Mesozoic Mesozoic Mental function Category="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.) Mesozoic gets its name from the Greek meso (middle) and zoo (animals) and is often called the "Age of Medieval Life."

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 ago (Ma) to roughly 65 Ma. 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.

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.

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.

Phanerozoic eon
Paleozoic eraMesozoic eraCenozoic era

Mesozoic era
TriassicJurassicCretaceous

See also

References and further reading