Explain what a fossil is and how scientists use fossil evidence to learn about organisms and environments from long ago.
A fossil is the preserved remains or trace of a living thing from long ago, sometimes millions of years old, such as a bone turned to stone, a footprint hardened in mud and rock, or even the imprint of a leaf. Fossils are not only bones; footprints, imprints, and other traces count too.
Scientists study fossils as evidence to figure out what kinds of plants and animals lived in a place long ago, and what that environment might have been like at the time, even if today's environment looks completely different.
Mastery looks like: They explain at least one specific thing fossil evidence reveals about an ancient organism or its environment, using a real example.
Common stumbles: Assuming fossils are only bones, or assuming an area's environment today must match what it was like long ago.