Notes Science Fossils What Are Fossils? SPI 0807.5.5 Fossils 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

8 Types of Fossils Notes Science Fossils A) Fossils In Rocks SPI 0807.5.5 Fossils 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

Notes Science Fossils A) Fossils In Rocks Found in sedimentary rock SPI 0807.5.5 Fossils 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

Notes Science Fossils B) Fossils In Amber SPI 0807.5.5 Fossils 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

Notes Science Fossils C) Petrified Fossils SPI 0807.5.5 Fossils Science 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

Saber Tooth Tiger Fossil (From La Brea Tar Pits, California) Notes SPI 0807.5.5 Fossils 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)

Notes Science Fossils E) Frozen Fossils SPI 0807.5.5 Fossils Science 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

Trace Fossil Dinosaur footprints Notes SPI 0807.5.5 Fossils 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 Dinosaur footprints Trace Fossil Imprint Of A Fish

Notes Science Fossils G) Mold/Cast Fossils SPI 0807.5.5 Fossils 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 Mold Fossil Cast Fossil

…we call these index fossils Notes SPI 0807.5.5 Fossils Science H) Index Fossils A way to relatively date rocks Some fossils are commonly found at certain strata levels across large geographic areas (A.K.A. relative dating) …we call these index fossils Example: Trilobite fossils Example: Ammonite fossils