During the Jurassic period, Pangu, a super land mass, really began to split. Cracks in the continental crust formed the Atlantic Ocean, Africa-South America landmass began to split, and India began to move to Asia. The strong tectonic changes around the Pacific Ocean are closely related to the subduction of the Pacific plate to the surrounding continental plates. In the late Jurassic, large-scale transgression occurred all over the world.
The global climate was warm in Jurassic, but there were also differences among tropics, subtropics and temperate zones. The ocean produced by the influx of continental cracks produced humid winds, which brought rainfall to the desert in the original inland, and plants began to extend to the previously barren places. In the middle and early Jurassic, combined with the arid climate in North America, South America and southern Africa in the central and western parts of the ancient land, the climate in northern China was warm and humid, and the climate in the south was tropical and subtropical. In the late Jurassic, the warm and humid areas in northern China shrank, and the south gradually became a dry and hot environment.
Equisetum equisetum, true fern, pine and cypress, ginkgo biloba and arbor fern in Jurassic ferns formed a lush forest, and herbs and ferns covered the ground. Cycas, conifers and ginkgo in gymnosperms are extremely prosperous. Cycas and ferns grow in relatively dry areas, forming a large evergreen Yuan Ye. In Jurassic, the climate around the earth was similar, and the flora tended to be similar. Jurassic ammonites, shell ornaments and shell shapes are increasingly diversified, and bivalves are also very rich. In the late Jurassic, due to geographical movement, marine animals were clearly divided into Tethys area and northern area. There are more than 1000 species of Jurassic insects, including cockroaches, dragonflies, beetles, grubs, tree lice, flies, moths and so on.
Jurassic was the heyday of dinosaurs, which appeared in Triassic, and the extinction occurred at the end of Triassic, and dinosaurs quickly became the rulers of the earth. On land, the main herbivorous vertebrates are protosauropods and ornithopods, as well as small reptiles similar to mammals. In the later period, giant sauropods were the main animals, which could eat both higher plants and lower plants. Dragon feet grind food by swallowing stones. Large theropods, such as Tyrannosaurus rex, prey on herbivores, while small theropods, such as coelenterates and jawbones, prey on small prey and carrion. The new-born multidentate mammals in the early Jurassic belong to herbivorous mammals. Ancient mammals that appeared in the Middle Jurassic are generally considered as the ancestors of marsupials and placental mammals. The most primitive mammal that first appeared in the late Triassic was on the verge of extinction in the late Jurassic.
There are mainly ichthyosaurs in the ocean, in addition to plesiosaurs and short dragons. Animals living in shallow waters also have a group of sea crocodiles whose limbs have evolved into flippers. In the late Jurassic, ichthyosaurs and crocodiles gradually declined. Chondroscleroderma was replaced by whole bone fish in Jurassic. The number of teleosteichthys that appeared in Triassic began to increase in the late Jurassic, but there were fewer species. Pterosaur had an advantage in the air. Early birds appeared, and the famous archaeopteryx, with its bones, teeth, claws, feathered wings and tail, was similar to that of small theropod dinosaurs, which may have evolved from dinosaurs, in addition to the Chinese dragon bird.
There was no extinction event between Jurassic and Cretaceous, and there was no obvious biological evolution characteristics. The extinction of dinosaurs took place at the end of Cretaceous. It is generally believed that the impact of meteorites on the earth caused the extinction of dinosaurs and other creatures, but this view is still controversial.