A fossil is the name given to the re- mains or traces of a plant or animal preserved in geologic strata since prehistoric times—or in some cases, re- mains preserved encased in amber. Fossils collected from all over the world are one of our most important sources of information about the organisms that have ex-isted on Earth since the very earliest times, even hundreds of millions of years ago. Research into fossils enables us to learn about extinct plants and animals, as well as earlier forms of species still in existence today. Thanks to this information, we learn which life forms existed at what epochs in time, what these life forms' features were, and whether they resembled present-day species.