Paleontology is the science of fossils: ancient bones, shells, plants, and other traces of life preserved in rock. It asks what lived on Earth long ago, how those living things were built, and how life changed over a huge stretch of time. Dinosaurs made the subject famous, but the field is much wider — early fish, forests, tiny ocean life. It sits near geology (rocks and time) and biology (living things), though actually it is its own subject. American English writes paleontology; British often writes palaeontology. The word has been used since the 1800s.

古生物學