Since then, conventional wisdom in human evolutionary studies has supposed that the origins of knapping stone tools by our ancestors – that is, chipping away flakes from a stone to make a tool – were linked to the emergence of the genus
Homo. The premise was that our lineage alone took the cognitive leap of hitting stones together to strike off sharp flakes, and that this was the foundation of our evolutionary success. Scientists thought this technological development was tied to climate change and the spread of savanna grasslands; our ancestors innovated with new tools to help them survive in an evolving landscape.
Over the last few decades, however, subsequent discoveries pushed back the date for the earliest
stone tools to 2.6 million years ago (Ma) and the earliest fossils attributable
to early Homo to only 2.4-2.3 Ma. By necessity, there’s been increasing openness to the possibility of tool manufacture before 2.6 Ma and by hominins other than
Homo.
A series of papers published in rapid succession in early 2015 have solidified these ideas into an emerging paradigm shift in paleoanthropology: the fossil record of the genus
Homo now
extends back to 2.8 Ma in the Ethiopian Afar;
cranial and
post-cranial diversity in early
Homo is much wider that previously thought, already evincing several distinct lineages by 2 Ma; and
Australopithecus africanus and other Pleistocene hominins, traditionally considered not to have made stone tools, have a
human-like trabecular bone pattern in their hand bones that’s consistent with tool use.
