Fossil

Fossils are preserved remains or traces of organisms from millions of years ago, found in rocks. They provide evidence of organisms that are no longer alive and allow scientists to compare life from different periods.

Fossils let scientists examine the bodies of extinct hominids and compare them with those of modern humans and other apes. A skull can give clues about brain size; the shape of leg, foot and hand bones can give clues about how an individual moved. Fossils of different ages show combinations of features that help scientists reconstruct changes over time.

Fossils provide a historical record extending over millions of years, whereas antibiotic resistance allows scientists to observe evolutionary change in bacterial populations over much shorter periods.

A fossil is evidence of an organism that lived in the past. It may preserve parts of its body, such as bones or a shell, or a trace it left behind. Plants can form fossils too.