Types of Types of FossilsFossils

Pg. 44 of IAN

Objective: To learn about the different types of fossils.

Fossil:Fossil: The actual remains or evidenceThe actual remains or evidence of a living thing.of a living thing.

Detailed fossil of a mioplosus Detailed fossil of a mioplosus swallowing a small fish.swallowing a small fish.

Fossil ammoniteFossil ammonite

Detail of a fish fossil embedded in Detail of a fish fossil embedded in rock.rock.

Kinds of fossils:Kinds of fossils:

Each kind is identified according tothe process by which it was formed.

a. Petrificationa. Petrification:

A once living material is replacedby minerals, turning it to stone.

Petrified WoodPetrified Wood

Petrified LogPetrified Log

The logs literally turned to stone as minerals replacedThe logs literally turned to stone as minerals replaced wood cells when trees were buried during an ancient floodwood cells when trees were buried during an ancient flood..

b. Molds and Casts:b. Molds and Casts:

Mold:Mold: Type of fossil that forms as anoutline or cavity in a rock.

Cast:Cast: Type of fossil that forms whenmineral crystals fill a mold or sediments wash into a mold andharden into rock.

Fossil Shells (molds)Fossil Shells (molds)

Fossil trilobite (cast)Fossil trilobite (cast)

Fossil trilobite

c. imprints:c. imprints:Fossil formed when a thin objectleaves an impression in soft mud,which hardens.

Detail of a fossil fern embedded in rock.

d. Preservation of entire organismd. Preservation of entire organism

Freezing:Freezing: Freezing preserves things because it prevents them from decaying.

Preserved Woolly Mammoth

Amber:Amber: When the resin (sap) fromcertain evergreen trees hardens,it forms amber. Insects can be trapped.

Tar pits:Tar pits: Large pools of tar. Sticky tartrapped animals and eventually theysank.

e. Trace fossils:e. Trace fossils:

Non-body remains indicating the activities or behavior of an organism.Examples of trace fossils: tracks,trails, footprints, burrows, and fossilfeces.

Fossilized dinosaur footprintFossilized dinosaur footprint

burrows

tracks

TrailsTrails

• A trail is an impression made on a surface by the body of a limbless animal.

snail trail

CoprolitesCoprolites

•Coprolites are fossilized feces

Group Activity:

1. On a paper towel, flatten out a piece of clay.2. Press the animals shape into the clay.3. Remove the animal and put a thin layer of petroleum

jelly in the space where the animal was (press lightly as to not destroy the patterns)

4. Get a test tube of melted wax from your teacher. Pour the wax into the depression in the clay. STOP POURING WHEN THE DEPRESSION IN THE CLAY IS FULL.

5. Allow the wax to harden while you begin the discussion questions.

6. DRAW a PICTURE of your model “fossil”.