fossils

Fossils• Preserved

remains of living things

• Provide scientists (paleontologists) with evidence of how life on Earth has changed over time

Fossil Formation

http://www.youtube.com/watch?v=G4jM2t3NHPA&feature=related

Fossil FormationFossil FormationA. Organism dies and is quickly

buried by sediment (this protects the organism)

B. Minerals replace all or part of organisms original structure

A. More delicate parts often decay before this can happen

C. Sediment hardens and turns into rock

Mold and Cast Fossils

• Most common• Mold – hollow area in

shape of organism

• Cast – copy of the

organism

• Mold & Cast are opposites

Mold and Cast Fossils

Provides evidence of:•Organism’s physical characteristics (size, shape, etc)

– Limited to the structures that are able to be preserved

•May also provide clues to environment in which organism lived

Petrified Fossils• Minerals replace

all or part of an organism– Occurs when

water rich in minerals is absorbed into organisms cells

– Petrified means turned into stone

Petrified Fossils• Provides

evidence of:–Size of

organism–Age of

organism (esp. if a tree)–Past

environments

Carbon Film• Extremely thin

layer of carbon on a rock in the shape of the organism

• Preserves delicate parts of plant leaves and insects

Preserved Remains

• Organisms preserved with little or no change to original structure

• Occurs when organism is trapped in a substance that assists in the preservation– Tar, amber, ice

Preserved

Remains• Provides

evidence of–Physical

structures that are often lost through other fossilization processes

Trace Fossils• Provides evidence

of the activities of ancient organisms

• Examples include footprints, burrows and trails

Reflection Page 40

• Identify which of the 6 fossils types is the most important for scientists as they unravel the history of the earth– Justify your

answer!!