| A | B |
|---|
| sedimentary rock | what most fossils form in |
| fossil | the preserved remains of a plant,animal or other organism that lived on Earth long ago |
| how most fossils form | an organism dies and is quickly buried by sediment, the sediment hardens and traps and saves the remains. |
| trace fossil | evidence of animal's activity from a long ago |
| 3 trace fossil examples | footprints, wormholes and droppings |
| mold | an imprint made by the outside of dead plants or animals. |
| how molds are formed | when water slowly washes away the remains. |
| casts | formed when minerals & sediment fill in the mold |
| petrified | fossils that form when minerals slowly take place of original, once living thing |
| tree sap, glacier ice and tar pits | what whole animals and plants were trapped in and preserved as fossils |
| compare fossils to today's living things | how scientists know that living things have changed |
| animals & plants look like; how they moved; how the earth was long ago; & how living things have changed | fossils are important because they tell us these things: |
| using the order of rock layers that surround fossils and by studying the particles that decay in rocks | 2 ways scientists can find out the age of rocks and fossils |
| index fossils | fossils that are used to determine the age of newly found fossils |
