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It began 541 million years ago with the Cambrian explosion, an extraordinary diversification of marine animals, and ended about 252 million years ago with the end-Permian extinction, the greatest extinction event in Earth history.
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The Cambrian period, part of the Paleozoic era, produced the most intense burst of evolution ever known.
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Ordovician Period, in geologic time, the second period of the Paleozoic Era. It began 485.4 million years ago, following the Cambrian Period, and ended 443.8 million years ago, when the Silurian Period began
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The Silurian Period occurred from 443 million to 416 million years ago. It was the third period in the Paleozoic Era. It followed the Ordovician Period and preceded the Devonian Period. During this time, continental landmasses were low and sea levels were rising.
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Devonian Period, in geologic time, an interval of the Paleozoic Era that follows the Silurian Period and precedes the Carboniferous Period, spanning between about 419.2 million and 358.9 million years ago. Late in the period the first four-legged amphibians appeared, indicating the colonization of land by vertebrates.
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The Carboniferous period, part of the late Paleozoic era, takes its name from large underground coal deposits that date to it. Formed from prehistoric vegetation, the majority of these deposits are found in parts of Europe, North America, and Asia that were lush, tropically located regions during the Carboniferous.
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The Permian period, which ended in the largest mass extinction the Earth has ever known, began about 299 million years ago. The emerging supercontinent of Pangaea presented severe extremes of climate and environment due to its vast size. The south was cold and arid, with much of the region frozen under ice caps.
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During the Mesozoic era, life diversified rapidly and giant reptiles, dinosaurs and other monstrous beasts roamed the Earth.
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he Triassic Period is approximately 51 million years of Earth history, from 201–252 million years ago. Deposition across and around Triassic Pangaea took place mostly in foreland, fore-arc and extensional basins, and the Triassic was a time of relatively low levels of volcanism.
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Jurassic Period, second of three periods of the Mesozoic Era. Extending from 201.3 million to 145 million years ago, it immediately followed the Triassic Period (251.9 million to 201.3 million years ago) and was succeeded by the Cretaceous Period
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Cretaceous Period, in geologic time, the last of the three periods of the Mesozoic Era. The Cretaceous is the longest period of the Phanerozoic Eon. Spanning 79 million years, it represents more time than has elapsed since the extinction of the dinosaurs, which occurred at the end of the period.
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Cenozoic Era, third of the major eras of Earth's history, beginning about 66 million years ago and extending to the present. It was the interval of time during which the continents assumed their modern configuration and geographic positions and during which Earth's flora and fauna evolved toward those of the present.
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This period began 65 million years ago and ended roughly 1.8 million years ago and bore witness to some major geological, biological and climatological events. This included the current configuration of the continents, the cooling of global temperatures, and the rise of mammals as the planet's dominant vertebrates.
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The Quaternary Period is the second period of the Cenozoic Era. You and I are living in this period, which began only 1.8 million years ago. This is less than 0.1% of all of geologic time! A thin layer of sediments deposited during the Quaternary covers much of the Earth's land surface.
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