Tree of life By mark.song 4500 BCE Earth and solar system formed Period: 4500 BCE to 2000 BCE Archaeozonic 3700 BCE Bacteria 3400 BCE Anaerobic atmosphere formed 3300 BCE Single-celled organisms with a nucleus 2300 BCE Oxygen rich atmosphere formed Period: 2000 BCE to 600 BCE Protorezoic 1100 BCE Multi cellular organisms 600 BCE Worms Period: 600 BCE to 230 BCE Palaeozonic 550 BCE Crustaceans 400 BCE Fungi 400 BCE Marine vertebrates 400 BCE Pangaea formed 370 BCE Land Plants 350 BCE Insects 350 BCE Land vertebrates 300 BCE Pangaea moving apart Period: 250 BCE to 75 BCE Mesozoic 200 BCE South America separates from South Africa 150 BCE Seed plants 150 BCE Birds 75 BCE Primates Period: 75 BCE to 1 BCE Cainozoic