taphonomic processes that control how much time is represented in a fossil assemblage (taphonomic time-averaging), or analytical decisions concerning how to aggregate fossil samples from different stratigraphic horizons or localities (analytical time-averaging). a change in species composition through time as a result of speciation, extinction, and dispersal. a model of macroevolutionary change developed by Elisabeth S. Vrba by which climate-driven changes in habitats leads to a synchronous peak in turnover (extinction, speciation, and dispersal) across multiple lineages. Vrba applied this model to the African record, proposing that global cooling between 2.8 and 2.5 Ma led to a major turnover pulse that included the first appearance of Homo and Paranthropus [51.Vrba E.S. The fossil record of African antelopes (Mammalia, Bovidae) in relation to human evolution and paleoclimate.in: Vrba E.S. Paleoclimate and Evolution with Emphasis on Human Origins. Yale University Press, 1995: 385-424Google Scholar,68.Vrba E.S. Mammals as a key to evolutionary theory.J. Mammal. 1992; 73: 1-28Crossref Scopus (277) Google Scholar].