Earth's History: Fossils

Front

What is radiometric dating?

Back

A method used by geologists to calculate the absolute age of rocks by knowing the half-life of an isotope.

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How are fossils created?

Back

Fossils are created when traces of organisms get turned into stone, dead organisms are quickly buried for millions of years, or animals get trapped.

Front

Where can the oldest layer of rock be found?

Back

The oldest layer can be found at the bottom layer of rock.

Front

What type of fossil includes nests, eggs, feces, and footprints?

Back

These are known as trace fossils.

Front

What are the three ways fossils are formed?

Back

Fossils can be formed through imprints, casts, and molds.

Front

What is a cast fossil?

Back

A cast fossil is a type of fossil that forms when a mold is filled with sediment or minerals, creating a replica of the original organism.

Front

What is a mold fossil?

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A mold fossil is an impression left in sediment when an organism decays, leaving a cavity in the shape of the organism.

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What are preserved remains?

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Preserved remains are fossils that include actual parts of the organism, such as bones, teeth, or shells, that have been preserved in substances like amber or ice.

Front

What is the principle of superposition?

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The principle of superposition states that in undisturbed layers of rock, the oldest layers are at the bottom and the youngest layers are at the top.

Front

What is the significance of fossils in understanding Earth's history?

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Fossils provide evidence of past life forms, their environments, and the changes that have occurred on Earth over time.