Fossils Fossils Fossils the preserved remains or evidence

Fossils

Fossils • Fossils- the preserved remains or evidence of living things

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

Amber with an insect Frog in Amber Sabertoothed Tiger Woolly Mammoth in ice

Fossilized dinosaur bones in sandstone (sedimentary rock)

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

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

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

Types of Fossils • 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 cube tray= Mold Ice= Cast

Example: Cast of an Ammonite

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

Trilobite: Index fossil of Paleozoic • Graptolite: Index fossil of the Silurian

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?

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

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

Questions: • What are the 5 types of fossils?