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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.
At the end of the Cretaceous, the impact of a large body with the Earth may have been the punctuation mark at the end of a progressive decline in biodiversity during the Maastrichtian age. The result was the extinction of three-quarters of Earth's plant and animal species.
The so-called "golden age" of neuropterans during the Middle Mesozoic, when gymnosperms dominated the flora, ended with the KTR and its reshaping of the terrestrial environment. [ 28 ] The KTR may have supercharged the contemporary Mesozoic Marine Revolution (MMR) by enhancing weathering and erosion, accelerating the flow of limiting nutrients ...
The Mesozoic Marine Revolution heavily affected the crinoids, making the majority of their forms extinct. Their sessile nature made them easy prey for durophagous predators since the Triassic. [9] Survivors (such as the comatulids) could swim or crawl, behaved nocturnally or had autotomy (the ability to shed limbs in defence). [12]
c. 251.9 Ma ± 0.024 Ma – Mesozoic era and Triassic Period begin. Mesozoic Marine Revolution begins. c. 245 Ma – First ichthyosaurs. c. 240 Ma – Cynodonts and rhynchosaurs diversify. c. 225 Ma – First dinosaurs and teleosti evolve. c. 220 Ma – First crocodilians and flies. c. 215 Ma – First turtles.
By the end of the period, Gondwana had neared or approached the pole and was largely glaciated. [ citation needed ] The Ordovician came to a close in a series of extinction events that, taken together, comprise the second-largest of the five major extinction events in Earth's history in terms of percentage of genera that became extinct.
The middle class has been steadily shrinking since 1971. According to the Pew Research Center, however, roughly 51% of Americans still fell into this category in 2023. While defining each class is...
Permian–Triassic boundary at Frazer Beach in New South Wales, with the End Permian extinction event located just above the coal layer [2]. Approximately 251.9 million years ago, the Permian–Triassic (P–T, P–Tr) extinction event (PTME; also known as the Late Permian extinction event, [3] the Latest Permian extinction event, [4] the End-Permian extinction event, [5] [6] and colloquially ...