| ERA | PERIOD | EPOCH | M. yrs b.p. | LIFE FORMS APPEARING |
| THE AGE OF MAMMALS
(CENOZOIC): (Chapter 2) |
Quaternary | Pleistocene | 1.8-0.1 | Appearance and dominance of humans |
| Tertiary | Pliocene | 5-1.8 | Dominance of mammals, birds | |
| Miocene | 23-5 | Bony fishes | ||
| Oligocene | 38-23 | Rise of modern mammals | ||
| Eocene | 54-38 | Modern invertebrates | ||
| Paleocene | 65-54 | Primitive mammals | ||
| Mass extinction | ||||
| THE AGE OF REPTILES (MESOZOIC) | Cretaceous | 146-65 | Flowering plants | |
| Jurassic | 208-146 | Dinosaurs dominant | ||
| Mass extinction | ||||
| Triassic | 245-208 | First birds and mammals
First dinosaurs Early bony fishes Conifers |
||
| Mass extinction | ||||
| THE
DAWN OF LIFE (PALEOZOIC) |
Permian | 286-245 | Early reptiles | |
| Carboniferous1 | 360-286 | Giant insects Large amphibians Primitive plants |
||
| Mass extinction | ||||
| Devonian | 410-360 | Primitive fishes
Primitive plants |
||
| Silurian | 440-410 | Backboned animals | ||
| Mass extinction | ||||
| Ordovician | 505-440 | Invertebrates dominant | ||
| Cambrian | 544-505 | |||
| PRE-CAMBRIAN | 1,800 | Origin of Multicellular organisms | ||
| 2,000 | Origin of Eukaryotes | |||
| 3,800 | Origin of Prokaryotes | |||
| 5,000 | Formation of Earth | |||
| 1The Carboniferous is sometimes divided into an earlier Mississippian period and a later Pennsylvanian period. Main source: Museum of Paleontology at the University of California at Berkeley | ||||