Mesozoic

The Mesozoic is one of three geologic eras of the Phanerozoic eon. The division of time into eras dates back to Giovanni Arduino in the 18th century, although his original name for the era now called the Mesozoic was "Secondary". (See Tertiary)

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The Mesozoic includes three Geologic Periods: from oldest to youngest, they are the Triassic, the Jurassic and the Cretaceous periods. It extended from roughly 251 million years before present to roughly 65 million years. The Mesozoic followed the Paleozoic Era and preceded the Cenozoic Era. The lower (oldest) boundary is set by the Permian extinction. The upper (youngest) boundary is set at the Cretaceous extinction.

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The Mesozoic spans the period when terrestrial life was dominated by large sophisticated reptiles, the basis for its popular designation as "the Age of the Dinosaurs". The era also witnessed the development of early birds and mammals, and of the first flowering plants (angiosperms). At the end of the Mesozoic, all the major body plans of modern life were in place although in some cases—notably the mammals—the forms that existed at the end of the Cretaceous were relatively primitive.

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Geologically, the Mesozoic starts with almost all the Earth's land surface collected into a supercontinent called Pangaea. During the Mesozoic Era, however, Pangaea split into a northern continent Laurasia and a southern continent Gondwana. Laurasia subsequently divided into North America and Eurasia, whilst Gondwana broke up progressively into the four present continents of South America, Africa, Australia and Antarctica.

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Phanerozoic: The Phanerozoic (occasionally Phaenerozoic) Eon is the period of geologic time during which abundant animal life has existed. It covers roughly 545 million years ago back to the time when diverse hard-shelled animals first appeared. The Phanerozoic eon is still ongoing. The time previous to the star...

Eon: There are several uses of the word eon or Eon....

Giovanni Arduino: Giovanni Arduino (Caprino Veronese, October 16, 1714 – Venice, March 21, 1795) was an Italian geologist who is known as the "Father of Italian Geology."...