| Eon
| Era
| Period
| Epoch
| MYA
| Age of
|
| Phanerozoic
| Cenozoic
| Quaternary
| Holocene
| 0-2
| Mammals
| First humans
|
| Pleistocene
|
| Tertiary
| Neogene
| Pliocene
| 2-5
|
| Miocene
| 5-24
|
| Paleogene
| Oligocene
| 24-37
|
| Eocene
| 37-58
|
| Paleocene
| 58-66
| Extinction of dinosaurs, ammonites
|
| Mesozoic
| Cretaceous
| 66-144
| Reptiles
| First flowering plants
|
| Jurassic
| 144-208
| First birds, mammals
|
| Triassic
| 208-245
| First dinosaurs
|
| Paleozoic
| Permian
| 245-286
| Amphibians
| Extinction of trilobites
|
| Carboniferous
| Pennsylvanian
| 286-320
| First reptiles
|
| Mississippian
| 320-360
| Crinoids peak, sharks radiate
|
| Devonian
| 360-408
| Fishes
| First amphibians
|
| Silurian
| 408-438
| First land plants, ammonites
|
| Ordovician
| 438-505
| Invertebrates
| First fish, cephalopods dominant
|
| Cambrian
| 505-570
| First shells, trilobites dominant
|
| Proterozoic
| (Also known as Precambrian)
| 570-2,500
| First multicelled organisms
|
| Archean
| 2,500-3,800
| First one-celled organisms
|
| Hadean
| 3,800-4,600
| Approx age of oldest rocks 3,800 MY
|
Tucson Show Reports
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