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23 Cards in this Set

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Carbonized fossil

Forms when organisms or parts are pressed between layers of soft mud or clay that hardens squeezing almost all the decaying organism away leaving the carbon imprint in the rock.

Cast fossil

Forms when a mold is filled with sand or mud that hardens into the shape of the organism


The preserved remains or traces of an organism that lived in the past.

Fossil record

Gives important information about past life and environments on earth. Extinction of life forms as well as how and when new life forms appeared is part of this.

Mold fossil

Forms when sediments bury an organism, change into rock, organism decays leaving a cavity in the shape of the organism.

Petrified fossil

Forms when minerals soak into buried remains, replacing the remains, and changing them into rock.

Preserved fossil

Forms when entire organisms or parts of organisms are prevented from decaying by being trapped in rock, ice, tar, or amber.

Trace fossil

Forms when the mud or sand hardens into stone where a footprint, trail, or burrow of and organism was left behind.


First period


Smallest unit of geologic time.


Longest unit of geologic time that is divided into periods

Middle era


Oldest era



Can be further divided into epochs


Name given to the earliest span of time in earths history

Present day epoch

Holocene epoch

Present day era

Cenozoic era

Present day period

Quatemary period

Youngest era


Asteroid or comet

Caused many groups of animals to disappear suddenly at the end of the Mesozoic era


An event causing great and often sudden damage or suffering

Cenozoic era

Major ice ages caused climate to be much cooler, mountain ranges formed causing climate differences due to elevation


No members of that species are still alive.