The Human LineTechnology Hand axes (Acheulean) 1.8 million years agoMajor Symmetrical teardrop hand axes show planning and skill. The design lasts over a million years. ▲ MattersSaveShareTrace roots Longest chain: The Big Bang → First stars ignite → Supernovae seed heavy elements → The Sun forms → Earth forms → First oceans → First life → Photosynthesis evolves → Great Oxidation Event → Complex cells (eukaryotes) → Multicellular life → First animals → Cambrian Explosion → First vertebrates → Jawed fish → Fish walk onto land → The amniotic egg → The Great Dying → Dinosaurs appear → Asteroid ends the dinosaurs → Early primates → Apes split from monkeys → Human line splits from chimpanzees → Walking upright → First stone tools → Genus Homo appears → Homo erectus → Hand axes (Acheulean) Community notesLoading notes… Learn more ranked by votesDocumentnature.comAn earlier origin for the Acheulian (Lepre et al., Nature 2011) ↗Editor's pickDocumenthumanorigins.si.eduEarly Stone Age tools (Smithsonian Human Origins) ↗Editor's pickBookJohn J. SheaStone Tools in Human Evolution ↗Editor's pickVideoSearch on YouTubeAcheulean hand axe explained ↗Editor's pick