A trip through geologic time: Fossils. Uniformitarianism The present is the key to the past. The...

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A trip through geologic ti Fossils

Transcript of A trip through geologic time: Fossils. Uniformitarianism The present is the key to the past. The...

Page 1: A trip through geologic time: Fossils. Uniformitarianism The present is the key to the past. The same geologic processes that operate today operated in.

A trip through geologic time:Fossils

Page 2: A trip through geologic time: Fossils. Uniformitarianism The present is the key to the past. The same geologic processes that operate today operated in.

Uniformitarianism

• The present is the key to the past.• The same geologic processes that operate

today operated in the past

Fossil fish- not a goldfish

Page 3: A trip through geologic time: Fossils. Uniformitarianism The present is the key to the past. The same geologic processes that operate today operated in.

Fossils: evidence of past life

Fossil Formation:1. organism dies2. organism buried in sediment 3. sediments slowly harden into

rock preserving the parts of the organism

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Most important conditions for fossil formation

• Rapid burial• Hard parts

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Types of Fossils

Mold and Cast1.organism dies, gets buried, decomposes – leaves behind a hole the shape of the original organism ( the mold)2.Water washes in sediments which fill in the mold and solidify to form a rock with the same external structure as the organism had (the cast)

Trilobite fossil

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• Petrified: (mineralized) fossils- organism dies, every molecule of the organism is replaced by a molecule of a mineral

• This shows the internal structure as well as the external structure.

Petrified Wood

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Actual Fossils

The actual organism frozen in ice or amber (tree sap)

Termites in amber

Frog in amber

Baby mammoth frozen in ice

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Trace Fossils:evidence that an organism has been there

coprolyteDinosaur footprint

gastroliths

Dinosaur tracks

Worm casings

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Carbon films: an extremely thin coating of carbon on rock

Leaf fossil

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Index Fossil: fossils of widely distributed organisms that lived during

only one short period.

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http://cartage.org.lb/en/themes/sciences/Paleontology/FossilsAndFossilisation/AmberFossils/AmberFossils/AmberFossils.htm

http://news.bbc.co.uk/2/hi/6284214.stm

http://www.envs.emory.edu/faculty/MARTIN/ichnology/tf-eggs.htm

http://en.wikipedia.org/wiki/Gastrolith

http://www.clas.ufl.edu/users/pciesiel/gly3603c/fossils.html

http://pubs.usgs.gov/gip/geotime/fossils.html

Picture bibliography