Geologic Time

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What is Geologic Time?

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Geologic Time is the timeline of Earth's history, divided into different intervals based on significant geological and biological events.

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What are the main divisions of Geologic Time?

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The main divisions are Eons, Eras, Periods, and Epochs.

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What does the Law of Superposition state?

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In an undisturbed sequence of sedimentary rocks, the oldest layers are at the bottom and the youngest layers are at the top.

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What is a fossil?

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A fossil is the preserved remains or traces of ancient organisms.

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Why is the fossil record considered incomplete?

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The fossil record is incomplete because many organisms never became fossils, fossils can be eroded away, and scavengers and decomposers can destroy them.

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What era do mammals dominate?

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Mammals are dominant in the Cenozoic Era.

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When did humans first appear in the geologic timeline?

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Humans appeared relatively recently in the geologic timeline.

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What is the significance of the Cenozoic Era?

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The Cenozoic Era is significant for the development of mammals and birds, and it is the current geological era.

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What major event marks the end of the Mesozoic Era?

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The mass extinction event that wiped out the dinosaurs marks the end of the Mesozoic Era.

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What is the difference between the Paleozoic and Mesozoic Eras?

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The Paleozoic Era is known for the development of early life forms, while the Mesozoic Era is known as the age of reptiles, including dinosaurs.