Fossil Evidence of Evolution

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Fossil Noun

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[fos-uhl]

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Fossil

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The preserved remains or evidence of a once-living organism from a past geological age, embedded in rock.

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Example: The image shows how a dinosaur becomes a fossil as it gets buried by sediment over time.

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Mineralization Noun

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[min-er-uh-luh-zay-shuhn]

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Mineralization

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A fossilization process where minerals in water fill spaces in an organism's tissues, preserving its internal structures.

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Example: Fossilized dinosaur bones show how minerals replace organic material, preserving the structure.

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Carbonization Noun

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[kahr-buh-nuh-zay-shuhn]

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Carbonization

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A fossilization process where pressure removes an organism's liquids and gases, leaving a thin carbon film outline.

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Example: A leaf fossil shows carbonization, where pressure leaves a carbon film outline.

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Mold Noun

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[mohld]

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Mold

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A type of fossil that is an impression or cavity of an organism left in sediment that has hardened.

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Example: This image shows a mold fossil, which is an impression left by an organism in rock.

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Cast Noun

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[kast]

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Cast

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A fossil formed when a mold is filled with sediment that hardens, creating a copy of the organism's shape.

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Example: The image shows molds and casts, demonstrating how a cast fossil forms when a mold is filled with sediment.

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Trace Fossil Noun

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[trays fos-uhl]

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Trace Fossil

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The preserved evidence of an organism's activity, such as footprints or burrows, rather than the organism itself.

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Example: A dinosaur footprint fossil shows evidence of its activity, not the dinosaur itself.

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Original Material Noun

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[uh-rij-uh-nl muh-teer-ee-uhl]

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Original Material

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A type of fossilization where the actual soft or hard tissues of an organism are preserved without significant change.

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Example: Insects preserved in resin show original material fossilization, keeping the organism intact.

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Fossil Record Noun

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[fos-uhl rek-erd]

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Fossil Record

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The complete collection of all fossils ever discovered on Earth, documenting the history of life over geologic time.

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Example: Fossils form over time as layers of sediment cover remains, creating a fossil record.

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Relative-Age Dating Noun

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[rel-uh-tiv ayj day-ting]

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Relative-Age Dating

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A method used to determine the relative order of past events by comparing the positions of rock layers.

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Example: Rock layers show the order of events, helping to determine which layers are older or younger.

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Absolute-Age Dating Noun

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[ab-suh-loot ayj day-ting]

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Absolute-Age Dating

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A precise method of determining a rock's or fossil's age in years, often using radioactive decay measurements.

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Example: The graph shows how a substance's amount decreases over time, helping determine the age of rocks or fossils using radioactive decay.