1. Fossils

2. Fossils- the preserved remains or evidence of living things

3. Types of Fossils
Original Remains- Unchanged remains of plants and animals
Examples
Hard parts: Bones, Shells
Animals trapped in ice: Wooly Mammoth
Animals trapped in tar or in amber

4. Woolly Mammoth in ice Saber-toothed Tiger Amber with an insect
Frog in Amber
Woolly Mammoth in ice

5. Fossilized dinosaur bones in sandstone (sedimentary rock)

7. The La Brea tar pit in Los Angeles, California is famous for its many fossils!
Tar is thick and sticky

8. Types of Fossils
Replaced Remains: Hard parts of plants or animals are replaced by minerals over time. The minerals are in the shape of the organism.
This occurs when water containing minerals seeps through the plant/animal material.
Petrified wood forms in this way

9. Petrified Wood Example:
Minerals have replaced all of the wood cells and turned this wood into rock!

11. Ice= Cast Types of Fossils Ice cube tray= Mold
Molds and Casts: Impressions and copies
Molds are created as mud or sediment becomes rock around dead organisms.
Casts are created as minerals get deposited into the molds and then harden. They make a copy of the fossil.
Ice=
Cast
Ice cube tray= Mold

12. Example: Cast of an Ammonite

13. Trace Fossils: Evidence of organisms
Types of Fossils
Trace Fossils: Evidence of organisms
Footprints, teeth marks, tunnels
Carbonaceous film: thin film of carbon resembling a silhouette of the organism

14. Index Fossils
**An Index fossil is a fossil used to determine the relative age rocks. **Relative age is the age compared to another rock It is not the true age of the rock It tells you if it is the same age, or if it is younger or older than another rock.

15. Requirements
To be an Index fossil, you must: 1. Be common (lots of them) 2. Be found in a lot of places worldwide (wide distribution) 3. Exist for a short period of time 4. Unique. Shouldn’t look like other fossils.

16. Trilobite: Index fossil of Paleozoic
Graptolite: Index fossil of the Silurian

17. Question:
Fossils are usually formed when the organism dies and gets buried in mud or sand. As a result, What type of rock are fossils usually found in?

18. Questions:
Why are fossils NOT usually found in igneous rock?

19. Questions:
What 4 settings (environments) could fossils be preserved?

20. Questions:
What are the 5 types of fossils?