Vocab List # 10

Front

Remains or traces of prehistoric organisms that indicate their existence and lifestyle.

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Fossils

Front

Forms when sediments bury an organism, changing into rock; the organism decays, leaving a cavity in its shape.

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Mold fossil

Front

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

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Cast fossil

Front

Forms when minerals replace buried remains, turning them into rock.

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Petrified fossil (permineralized fossil)

Front

Forms when organisms or parts are trapped in rock, ice, tar, or amber.

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Preserved fossil

Front

Forms when organisms or parts (leaves, stems, flowers, fish) are pressed between soft mud or clay, hardening and leaving a carbon imprint in rock.

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Carbonized fossil

Front

Forms when mud or sand hardens around an organism's footprint, trail, or burrow.

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Trace fossil

Front

Division of Earth's history into time units based on life-forms present during specific periods.

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Geologic Time Scale

Front

Longest part of Earth’s history (4 billion to 544 million years ago)

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Precambrian Era

Front

Era of ancient life (544-245 million years ago) with hard parts and mass extinctions.

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Paleozoic Era