User:Jonathan W/histJan06/Dinosaur
From Wikipedia, the free encyclopedia
Dinosaurs are vertebrates whose characteristics range from reptile-like to bird-like. Dinosaurs dominated the terrestrial ecosystem for over 160 million years from around 230 million years ago until 65 million years ago, at the end of the Cretaceous period, when all non-avian dinosaurs became extinct. Dinosaurs still exist today in the line of birds (avian dinosaurs). Knowledge about dinosaurs comes from both fossil and non-fossil records, including fossilized bones, feces, trackways, gastroliths, feathers, impressions of skin, internal organs and soft tissues. Dinosaur remains have been found on every continent on Earth, including Antarctica. This shows that all land masses were at one time connected in a super continent, called Pangaea, due to the fact that numerous fossils of the same species have been found on completely different continents. Pangaea began to break up during the Triassic period around 230 million years ago.
- For other uses, see Dinosaur (disambiguation).
Dinosaur Temporal range: Triassic – Cretaceous | |
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Replica of Tyrannosaurus rex at the Senckenberg Museum. | |
Extinct / Fossil | |
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Superorder: | Dinosauria Owen, 1842 |
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Since the first dinosaur was recognized in the 19th century, their mounted, fossilized skeletons have become major attractions at museums around the world. Dinosaurs have become a part of world culture and remain consistently popular, especially among children. They have been featured in best-selling books and blockbuster films such as Jurassic Park, and new discoveries are regularly covered by the media. The term is also used informally to describe any prehistoric reptile, such as the pelycosaur Dimetrodon, the winged pterosaurs, and the aquatic ichthyosaurs, plesiosaurs, and mosasaurs, though none of these are dinosaurs.
The on-going dinosaur renaissance began in the 1970s and was triggered, in part, by John Ostrom's discovery of Deinonychus, an active, vicious predator that may have been warm-blooded (homeothermic), in marked contrast to the prevailing image of dinosaurs as sluggish and cold-blooded. Vertebrate paleontology has also become a global science, with major new discoveries in previously unexploited regions, including India, South America, Madagascar, Antarctica, and most significantly the amazingly well-preserved feathered dinosaurs in China, which have further solidified the link between dinosaurs and their living descendants, modern birds. The widespread application of cladistics, which rigorously analyzes the relationships between biological organisms, has also proved tremendously useful in classifying dinosaurs, which are still known from an incomplete fossil record.