Fossils - Academic Computer Center

Fossils What is a fossil? A fossil is an impression, cast, original material or track of any animal or plant that is preserved in rock after the original organic material is

transformed or removed. A fossil may be: an original skeleton or shell; a mold or cast; material that has replaced the once

living thing; traces such as footprints or worm tubes What conditions promote fossilization? Hard body parts

such as skeletal bones or exoskeletons What conditions promote fossilization? Rapid burial and/or lack of oxygen

What are the fossil types? Body fossils actual parts of an organism, unaltered or altered bones, shells, leaf imprints Trace fossils evidence of life that is not a body fossil tracks, burrows, casts

Body fossils Trace Fossils What are the modes of fossil preservation for body fossils? Unaltered

Original Material - original, unaltered material from the living organism unaltered bone or shell Encrustations or entombments material is trapped inside coating such as amber

What are the modes of fossil preservation for body fossils? Unaltered Mummification quickly dried material Refrigeration material is trapped inside ice and tissue is

preserved What are the modes of fossil preservation? Altered Permineralization pores in tissue are filled by minerals

Replacement replacement of tissue with minerals What are the modes of fossil preservation for body fossils? Altered

Carbonization tissue material is decomposed or reduced to a film of carbon More on trace fossils Mold reproduction

of the inside or outside surface of a living thing Cast duplicate of the original organism; usually formed by replacement of

inside of living thing More on trace fossils Burrows or borings Spaces dug out by living things and preserved as is or

filled in More on trace fossils Gastroliths smooth stones from abdominal cavity of dinosaurs Coprolites

fossilized excrement; usually preserved by replacement More on trace fossils Tracks impressions of

passage of living things