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The Mesozoic is the middle of the three eras since complex life evolved: the Paleozoic, the Mesozoic, and the Cenozoic. The era began in the wake of the Permian–Triassic extinction event , the largest mass extinction in Earth's history, and ended with the Cretaceous–Paleogene extinction event , another mass extinction whose victims included ...
The Cretaceous (IPA: / k r ɪ ˈ t eɪ ʃ ə s / krih-TAY-shəss) [2] is a geological period that lasted from about 143.1 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest.
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.
It marked the end of the Cretaceous period, and with it the Mesozoic era, while heralding the beginning of the current era, the Cenozoic. In the geologic record , the K–Pg event is marked by a thin layer of sediment called the K–Pg boundary, Fatkito boundary or K–T boundary , which can be found throughout the world in marine and ...
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.
The middle class as we know it emerged in the post-World War II era. This cohort, sandwiched between the wealthy and the working class, makes up the biggest percentage of Americans, but that could ...
Many people are content with living a middle-class lifestyle. But what does middle class even mean, anyway? Pew Research Center defines middle class as having an income that's between two-thirds ...
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 ...