Of the law describes an epoch of the earth's history, which began about 201 million years ago and lasted about 55 million years. The scientists subdivide the Jura today with the lower, middle and upper Jurassic in three series, which are assigned a total of eleven stages. The name of this era goes back to the German naturalist Alexander von Humboldt, who coined the term in 1795. Humboldt referred to his naming on sedimentary rocks from the Jura mountains, which originate from this period and as deposits of the Tethysmeeres, which separated Laurasia from Gondwana emerged.
The climate was characterized in the Jurassic as in the Triassic of mild to hot temperatures worldwide, the humidity was significantly higher compared to the previous era. Evidence of ice masses close to the poles also does not exist for icing inland of the continents. In today's Europe, for example, average temperatures of about 25 ° C prevailed in the lower Jurassic, but these fell to a maximum of 18 ° C in the further course of this epoch. Precipitation increased and temperatures dropped gradually.
The supercontinent Pangea broke up in the Jura, as the large land masses Laurasia and Gondwana moved away from each other again and slowly fell apart. In between, some large seas formed, which significantly influenced the climatic conditions, as they led to more precipitation and associated lower temperatures. Between Europe and Africa, today's Mediterranean emerged. North America and Europe also shared what the emergence of the Atlantic Ocean entailed.
Flora and Fauna (plants and animals):
The higher precipitation and associated humidity led to the expansion of Jura plant life to areas that were still characterized by dry desert landscapes in the Triassic period. The interior of the continents produced dense forests that were not only characterized by high tree growth, but also by low horsetails and ferns growing close to the ground. The vegetation was characterized in the Jurassic thanks to the precipitation of an unprecedented biodiversity. The lush tropical forests in the warmer zones now showed more and more flowering plants. The banks of the numerous inland waters were densely overgrown. In the Jura, the first cypress trees and the room pine trees, which today are popular as ornamental plants, appeared under the nude vines. Even primitive first forms of the later widespread bedecktsamigen plants, which today comprise a large part of all plants, found their origin in the Jura. In the oceans, however, the flora was still largely characterized by red and brown algae and rock-forming species of algae.
In terms of wildlife, the Jurassic is especially important as time of dinosaurs. Through the lush vegetation large herbivorous dinosaurs such as Brachiosaurus could spread with his long neck more and more. These species, which lived mainly in large herds, could easily reach the leaf-rich treetops and thus had a huge advantage over smaller dinosaurs. Large carnivorous species also flourished in the Jurassic and hunted down large herbivores. Millipedes and insects were now represented in an infinite biodiversity near the ground captured smaller predators mainly insects, lizards and small mammals like the ancestor of today's beaver. As a direct forerunner of the birds Archeopteryx also appeared alongside other pterodactyls in the Jurassic. In brackish water, in lakes and rivers, crabs, which previously inhabited exclusively the oceans, spread more and more.