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How the dinosaurs hijacked

Dinosaurs bestrode Mesozoic like a colossal statue. literally.Large sauropods (think about it) Brontosaurus, But 5 times its mass) was the largest animal in history to walk on land. However, this was not always the case in the Mesozoic era. The Mesozoic is composed of three periods: Triassic, Jurassic, and Cretaceous. Best riding like a colossal statue was limited to the Jurassic and Cretaceous. So how did that happen?

When they first appeared, there was clearly nothing special about dinosaurs in the middle of the Triassic. Other groups of large reptiles quarreled with them for the universe on Earth. Their dominance was based on surviving a mass extinction that overcame competition, like that of the mammals that eventually replaced them. Paul Olsen of Columbia University in the United States and Sha Zingen of the Nanjing Institute of Geological Paleontology in China now believe they know what gave them an edge when this happened.It was written by them Science AdvancesAbility to withstand the cold.

For most people, the event that annihilated the dinosaurs (except for the winged feather breeds, more recently known as birds) was the collision of the Earth with a large cosmic rock, either an asteroid or a comet. I agree with you. It was this that signaled the end of the Cretaceous. The end of the Triassic was much longer. This seems to have been caused by a series of large volcanic eruptions associated with the separation of the Old World and the New World when the Atlantic Ocean opened and the Pangea supercontinent collapsed.

Volcanoes release carbon dioxide into the atmosphere, which tends to warm the climate.The Late Triassic was already a period of high CO2 Levels and high temperatures (for example, there are no signs from the days of polar ice caps). Therefore, it is widely believed that extinction was further caused by global warming.

Dr. Olsen, Dr. Sha and his colleagues disagree. They observe that volcanoes also release large amounts of sulfur dioxide, which subsequently form aerosol particles that reflect sunlight back into space and cool things down. According to modeling, the pulse of sulfur dioxide emission could have reduced the average temperature around the world by as much as 10 ° C. Therefore, at the time of the mass extinction, the Arctic would have had a freezing winter. And the team now showed that it was done.

Their evidence comes from the lake deposits of the Junggar Basin in Xinjiang Uygur Autonomous Region. These straddle the Triassic and Jurassic boundaries. Many of the rocks in question are composed of two differently sized particles, indicating that these particles have different origins. Today, this is especially characteristic of sediments in places like the Sea of ​​Okhotsk. There, small grains are carried by the underwater stream to rest areas, and large grains hitchhiking from the shore underneath the broken raft. Researchers’ hypothesis is that lakes in the Junggar Basin will be cold enough in winter, forming surface ice along the coastline.

Years of excavation of Triassic formations around the world show that reptiles of that era were already stratified by latitude. Dinosaurs were abundant and diverse near the poles. Other groups, especially pseudosuchia (today represented by crocodiles and their relatives), preferred a more tropical climate. Dr. Olsen and Dr. Sha believe this reflects the fundamental difference in cold hardiness. Modern bird feathers are now considered to be an enlarged, special version of the much simpler thermal filaments that were ubiquitous in dinosaurs, similar to mammalian hair. Had these possessed, the dinosaurs living near the poles would have been kept warm. There is no evidence that ancient pseudosuchia had an equivalent, and modern crocodile is certainly not.

If the sulfur release caused by the Atlantic lift had the suspected cooling effect of Dr. Olsen and Dr. Sha, it is clear that the dinosaurs shrugged it from the Junggar Basin formations. The coastline of the lake in the Junggar Basin. However, Pseudosuchia could easily succeed as a result. Later, when the eruption stopped, the dinosaurs were able to move to vacant low latitudes and evolve into giant animals loved by natural history museums and film directors. ■■

How the dinosaurs hijacked

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