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Why are dinosaurs extinct?
On our planet, there have been many species appear and then disappear, and this is a inevitable stage for biological evolution.However, for dinosaur, such a huge dominant family, why they would suddenly disappear from the earth, People have been searching what happen. What happen when Cretaceous period end in 66 million years ago, so that all dinosaurs and other large of biological death, the scientists have been debated for the reason of their death.
Generally, there are several reasons as scientist mentioned as follows
1.Climate suddenly Change significantly
65 million years ago, Earth’s climate suddenly changes, the temperature dropped significantly, resulting in decreased oxygen content of the atmosphere, so that the dinosaurs could not survive. Some people think that dinosaurs were cold-blooded, they do not have hair or warm organ, unable to adapt to the Earth’s temperature dropped, have been frozen to death.
2.volcanic eruptions
Because volcanic eruptions, a large number of carbon dioxide discharged, causing the Earth’s greenhouse effect urgent bowel so food death. Moreover, volcanic eruptions release a large number of factors such salt, ozone breakdown, harmful ultraviolet radiation the Earth’s surface, causing biological extinction.
3.Orogeny
Orogeny occurred in the late Cretaceous period, many of the dinosaurs could not live regeneration due to lots of marsh. Because the gas changes, the plant has changed, the herbivorous dinosaurs cannot find the new food. Herbivorous dinosaurs disappear result to the carnivorous dinosaurs extinct as well. This extinction process lasted 1,000-2,000 years. Dinosaurs finally disappear on Earth at the end of the Cretaceous.
4.Ocean low tide
According to Barker’s statement, ocean low tide, when the land contact land directly, biological contact with each other, resulting in some kinds of biological extinction, For example, kangaroo. Kangaroos can survive in Europe island with sea fish , but they do not meet the animal species on the South American continent
There are more reasons from different so-called scientists. However, On scdinosaurs, they come back again。
