At the end of Ordovician about 439 million years ago, due to the global climate cooling, the earth entered the Andean-Saharan Ice Age. At that time, the sea level dropped sharply and a large number of marine life died. About 85% species became extinct at that time.

(2) Devonian species extinction

From the late Devonian to the early Carboniferous, about 365 million years ago, it was known that the mantle plume in the central Pacific ejected a large amount of volcanic ash and greenhouse gases, which led to the sea level drop and the drastic climate change, and marine life was once again extinct, and about 82% of marine species were extinct.

(3) Permian mass extinction

About 250 million years ago, about 96% species on the earth became extinct, which was the most serious mass extinction. Scientists believe that this extinction was caused by a series of reasons, such as climate warming, desert expansion, volcanic eruption and sea level rise.

(4) Triassic mass extinction

About 200 million years ago, in the late Triassic, the sea level rose, causing a large area of anoxic seawater. About 76% species became extinct, reptiles suffered heavy losses, and many marine life disappeared.

(5) Cretaceous species extinction

65 million years ago, at the end of Cretaceous, this mass extinction was the second largest extinction in the history of the earth, and about 75%-80% of species were extinct, announcing the disappearance of dinosaurs that had ruled the earth for a long time since Jurassic.