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The Mesozoic Era [3] is the era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Periods.It is characterized by the dominance of gymnosperms such as cycads, ginkgoaceae and araucarian conifers, and of archosaurian reptiles such as the dinosaurs; a hot greenhouse climate; and the tectonic break-up of Pangaea.
The Triassic is the first and shortest period of the Mesozoic Era and the seventh period of the Phanerozoic Eon. Both the start and end of the period are marked by major extinction events. [10] The Triassic Period is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic.
The Precambrian includes approximately 90% of geologic time. It extends from 4.6 billion years ago to the beginning of the Cambrian Period (about 539 Ma).It includes the first three of the four eons of Earth's prehistory (the Hadean, Archean and Proterozoic) and precedes the Phanerozoic eon.
Dinosaurs trod the planet from about 231 million years ago to 66 million years ago during the Mesozoic Era. Their bird descendants remain with us today. ... is about 4.5 billion years old ...
Of all the phases Earth has been through, the Mesozoic Era stands out among the rest—even from off-world. Skip to main content. Sign in. Mail. 24/7 Help. For premium support please call: 800-290 ...
The succeeding eon is the Phanerozoic, divided into three eras: the Palaeozoic, an era of arthropods, fishes, and the first life on land; the Mesozoic, which spanned the rise, reign, and climactic extinction of the non-avian dinosaurs; and the Cenozoic, which saw the rise of mammals. Recognizable humans emerged at most 2 million years ago, a ...
By the end of the Mesozoic, the Appalachian Mountains had been eroded to an almost-flat plain. [10] It was not until the region was uplifted during the Cenozoic era that the distinctive topography of the present formed. [11] Uplift rejuvenated the streams, which rapidly responded by cutting downward into the ancient bedrock. Some streams flowed ...
Following the Permian–Triassic extinction event, the most devastating of all mass-extinctions, life recovered slowly.In the Middle Triassic, many groups of organisms reached higher diversity again, such as the marine reptiles (e.g. ichthyosaurs, sauropterygians, thallatosaurs), ray-finned fish and many invertebrate groups like molluscs (ammonoids, bivalves, gastropods).