1. Hadean eon formation of the solar system
2. Archean eon buildup of oxygen; first eukaryotes
3. Proterozoic eon largest mass extinction in Earth's history
4. Phanerozoic eon time of the dinosaurs
5. Paleozoic era sometimes called "Age of Mammals"
6. Mesozoic era current eon in Earth's history
7. Cenozoic era toxic atmosphere; first bacteria
1.Hadean eonsometimes called Age of Mammals 2.Archean eontoxic atmosphere; first bacteria 3.Proterozoic eonbuildup of oxygen first eukaryotes 4.Phanerozoic eoncurrent eon 5.Paleozoic eratime of the dinosaurs 6.Mesozoic eralargest mass extinction in Earth's history 7.Cenozoic eraformation of the solar system