| Era |
Period |
Epoch |
Million Years Ago (MYA) |
Characteristic Life |
| Cenozoic |
Quaternary |
Holocene (Recent) |
.001 |
Culmination of mountain building followed by erosion and moderate, short-lived invasions of continental margins by the seas. Rise of modern plants, animals, and man. Evolution of humans during the last 5-8 million years. Transition from archaic mammals to modern orders and eventually families. Early warming trends were reversed by the middle of the period to cooler and finally to glacial conditions. |
| Pleistocene |
1.8 |
| Tertiary |
Pliocene |
5.3 |
| Miocene |
23.7 |
| Oligocene |
36.6 |
| Eocene |
57.8 |
| Paleocene |
66.4 |
| Mesozoic |
Cretaceous |
|
144 |
Extensive mountain building at the end, climate cooled worldwide. Extinction of archaic birds and many reptiles by the end of this period. |
| Jurassic |
208 |
First reptilian birds. Reptilian diversity was high in all habitats. Climate was warm and stable with little seasonal variation. |
| Triassic |
245 |
Earliest dinosaurs, flying reptiles, marine reptiles. Primitive mammals appeared. Continents were high with few shallow seas. Climate warm. |
| Paleozoic |
Permian |
|
286 |
Rise of primitive reptiles. Extinction of the trilobites. Climate was cold at the beginning but warmed progressively. Widespread extinctions at the end of this period. |
| Pennsylvanian |
330 |
Earliest know insects, large arthropods. Climate generally warm and humid. Extensive coal producing swamps. Many specialized amphibians and the first appearance of reptiles. |
| Mississippian |
360 |
Extinction of some fish lineages expansion of others. Beginning of large coal production swamps. Extensive radiation of amphibians. |
| Devonian |
408 |
Explosion of fish and disappearance of many jawless varieties. First winged insects and tetrapods. Land was higher climate cooler. |
| Silurian |
438 |
Earliest know land animals. Primitive plants. Rise of fishes. Abundant trilobites. |
| Ordovician |
505 |
Earliest know vertebrates. Primitive plants. Trilobites and cephalopods abundant. |
| Cambrian |
550-590 |
Extensive shallow seas. Brachiopods and trilobites common. |
Precambrian |
Proterozoic |
|
2,500 |
Primitive water dwelling plants and animals. Changes in the lithosphere produced major land masses and shallow seas. |
| Archean |
4,600 |
Oldest know life (mostly indirect evidence). Formation of the earth and slow development of the lithosphere, hydrosphere and atmosphere. Development of life in the hydrosphere. |
Adapted from Pough, F. H. 1996. Vertebrate life, 4thed. Prentice Hall. Upper Saddle River, NJ.
Chart created by Arnold C. Mendez Sr. |
