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End Ordovician: 440 million years ago, 86% of all species lost, including graptolites. Late Devonian: 375 million years ago, 75% of species lost, including most trilobites. End Permian, The Great Dying: 251 million years ago, 96% of species lost, including tabulate corals, and most trees and synapsids.
The Cretaceous–Paleogene (K–Pg) extinction event, [a] also known as the Cretaceous–Tertiary (K–T) extinction, [b] was the mass extinction of three-quarters of the plant and animal species on Earth [2][3] approximately 66 million years ago. The event caused the extinction of all non-avian dinosaurs.
Free-air gravity anomaly over the Chicxulub structure (coastline and state boundaries shown as black lines) The Chicxulub crater (IPA: [t͡ʃikʃuˈluɓ] ⓘ cheek-shoo-LOOB) is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is offshore, but the crater is named after the onshore community of Chicxulub Pueblo ...
Mary Higby Schweitzer is an American paleontologist at North Carolina State University, who led the groups that discovered the remains of blood cells in dinosaur fossils and later discovered soft tissue remains in the Tyrannosaurus rex specimen MOR 1125, [1] [2] as well as evidence that the specimen was a pregnant female when she died.
The Alvarez hypothesis posits that the mass extinction of the non-avian dinosaurs and many other living things during the Cretaceous–Paleogene extinction event was caused by the impact of a large asteroid on the Earth. Prior to 2013, it was commonly cited as having happened about 65 million years ago, but Renne and colleagues (2013) gave an ...
Raymond B. Cowles proposed that the dinosaurs went extinct when Earth's climate became so hot and dry that it affected the ability of male dinosaurs to produce sperm cells. [23] 1946. Edwin Harris Colbert and others proposed that the dinosaurs went extinct when Earth's climate became too hot and dry to support them. [23] 1949
Albertosaurus (/ ælˌbɜːrtəˈsɔːrəs /; meaning "Alberta lizard") is a genus of large tyrannosaurid theropod dinosaur that lived in northwestern North America during the early to middle Maastrichtian age of the Late Cretaceous period, about 71 million years ago. The type species, A. sarcophagus, was apparently restricted in range to the ...
Parasaurolophus (/ ˌ p ær ə s ɔː ˈ r ɒ l ə f ə s,-ˌ s ɔːr ə ˈ l oʊ f ə s /; meaning "beside crested lizard" in reference to Saurolophus) [2] is a genus of hadrosaurid "duck-billed" dinosaur that lived in what is now western North America and possibly Asia during the Late Cretaceous period, about 76.9–73.5 million years ago. [3]