Glossary of Organisms

The earliest group of fish with jaws, ranging from the Silurian to the Permian

Organic-walled microfossils common throughout the Proterozoic and early Paleozoic

A transitional group of vertebrates between fish and reptiles, capable of living on land, but returning to the water to reproduce
Geologic Range: Devonian to Recent

The first reef-buiders dominant from the Middle to Late Cambrian
Geologic Range: Early to Late Cambrian

A group of clam-like marine invertebrates separated into the Articulata and the Inarticulata based on shell morphology
Geologic Range: Cambrian to Recent

Microscopic tooth-shaped parts of an eel-like swimming vertebrate distantly related to modern chordates
Geologic Range: Cambrian to Triassic

Click here to view Mass Extinctions of the Phanerozoic Menu

Click here to view the Main Menu