Jurassic
The Jurassic is a geological system which extends from -199,6 to -145,5 million years.
The stratigraphic layers which define the beginning and the end of Jurassic are well-known, but the exact dates are dubious from 5 to 10 million years. The Jurassic one was named thus by Alexandre Brongniart according to the limestones found in the the Jura. This period of the Mesozoic era follows the Trias and precedes the Crétacé.
The beginning of Jurassic was marked by a massive extinction of species. This period is subdivided in Lias , Dogger and so known Malm under the name of Jurassic inferior, Jurassic average and Jurassic higher.
At the beginning of Jurassic, the Supercontinent Pangée started to be divided into North America, Eurasia and Gondwana. During the Jurassic superior, the Gondwana was divided in its turn into Africa, South America and the Antarctic. Following the example Sorted, it does not seem to have had ground close to the poles there; the climate was hot: there do not exist indices of a Glacial period for this period.
During Jurassic the most advanced forms of life in the seas are the Poisson S and of the Reptile S sailors. New groups such as the Plancton appear. The Ammonite S are very common.
On ground, the reptiles remain dominant. The first birds probably evolved/moved during the Malm time.
In the film Jurassic Park, the dinosaurs contained in the park go back to all the Mesozoic one (Sorted, Jurassic and Cretaceous), and not only of the Jurassic one.
If one takes the Jurassic one within the meaning of populated era of dinosaurs, quote the Allosaure and the Stégosaure .
See too
References
- Alexandre Brongniart, Table of the grounds which compose the bark of the sphere , 1829, p. 223
Simple: Jurassic
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