Getting Started with Paleontology

Paleontology is the scientific study of life in the geologic past, primarily through the analysis of fossils. While dinosaurs are the most famous subjects, paleontology covers all ancient life from microscopic bacteria to giant marine reptiles.

Dinosaurs first appeared during the Triassic Period, approximately 230 million years ago. They dominated terrestrial ecosystems for over 160 million years before the mass extinction event 66 million years ago. However, one lineage survived and thrives today: birds are living dinosaurs.

To understand dinosaurs, start with the two major orders: Saurischia (lizard-hipped) and Ornithischia (bird-hipped). Saurischia includes the meat-eating theropods and the giant long-necked sauropods. Ornithischia includes the armored ankylosaurs, plated stegosaurs, horned ceratopsians, and duck-billed hadrosaurs.

Fossils form through a process called permineralization, where mineral-rich groundwater replaces organic material with stone. The best preservation occurs when animals are quickly buried by sediment in river deltas, lake beds, or volcanic ash. Only a tiny fraction of all dinosaurs that ever lived became fossils.