The hypotheses on the origin of Homo sapiens are always of great interest. The last significant contribution to the theme is provided by the paper entitled Pan-Africanism vs single ‐ origin of Homo sapiens: putting the debate in the light of evolutionary biology, published in the journal Evolutionary Anthropology and signed by Giorgio Manzi, paleoanthropologist of the Department of Environmental Biology of Sapienza, and two colleagues from the University of Padua, the philosopher of science Andra Meneganzin and the historian and philosopher of biology Telmo Pievani. The authors examine the two most accredited hypotheses at present, analysing the lines of evidence supporting the models under discussion and highlighting some inferential limits and terminological misunderstandings recurring in the current international debate.

Having overcome the theories of the 1980s on the widespread origins of the modern human species, two visions are opposed today. The first, which is based on fossil evidence and genetic data, points out that the origins of Homo sapiens are to be found in an isolated population of East Africa over 200,000 years ago. The second, called "pan-African", suggests that the combination of characters typical of our species would have been acquired in different populations spread over a vast territory between Morocco and South Africa; from the influence of the genetic and cultural relationships constituted by these populations, in more remote times than those previously hypothesised (dating back to more than 300,000 years ago), the characteristics of the species would have emerged.

Giorgio Manzi, Andra Meneganzin and Telmo Pievani recognise speciation in isolated populations as the privileged modality for the origin of a new biological model, particularly during phases of marked environmental instability such as the one that occurred around 200,000 years ago, period to which are reported the oldest human skulls of globular shape coming from East Africa (Ethiopia). Their reasoning is based on a crucial human characteristic: the acquisition of a globular braincase, a feature that would result from a "punctuated" event of speciation starting from a small, isolated population.

The study thus suggests that this fundamental contribution may have emerged from a single population, although it is recognised that the pan-African model well describes the mosaic diversification of archaic human populations of the late Middle Pleistocene. "Nothing excludes - explains Giorgio Manzi - that there may have been, both before and after, an intense gene flow among African populations: at an intraspecific level, before speciation, and interspecific, after speciation, similar to the hybridisations that occur subsequently in Eurasia with the Neanderthals and the Denisovans. It is enough to admit that this may also have happened in Africa, between the first populations of the new species (Homo sapiens) and those of the mother species (Homo heidelbergensis)".

Riferimenti:

Pan‐Africanism vs. single‐origin of Homo sapiens: putting the debate in the light of evolutionary biology - Andra Meneganzin, Telmo Pievani, Giorgio Manzi - Evolutionary Anthropology (2022) https://doi.org/10.1002/evan.21955

Further Information 

Giorgio Manzi
Department of Environmental Biology
giorgio.manzi@uniroma1.it