In geological ages, which period was the first of the Mesozoic Era?
Mesozoic Following the Paleozoic, the Mesozoic extended roughly 186 million years, from when the Cenozoic Era began. This time frame is separated into three geologic periods. From oldest to youngest: The lower boundary of the Mesozoic is set by the Permian–Triassic extinction event, during which approximately 90% to 96% of marine species and 70% of terrestrial vertebrates became extinct. It is also known as the "Great Dying" because it is considered the largest mass extinction in the Earth's history. The upper boundary of the Mesozoic is set at the Cretaceous–Paleogene extinction event (or K–Pg extinction event), which may have been caused
Mesozoic Mesozoic The Mesozoic Era ( or ) is an interval of geological time from about . It is also called the Age of Reptiles, a phrase introduced by the 19th century paleontologist Gideon Mantell who viewed it as dominated by diapsids such as "Iguanodon", "Megalosaurus", "Plesiosaurus" and "Pterodactylus". To paleobotanists, this Era is also called the Age of Conifers. "Mesozoic" means "middle life", deriving from the Greek prefix "meso-"/"μεσο-" for "between" and "zōon"/"ζῷον" meaning "animal" or "living being". The name "Mesozoic" was proposed in 1840 by the British geologist John Phillips (1800–1874). It is one of three geologic eras of