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The K–Pg extinction event was severe, global, rapid, and selective, eliminating a vast number of species. Based on marine fossils, it is estimated that 75% or more of all species became extinct. [28] The event appears to have affected all continents at the same time.
A 2016 estimate put the number of dinosaur species living in the Mesozoic at 1,543–2,468, [21] [22] compared to the number of modern-day birds (avian dinosaurs) at 10,806 species. [23] Extinct dinosaurs, as well as modern birds, include genera that are herbivorous and others carnivorous, including seed-eaters, fish-eaters, insectivores, and ...
End Triassic: 200 million years ago, 80% of species lost, including all conodonts; End Cretaceous: 66 million years ago, 76% of species lost, including all ammonites, mosasaurs, plesiosaurs, pterosaurs, and nonavian dinosaurs; Smaller extinction events have occurred in the periods between, with some dividing geologic time periods and epochs.
John M. Cys argued that dinosaurs went extinct because they were unable to hibernate during the winter, leaving them doomed by Earth's changing climate. [23] 1968. Daniel I. Axelrod and Harry Paul Bailey proposed that the dinosaurs were driven extinct when Earth's climate began exhibiting more marked seasons rather than stable conditions year ...
They first appeared in the fossil record around 66 million years ago, soon after the Cretaceous–Paleogene extinction event that eliminated about three-quarters of plant and animal species on Earth, including most dinosaurs. [25] [26] One of the last Plesiadapiformes is Carpolestes simpsoni, having grasping digits but not forward-facing eyes.
An international team found dinosaurs had been evolving and expanding, but showed a sudden downturn around 76 million years ago. Dinosaurs were in decline up to 10 million years before asteroid ...
About 17% of all families, 50% of all genera [6] and 75% of all species became extinct. [2] In the seas all the ammonites, plesiosaurs and mosasaurs disappeared and the percentage of sessile animals was reduced to about 33%. All known non-avian dinosaurs became extinct during that time. [20]
Date Probable causes [2] Quaternary: Holocene extinction: c. 10,000 BC – Ongoing: Humans [3] Quaternary extinction event: 640,000, 74,000, and 13,000 years ago: Unknown; may include climate changes, massive volcanic eruptions and Humans (largely by human overhunting) [4] [5] [6] Neogene: Pliocene–Pleistocene boundary extinction: 2 Ma