1. May 19, 2010 What was the purpose of the timeline activity?
What is the name of the era we are living in today?

3. Evidence Supporting Evolution
FOSSILS
any preserved evidence of an organism
Estimated that 99% of species that have ever lived are extinct!
Mostly formed in sedimentary rock
Fossilization
How a fossil is made

4. Activity
Cut out the “fossils” and put them together to determine what organism it was!

5. Diprotodon Giant wombat or Rhinoceros wombat
Largest marsupial ever to live
1.6 mil – 45,000 ya

6. How do we date fossils? Law of Superposition
Newer fossils are found relatively close to the surface while older fossils are found deeper underground.
(relative dating)

7. How do scientists date CARBON?
How do we date fossils?
Radiometric Dating
Uses the half life decay of radioactive material to determine age.
(actual dates)
How do scientists date CARBON?

8. Trace Fossil Indirect evidence left behind Footprints Burrows
Animal waste

9. Dinosaur Ridge
Morrison, Colorado

12. Molds and Casts
Organisms buried in sediment may decay or dissolve away leaving a mold.
If the space fills with sediment, an external cast can be made.
Molds and casts are three dimensional and preserve the surface contours of the organism.

13. Replacement Original organism material is replaced by minerals
Can leave replicas of hard tissue (shells, bones, etc) or soft tissue (muscle, fat, etc)

14. Petrified
Empty spaces are filled with minerals

15. Amber
Tree sap hardens into amber
Preserves specimen

16. Original Material
Mummified/frozen organisms

17. Who studies fossils?
Paleontologists
Reconstruction of Ichthyosaurus.

18. rock formed by the growth of blue-green algae or cyanobacteria
stromatilite
Trace fossil
rock formed by the growth of blue-green algae or cyanobacteria

19. ammonites
Replacement/Mold and Cast
415 million years ago

20. Today’s organisms believed to be derived from ammonites