1. IN: How do you think fossils form?
Put your DRW on the box
Looking at Fossils 12/16/14
6-4 pgs
IN: How do you think fossils form?

2. Fossil – any naturally preserved evidence of life.
What are fossils?
Fossil – any naturally preserved evidence of life.

3. Types of Fossils In Rocks Petrification In Amber Mummification
Frozen Fossils
In Tar
Trace Fossils
Molds and Casts

4. 1. In Rocks
Occasionally, body parts get buried quickly in sediment and are preserved while the sediment turns to rock.

5. What type of rock has fossils?
Sedimentary

6. Mineral Replacement
2. Petrification – a process in which an organism’s tissues are completely replaced by minerals.

7. 3. In Amber
Hardened tree sap is called amber.

8. 4. Mummification
When organisms die in dry places, such as deserts, they can sometimes dry out so fast that there isn’t enough time for even their soft parts to decay.

9. 5. Frozen Fossils
Animals freeze in glaciers and are preserved until the glacier thaws thousands of years later.

10. 6. In Tar
Organisms get trapped and sink in tar pits which preserve the organism.

11. La Brea Tar Pits, Los Angeles

12. 7. Trace Fossils – any naturally preserved evidence of an animal’s activity.
Tracks

13. Johnson Farm – St. George, Utah

14. Coprolites – preserved feces.

15. 8. Molds and Casts
A mold is a cavity in the ground or rock where a plant or animal was buried.
A cast is an object created when sediment fills a mold and becomes a rock.

16. Using Fossils to Interpret the Past
Fossils can reveal changes that have occurred in parts of the Earth.
Coral-reef fossils have been found in Iowa.
Fossils of marine organisms have been found on tops of mountains in Canada.

17. Using Fossils to Date Rocks
Index fossils – a fossil that is used to date the rock layers in which it is found.
Tropites lived between 230 million and 208 million years ago.

18. OUT: If you find rock layers containing fish fossils in a desert, what can you infer about that area of the desert?