Abstract

This thesis aims to advance evolutionary and epistemological knowledge of Middle and Late Pleistocene paleoanthropology, focusing on four main processes at the basis of cutting-edge research on modern human origins and evolution. These are the speciation of Homo sapiens, the transition to behavioural modernity, admixture with archaic hominin species outside Africa and human niche construction and global range expansion, here approached from the perspective of the current climate crisis. First, an extended single-origin of Homo sapiens will be defended on evidential and evolutionary grounds, arguing that the paleoclimatic and paleoenvironmental context of Middle Pleistocene Africa likely favoured an allopatric speciation process from a widespread and diversified ancestral population. Then the thesis will move to the behavioural and archaeological side of the origin problem. I will analyse the evolution of the research agenda on “behavioural modernity”, developing a philosophical account of “investigative disintegration” and criticizing Rubicon-based approaches that have not kept up with new standards of explanatory adequacy. I will then turn to paleogenomic research and discuss evidence of archaic admixture with respect to the taxonomic status of Homo sapiens and Neanderthals. I will approach the apparent conflict between molecular and morphology-based taxonomies from a diachronic perspective on lineage divergence and from an integrative perspective on different species conceptions and delimitation criteria, justifying distinct specific status on such grounds. Finally, I will frame anthropogenically-driven climate change as a niche construction process played at a global scale, having deep roots in Homo sapiens evolutionary history and long-term consequences that today require a counteractive response to prior actions to deviate from a potential evolutionary trap.