Geologic Timescale

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What is the Geologic Timescale?

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A system of chronological dating that relates geological strata to time, used to describe the timing and relationships of events in Earth's history.

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What are the three main eras of the Geologic Timescale?

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Paleozoic, Mesozoic, and Cenozoic.

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What significant event marks the end of the Mesozoic Era?

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The mass extinction event that led to the extinction of the dinosaurs.

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How old do scientists believe the Earth is?

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Approximately 4.6 billion years old.

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What is a fossil?

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The preserved remains or traces of ancient organisms, often found in sedimentary rock.

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What can studying fossil layers tell us?

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It can reveal which organisms lived before, after, or at the same time as others.

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What is the significance of the Cambrian Explosion?

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A period in the Paleozoic Era marked by a rapid diversification of life forms.

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What is the difference between an era and a period in the Geologic Timescale?

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An era is a larger division of time that encompasses multiple periods.

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What major changes define the boundaries of geologic time units?

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Major changes in life forms, such as mass extinctions or significant evolutionary developments.

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What is the Cenozoic Era known for?

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The era of recent life, characterized by the dominance of mammals and birds.