Deep TimeLife & Evolution End-Ordovician mass extinction 445 million years agoNotable A glaciation centered on Gondwana chilled the oceans and drained shallow seas. About 85 percent of marine species died out, the first of the five great mass extinctions. ▲ 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 → End-Ordovician mass extinction Community notesLoading notes… Learn more ranked by votesBookPeter BrannenThe Ends of the World ↗Editor's pickVideoSearch on YouTubeend Ordovician mass extinction explained ↗Editor's pick