Fossils have been discovered that represent most living groups, even those that are now extinct, some dating back 3.5 billion years.
Fossils are records of ancient life on earth.
They contain evidence of how life has changed and evolved throughout the earth's history and provide a tangible link to the past. Fossils of extinct organisms are compared with living organisms to draw conclusions about their nature, behavior, and habits. When combined with geology, fossils provide evidence of where ancient life lived. In order to locate a place where fossils might be found, it's helpful to understand what kinds of fossils there are and how they were formed, so you can pinpoint the right places where the conditions existed to make fossils. There are many kinds of fossils but there are only a few ways they are formed.