Fossil Study Guide Answers
Quiz Thursday 4/9/15
1. A fossil is a preserved clue to life on earth long ago OR the hardened remains or traces of an animal or
plant from long ago.
2. A trace fossil is a fossil of an animal’s footprints, droppings, nests, eggs, or burrows that shows activity
OR fossils that show changes that long-dead animals made in their surroundings.
3. A mold is a fossil made when an animal or plant rots (decays) away leaving its shape in the rock OR a
fossil imprint made by the outside of a dead plant or animal.
4. A cast is a fossil made when minerals take the place of hard plant or animal parts OR a fossil formed
when sediments or minerals fill a mold; it takes on the same outside shape as the living thing that
shaped the mold.
5. A paleontologist is a scientist that studies fossils.
6. How do most fossils form? When dead plants or animals are buried quickly by sediments.
7. Name 3 ways that a whole plant or animal could have been preserved as a fossil? Stuck in tree sap that
turned into amber, stuck in a tar pit, frozen in a glacier (ice).
8. How does petrified wood form? Water containing minerals soaks into fallen trees. The wood slowly
rotted away and minerals took its place. It turns into rock/stone.
9. Why are fossils important? The tell us what life was like in the past, give evidence to long-dead animals,
tells us when animals went extent, helps us see how things have changed over time…. etc
10. What is one way a scientist can find out the age of a rock? The test the old particles in the layers to the
new particles and compare them OR they look at the different layers or rock- oldest on bottom and
youngest on top.
11. What is the fossil record? Layers of rock containing fossils that help tell the story of life on earth OR all
the fossils that tell us about the history of the earth.
12. What are some examples of trace fossils? Footprints, droppings, burrows, nest with eggs
13. How common are fossils? Why? Not very common. Dead plants and animals were more likely to be
eaten by scavengers, predators, or decomposers before they had a chance to fossilize. Even after they
have become fossils the rock can be eroded, crushes, melted, broken destroying the fossil.
14. If scientist found a fossil in the middle layer of the ground that was 3 million years old, would they think
Earth was more or less than 3 million years old? Explain your answer. More because it was found in the
middle layer- the layers under or below that level are older than the middle level meaning things were
living/happening before the life of the middle layer fossil.