The impact of dinosaur extinct asteroids may have created today's Amazon rainforest

The formation of the rainforest on earth may have originated from the asteroid impact that led to the extinction of dinosaurs, a new study suggests. Using pollen and leaf fossils from Colombia, the researchers explored how asteroid impacts changed the tropical forests of South America.
The impact of dinosaur extinct asteroids may have created today's Amazon rainforest
The asteroid impact 66 million years ago not only led to the extinction of dinosaurs and other life forms, but also led to the replacement of ecosystems


66 million years ago, a 12 kilometer wide space rock hit the earth, causing great changes in the types of vegetation that make up these forests. The team reported their findings in the famous journal Science. "Our team examined more than 50000 pollen fossils and more than 6000 leaf fossils before and after the impact," said study co-author Dr. Monica Carvalho of the Smithsonian Tropical Institute in Panama
Today's asteroids, such as juniper and gymnosperms, are very common in Mexico before the collision. But after the devastating asteroid impact, plant diversity has declined by about 45%, and species extinction is very common, especially seed plants.
The impact of dinosaur extinct asteroids may have created today's Amazon rainforest
Unlike the tropical forests of the late Cretaceous, today's rainforests are very dense and have a thick canopy
In the next 6 million years, the forest gradually recovered, and angiosperms (also known as flowering plants) began to occupy a dominant position. The structure of tropical forests has also changed as a result of this change. In the late Cretaceous period, when dinosaurs were still alive, the trees that made up the forest were widely spaced, and the canopy did not overlap, leaving an open sunlight area on the forest floor. But millions of years after the asteroid impact, the forest formed a thick canopy, making the light to the ground sharply reduced, in the tall trees, dotted with colorful orchids and other flowering plants.
So how did the impact transform the sparse coniferous dominated tropical forest of the dinosaur era into today's tropical rainforest? Based on the analysis of pollen and leaf fossils, the researchers put forward three different explanations. The first explanation is that many dinosaurs usually fed on plants that grew at the bottom of the forest and were used to trampling on them so that the forest was not too dense.
The second explanation is that the deposition of volcanic ash makes the soil throughout the tropics fertile, which is conducive to the rapid growth of flowering plants. The last explanation is that the first extinction of coniferous species creates opportunities for flowering plants to flourish.
The research team said that these views are not mutually exclusive, but may work together to lead to the results we see today. "The lesson from this is that under rapid interference Tropical ecosystems will not only recover, they may also be replaced, and this process will take a long time. "