T-RexDo you recognize this animal from its skeleton? If you guessed it’s Tyrannosaurus rex, you’re right. Like other dinosaurs, T. rex went extinct about 65 million years ago. How do we know what this extinct animal looked like? The answer is right in front of you: from the fossils it left behind. This T. rex isn’t a true fossil. It’s just a copy on display in a museum. But many fossils of T. rex have been found. Fossils not only show us what extinct animals looked like. They also provide evidence about past environments and geological processes. In this chapter, you’ll find out how scientists use clues from fossils to understand Earth’s history.

Image copyright Geoff Hardy, 2014. Used under license from