The Pan-African Evolution Project

The Pan-African Evolution project is focused on understanding the early periods of human prehistory, and how early human shaping of the earth had cascading effects down to the present day. Specifically, the group explores three key themes:

• The emergence and expansion of the human niche, together with its technological, societal, and ecological feedbacks.
• Disease-culture co-evolution.
• Cultural and Technological Changes in Human History

Theme 1: Emergence and Adaptation of the Human Niche

A dominant view has purported that, since humans evolved in Africa, they lived in relative harmony with the plants and animals on the continent. Conversely, with the expansion beyond Africa, humans encountered novel environments and a naïve fauna, both of which they aggressively exploited. In the case of animals, this exploitation is thought to have driven the collapse of many species of megafauna whose extinction had wide-ranging implications for ecosystem resilience. However, this view reduces African ecosystem diversity to negligible levels and harks back to problematic tropes of the so-called "noble savage". While African megafauna have not died out, the way humans have impacted the distribution of different faunal communities has barely been explored – with implications for conservation and environmental restoration. At the same time, palaeoenvironmental reconstruction is revealing that many apparently pristine constellations of vegetation today are actually unusual, if not anomalous, suggesting human agency is at play. Widespread burning of landscapes may reach back to some 90 thousand years, allowing small hunter-gatherer populations to transform landscapes. These events are precursors to behaviors that began to catalyze the planetary-scale impacts of human behavior.

The Human Palaeosystems Group is seeking to understand the expansion of the human niche and its impacts in Africa in several ways. We are using an ecological niche model approach to:

• Test and refine paleoclimate models.
• Understand whether African fauna sharing the same niche as humans have been impacted over the last 120,000 years.
• Reconstruct changes in human niche space in the Pleistocene and document expansions.

Additionally, we are using paleoclimate models to explore the locations of possible human refugia in the Pleistocene to better develop a pan-African framework for archaeological and paleoanthropological investigation.

At the same time, primary data is also required to address these questions. Research now indicates that most of the African continent is implicated in the emergence of our species, Homo sapiens. However, vast swathes of the continent remain unexplored. Therefore, we are focusing on West Africa – a major continental region for which there is almost no data on human evolution and niche expansion. Our team is conducting fieldwork in Benin, Nigeria, Guinea, Senegal, and the Ivory Coast to document and obtain:

• A comprehensive database of early human sites in West Africa that are chronometrically dated, along with material culture and associated fauna.
• Documenting the presence of sites in diverse ecosystems (e.g., rainforest).
• Twinned paleoenvironmental proxy data to reconstruct the climate context of ancient human occupations in this region, including understanding fire regimes and changes therein.
• Ancient DNA and/or ancient proteomes to reconstruct changes in ancestry and population dynamics.

By combining the production of targeted primary data with modeling approaches, we will build a comprehensive picture of the emergence of our species and immediate impacts on the environment. In this way, we will gain a greater understanding of what pristine environments in Africa really mean and identify the feedbacks and legacies of niche expansion on human societies over long timescales, with lessons for the present – particularly for ecosystem restoration.

Postdocs: Dr James Blinkhorn, Dr Alex Blackwood, Dr Lucy Timbrell, Dr Eslem Ben-Arous

Theme 2: Disease-Culture Co-Evolution

A major impact of expansions in the human niche are the feedbacks on human health. Transformation of the environment through burning, the clearing of trees and adaptation to new biomes must also be understood through changes in the disease load for humans. To date, the demography of the first humans is very rarely understood through disease load, and is most typically explored only through climate variables. Yet diseases such as malaria and other tropical vector-borne diseases have been present for a long time, and likely drove changes in both human demography as well as culture. The impact of new diseases on human culture and our resilience to disease has most recently been brought into sharp focus through the COVID-19 pandemic.

We are building a malaria stability index to explore its relationship with the distribution of human groups in Pleistocene Africa, and possible impact on material culture features (e.g. the use of ochre, exploitation of particular plants, etc.). Vector genetic history will then be simulated using these data and matches with the true data will then be explored to refine understanding of disease impacts.

By developing a pipeline for this work, our research group will also be exploring a suite of tropical diseases in the same way, with the ultimate goal of mapping the Pleistocene disease burden on humans and the potential impact on (1) human biocultural evolution, and (2) the expansion of the human niche, with expecting feedbacks taking place between both of these.

Postdocs: Dr Margherita Colucci, Dr James Blinkhorn

Theme 3: Cultural and Technological Changes

The causes of the first efflorescences of human culture and the signatures of regional identity and culture are poorly understood. This is in part because stone tools, the most abundant source of data on human culture and behaviour for the bulk of human prehistory, lack reliable and replicable methods of analysis. We are both developing innovative and replicable methods of analysis, as well as collating large datasets of stone tools in order to explore the diversity of stone tools across Africa over time, and understand the covariance between stone tools and climate, ecology, carrying capacity, population size, density, and other factors. By understanding these relationships better, we will be able to recreate the rate of acceleration (or lack of it) of technological change, responses to shocks, and the basis of the technosphere.

Postdocs: Dr Lucy Timbrell