Annex II: The Founder Lineage: Stabilization, Integration, and Emergence of Homo erectus

This annex develops the concept of a founder lineage as applied to Homo erectus, understanding its emergence not as a punctual origin but as the outcome of a stabilization process within a reorganizing evolutionary reticulation. Through an integrated analysis of Koobi Fora, Olduvai, and Dmanisi, it describes how the extreme diversity of the Africanus reticulation progressively contracts until producing a coherent functional state—anatomical, technical, and ecological—capable of expanding across continents without fragmenting. The text situates this process within the paleoenvironmental framework of the Early and Middle Pleistocene, including the role of the African gap as a phase of low fossil visibility associated with the Mid-Pleistocene Transition. Overall, the annex proposes a processual reading of the transition toward Homo erectus, where the key is not the appearance of a “first Homo” but the stabilization of an evolutionary system that inaugurates a new scale in human history.