Date post: | 01-Nov-2014 |
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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!!