Home > Encyclopedia of Science > Fossil and Fossilization

• Formation of fossils
• Words to Know
• The fossil clock

A fossil is the remains or traces of a once-living plant or animal that was preserved in rock or other material before the beginning of recorded history. The term also is used to describe the fossil fuels (oil, coal, petroleum, and natural gas) that have been formed from the remains of ancient plants and animals. It is unusual for complete organisms to be preserved. Fossils usually represent the hard parts, such as bones or shells of animals and leaves, seeds, or woody parts of plants. Fossils occur on every continent and on the ocean floor. Through paleontology (the scientific study of fossils), it is possible to reconstruct ancient communities of living organisms and to trace the evolution of species.

Fossils of single-celled organisms have been recovered from...