Overview

The fossil record consists of approximately 3 to 3.5 Ga of fossils. Terrestrial organisms, such as ourselves, are present in only one seventh of that record. The period of particular interest for terrestrialization is the Devonian.

A Brief History of Time

Quarternary: From present to 1.6 Ma. Continents are configured in thier present day positions and climates are comparable to today.

Tertiary: From 1.6 Ma to 65 Ma. Large radiation of mammals after the extinction of the dinosaurs.

Cretaceous: From 65 Ma to 144 Ma. Appearance of the first marsupials.

Jurassic: From 144 Ma to 208 Ma. Appearance of the first birds.

Triassic: From 208 Ma to 245 Ma. First appearance of dinosaurs.

Permian: From 245 Ma to 286 Ma. Continents in Pangea configuration.

Pennsylvanian: From 286 Ma to 330 Ma. Appearance of first reptiles.

Mississippian: From 330 Ma to 360 Ma. Radiation of tetrapods.

Devonian: From 360 Ma to 408 Ma. Appearance of first amphibians, (first terrestrial vertebrates).

Silurian: 408 Ma to 438 Ma. First vascular plants.

Ordovician: From 438 Ma to 505 Ma. First jawless fish, (Agnatha).

Cambrian: From 505 Ma to 570 Ma. Cambrain "explosion " of life. All phylas established.

Proterozoic: From 2.5 Ga to 544 Ma. (*There is some debateover the actual placement of the boundry between the Proterozoic and the Cambrian, having to do with the ediacaran fauna of the time.) No fossil evidence.

Archean: From 2.5 Ga to 4.6 Ga. No fossil evidence.