World Prehistory: Human Origins and the Peopling of the Globe

The archaeological record of human origins begins in East and Southern Africa, where fossil finds spanning over six million years — from early bipedal hominins like Sahelanthropus and Australopithecus afarensis ('Lucy', discovered by Donald Johanson in 1974 at Hadar, Ethiopia) to early Homo — document a long process of bipedalism, brain enlargement, and stone tool manufacture preceding the appearance of anatomically modern Homo sapiens roughly 300,000 years ago, as revised upward by finds at Jebel Irhoud in Morocco in 2017. The 'Out of Africa' model, now strongly supported by mitochondrial DNA and whole-genome studies pioneered by Rebecca Cann, Allan Wilson, and later Svante Pääbo's ancient DNA work, holds that all present-day non-African human populations descend from a relatively small group that left Africa within roughly the last 70,000-60,000 years, though earlier, ultimately unsuccessful dispersals occurred tens of thousands of years before that.

The archaeological signature of this dispersal is written in stone-tool traditions and, increasingly, ancient DNA extracted directly from fossil bone. Homo sapiens' spread into Southwest Asia and onward into South Asia by around 60,000-70,000 years ago is documented at sites across the Arabian Peninsula and the Indian subcontinent; into Europe by around 45,000 years ago, where they overlapped and interbred with Neanderthals, leaving a genetic signature of roughly 1-2% Neanderthal DNA in most non-African populations today, a discovery made possible by Svante Pääbo's sequencing of the Neanderthal genome, for which he received the 2022 Nobel Prize; and into Sahul (Australia-New Guinea) by at least 65,000 years ago via a still-debated maritime or island-hopping route, evidenced at sites like Madjedbebe rock shelter in Arnhem Land.

The peopling of the Americas remains one of the most actively revised chapters in world prehistory. The long-dominant 'Clovis-first' model, which held that big-game-hunting populations entered the Americas via the Bering land bridge (Beringia) and an ice-free corridor around 13,000 years ago, has been overturned by sites such as Monte Verde in Chile (dated to at least 14,500 years ago) and increasingly by pre-Clovis evidence across both continents, alongside genetic and coastal-geomorphological evidence supporting a 'coastal migration' route down the Pacific rim that would have been available thousands of years earlier than an interior ice-free corridor.

Comparative world prehistory also illuminates the independent, near-simultaneous emergence of agriculture in multiple 'hearths' after roughly 10,000 BCE — the Fertile Crescent (wheat, barley, sheep, goats), China (rice in the Yangzi valley, millet in the Yellow River valley), Mesoamerica (maize, beans, squash), the Andes (potatoes, quinoa, llamas), and separately in parts of Africa and New Guinea — a pattern that led Jared Diamond and others to ask why some regions' domesticable plant and animal packages proved far more productive and expansive than others, with lasting consequences for the relative power of Eurasian versus other world civilisations that Diamond controversially attributes substantially to geography and biogeography in Guns, Germs, and Steel.

World prehistory as a field therefore integrates palaeoanthropology, archaeology, genetics, and linguistics into a single evidentiary conversation, and it continues to be revised rapidly: new dates from sites like White Sands, New Mexico (footprints potentially 21,000-23,000 years old) and new ancient-DNA studies routinely push back or complicate previously settled dispersal chronologies, making this one of the most dynamic areas of the discipline.