1. Fossils

2. What is a fossil?
A fossil is an impression, cast,
original material or track of any animal or plant that is preserved in rock after the original organic material is transformed or removed.

3. What are Fossils?
Most fossils form when a living organism dies and is buried by sediment.
The sediment slowly hardens into rock and preserves the shapes of the organism.

4. A fossil may be: an original skeleton or shell; a mold or cast;
material that has replaced the once living thing;
traces such as footprints or worm tubes

5. What conditions promote fossilization?
Hard body parts such as skeletal bones or exoskeletons

6. What conditions promote fossilization?
Rapid burial and/or lack of oxygen

7. What are the fossil types?
Body fossils – actual parts of an organism, unaltered or altered
bones, shells, leaf imprints
Trace fossils – evidence of life that is not a body fossil
tracks, burrows, casts

8. Body fossils

9. Trace Fossils

10. What are the modes of fossil preservation for body fossils?
Unaltered
Original Material - original,
unaltered material from the living organism unaltered bone or shell
Encrustations or entombments –
material is trapped inside coating such as amber

11. What are the modes of fossil preservation for body fossils?
Unaltered
Mummification - quickly dried material
Refrigeration –
material is trapped inside ice and tissue is preserved

12. What are the modes of fossil preservation?
Altered
Permineralization – pores in tissue are filled by minerals
Replacement – replacement of tissue with minerals

13. What are the modes of fossil preservation for body fossils?
Altered
Carbonization – tissue material is decomposed or reduced to a film of carbon

14. More on trace fossils
Mold – reproduction of the inside or outside surface of a living thing. It is a hollow area in sediment in the shape of the organism.
Cast – duplicate of the original organism; it is a solid
Copy of the shape of the living being.

15. More on trace fossils Burrows or borings Petrified fossils.
Spaces dug out by living things and preserved as is or filled in by minerals.

16. More on trace fossils
Gastroliths – smooth stones from abdominal cavity of dinosaurs
Coprolites – fossilized excrement; usually preserved by replacement

17. More on trace fossils
Tracks – impressions of passage of living things

18. Carbon Films
Extremely thin coating of carbon on rock. When sediment buries an organism, some gases escape from the sediment , leaving carbon behind.

19. Carbon Films
Fossils called carbon films can preserve delicate details of leaves and animal parts.

20. Trace Fossils Provide evidence of the activities of ancient organisms:
Foot print.
Trails
Burrows

21. Preserved Remains Some processes can preserve entire organisms.
Sticky tar.
Tree resin.
Freezing.

22. Paleontologist Scientists who study fossils.
The fossil record provides evidence about the history of life and past environments on Earth.
Fossils provide evidence about the past.

23. Evolution It is the change of living things over time.
Fossil record shows that millions of types of organisms have evolved.
Others become extinct.
Fossils are used to reconstruct extinct organisms and determine how they may be related with living being in our present time.