Geological Time Scale and Fossils

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What is the Principle of Superposition?

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In a sequence of undisturbed rocks, the oldest rocks are on the bottom and the rocks become progressively younger toward the top.

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What is an index fossil?

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An index fossil is a fossil that is used to define and identify a particular time period in the geological time scale.

Front

During which era did modern humans evolve?

Back

Cenozoic Era.

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What is a carbon film fossil?

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A fossil that consists of a thin layer of carbon atoms and molecules, preserving the outline of the organism.

Front

What does the Geological Time Scale represent?

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A chronological chart that shows the events and past lives of organisms in Earth's history.

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What is uniformitarianism?

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The principle that the same geological processes that operate today also operated in the past.

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What are original remains?

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Fossils that consist of the actual remains of the organism, such as bones or shells.

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What is a trace fossil?

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A fossil that provides evidence of the activity of an organism, such as footprints or burrows.

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What is the significance of the Cambrian Explosion?

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A period in the geological time scale marked by a rapid diversification of life forms.

Front

What are the three main eras of the Phanerozoic Eon?

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Paleozoic, Mesozoic, and Cenozoic.