Scientists describe ecosystem 66 million years ago for the first time

66 million years ago, the rule of dinosaurs came to an end and mammals on Earth began to rise. At that time, a huge asteroid hit the earth. Dinosaurs were wiped out in this global disaster, but what happened next? How does life recover? The stunning collection of fossils discovered by scientists at the Museum of Nature and Science in Denver has revealed the details of how the world and life recovered after the disaster.

In a recent paper published in Science, scientists describe a collection of fossils excavated in Cosselbravs, central Colorado.

They point to the recovery of life after well-preserved fossils of plants and animals revealed the darkest days on Earth in the crucial 1 million years since the asteroid hit The Earth.

“Sixhundred million years ago, the trajectory of life on Earth changed radically. A huge asteroid destroyed the entire Earth’s ecosystem. Since then the Earth has been shrouded in mystery, and we do not have very good fossils to help understand the evolution of the tree of life. One of the study’s authors, Ian Miller, an paleontologist at the Denver Museum of Nature and Science.

“These fossils tell us about the journey of humans as a species – how we got here. Neil Shubin, a paleontologist at the University of Chicago who was not involved in the study, said.

科学家首次描述6600万年前生态系统

Raccoon-sized Loxolophus and other mammals evolved surprisingly after the mass extinction at the end of the Cretaceous period. Photo credit: HHMI TANGLED BANK STUDIOS

The earliest survivors.

All modern mammals, including humans, can be considered the earliest survivors of the impact.

“One day 66 million years ago, the trajectory of life on Earth changed dramatically. Tyler Lyson, an paleontologist at the Denver Museum of Nature and Science, one of the authors of the newsletter, told The Chinese Journal of Science, “An asteroid bombed our planet, causing the extinction of three-quarters of the creatures. Although it was the worst period of life on Earth, some things survived, including the earliest human ancestors. “

The discovery of fossils of animals and plants has allowed researchers to understand the evolution of life over a million years after the dinosaurs’ extinction, which coincides with the origins of the modern world.

“Our understanding of the consequences of an asteroid’s impact on Earth has been fragmented,” Lyson said. For the first time, these fossils tell us exactly how our planet recovered from this global catastrophe. “

Lyson grew up in fossil-rich North Dakota and, as a child, became interested in the mystery of the dinosaur’s fate. As a teenager, he became a seasoned “dinosaur hunter”.

Where dinosaurs existed and did not exist, there is a well-known pattern: there seems to be no more dinosaurs above a certain limit.

Later, Lyson learned that this boundary layer was also a sign of change in the world: an asteroid hit Earth. A large crater 20 miles deep and more than 100 miles wide on Mexico’s Yucatan Peninsula has fallen from the sky with lava and white-hot glass beads.

The creatures on the ground were scorched and the sky darkened. After that, plants withered, forests collapsed, and all dinosaurs – except birds – went extinct.

Game Changer

For years, Lyson et al. have been looking for vertebrate fossils in areas close to the asteroid impact plane. It wasn’t until 2016 that they discovered the rock above the border.

“That summer, a chance to find the fossils, they were actually lying right before our eyes. Lyson said.

Lyson was inspired by a fossil in a museum collection drawer and a fossil-search technique used by his South African colleagues. Instead of searching for flickering bone fragments in the Denver Basin, he focused on egg-shaped rocks known as “concrete.”

“It’s definitely a moment of light, a game-changer. Lyson said.

Turning on the concrete, Lyson and Miller discovered a miracle: the skulls of early mammalian survivors of the Great Extinction.

“Finding even one skull of this era is a great thing. In fact, much of this era is based on fossil-based tiny fragments, such as mammalian tooth fragments. You may never find the skulls of animals of this period, and that’s what’s rare about them. Miller told China Science Daily.

Over the next few months, researchers unearthed thousands of fossils, including plants, reptiles and 16 different mammal fossils. With these fossils, the researchers pieced together the ecosystem after the “dark moment” and what the animals were living and would breathe.

Life at that time.

George Sparks, chief executive of the museum, said: “Thanks to the expertise, vision and courage of the scientific team, we have a clearer understanding of how the modern mammalian world emerged from the ashes of dinosaurs. “

What is presented is an intricate picture: the resurrection of plant and animal life is intertwined after an asteroid hit Earth.

Combined with a striking record of plant fossils and the discovery of mammalian fossils, the team was able to link thousands of years of warming to global events, including a large amount of volcanic activity on the Indian subcontinent. These events may have shaped the ecosystems of North America that are now non-existent, far beyond the world.

“We documented changes in the landscape after the crash, from a world dominated by palm trees to a world dominated by more diverse trees. We have also seen simultaneous changes in animal species.

Then we link it to changes in ambient temperature, putting all the pieces together and giving a picture of what is happening in the modern world. Miller said.

Anjali Goswami, a paleontologist at the Natural History Museum in London, said: “It wasn’t until the asteroid impact completely destroyed the dinosaurs that mammals exploded with the amazing diversity we see today. “

“The recovery model we saw in Conselbravs is a region’s gold standard, and now we want to see if it’s normal or not.” The exciting thing is that this is not the end of the story, but the beginning of a big thing. Lyson said.

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