Notes

1. SPI 0807.5.5 Relative Age of Fossils Notes Science • Create an 8 flap foldable. • Outside flap – label type of fossil • Inside flap - describe type of fossil. • Inside of foldable (center of paper) – draw each type of fossil and label the fossil.

2. SPI 0807.5.5 Relative Age of Fossils Notes Science • What Are Fossils? • Fossils are the preserved physical remains of deceased organisms that are at least 10,000 years old • NOTE: Most organisms DO NOT become fossils after death • NOTE: The formation of fossils is a RARE event • How Are Fossils Formed? • Watch this amusing video: Link: Video: How Fossils Are Made Primate Fossil: 47 million years old Whale Fossil: 25 million years old

3. SPI 0807.5.5 Relative Age of Fossils Notes Science 8 Types of Fossils A) Fossils In Rocks E) Frozen Fossils B) Fossils In Amber F) Trace Fossils C) Petrified Fossils G) Mold/Cast Fossils D) Fossils In Asphalt H) Index Fossils

4. SPI 0807.5.5 Relative Age of Fossils Notes Science A) Fossils In Rocks • Found in sedimentary rock • An organism died –was covered with mud, dirt, sand, ash, etc. • Later the mud, dirt, sand, or ash became sedimentary rock

5. SPI 0807.5.5 Relative Age of Fossils Notes Science B) Fossils In Amber • Tree sap fell on a small organism, enclosed it, & killed it • Over time the sap hardened into amber • The amber became covered with mud, dirt, sand, ash, etc. Example: Insects In Amber

6. C) Petrified Fossils • Organism died- then was covered with mud, dirt, sand, ash, etc. • The structure of the organism was replaced with minerals (Also known as petrifaction) Sometimes when wood is buried, groundwater will flow through the sediment and deposit minerals in the cells of the wood. The wood rots away & the minerals remain in the shape of the tree. Example: Petrified Wood Example: Petrified Wood

7. SPI 0807.5.5 Relative Age of Fossils Notes Science D) Fossils In Asphalt • Animals fell into tar pits, were trapped, and died • The asphalt hardened preserving skeletons, shells, teeth, etc. Saber Tooth Tiger Fossil (From La Brea Tar Pits, California)

8. E) Frozen Fossils • Animals died in a cold climate region and were frozen. • The cold temperatures preserved both soft and hard parts. • Many mammoths became frozen during the last ice age. Frozen Baby Mammoth (From Siberia, Russia) Approx. 42,000 yrs old Frozen Baby Mammoth (From Siberia, Russia) Approx: 40, 000 yrs old

9. SPI 0807.5.5 Relative Age of Fossils Notes Science F) Trace Fossils • Are impressions or “traces” left by plants and animals. • Can be simple tunnels or burrows in the mud. • Can be footprints or imprints in the mud etc. (Also called ichnofossils) Trace Fossil Imprint Of A Fish Trace Fossil Dinosaur footprints

10. SPI 0807.5.5 Relative Age of Fossils Notes Science G) Mold/Cast Fossils • In sediment, ground water may dissolve shells, leaving a shape called a mold. • Sometimes the shell dissolves and is replaced by minerals, leaving behind a mineral cast of the fossil. Cast Fossil Mold Fossil

11. H) Index Fossils • Some fossils are commonly found at certain strata levels. across large geographic areas. …we call these index fossils • Are used to estimate the rock’s age. (A.K.A. relative dating) Example: Trilobite fossils Example: Ammonite fossils