(ORDO NEWS) — At the time of the meteorite fall to Earth, dinosaurs dominated all ecosystems and were not going to die out, writes The Times. Previously, it was believed that by this period, giant reptiles were already in decline.
A comprehensive analysis of the fossil finds has shed new light on the mystery-shrouded last years of dinosaur existence.
His results showed that dinosaurs lived very well on our planet until the moment when an asteroid impact doomed them to extinction.
The question of how well dinosaurs fared before disappearing from the face of the earth about 66 million years ago has been debated in scientific circles for decades.
Now it is generally accepted that the devastating impact of the asteroid decided their fate, but could this block that came from outer space deliver the so-called “blow of mercy” to them, that is, finish off these reptiles doomed to inevitable death?
Some scientists argue that dinosaurs were already in decline when the asteroid hit.
The new study, which is the most comprehensive to date, has led scientists to a different conclusion: Dinosaurs were at their peak at the time of the asteroid impact.
Tyrannosaurus rex skull at the Museum of Natural History in Washington DC
By analyzing hundreds of fossils, scientists have been able to build a picture of how food chains were organized and how the animals involved in them evolved.
Just before the asteroid impact, it was the dinosaurs that dominated all terrestrial ecosystems. There was no indication that they could cede their dominant positions to some other group of sentient beings.
This conclusion contradicts previous studies that have focused on the decline of the largest herbivorous dinosaurs. The new analysis showed that these giant reptiles were simply replaced by smaller species.
The authors of this new study emphasized that dinosaurs have adapted extremely well to their environment. It was this ideal fitness that ultimately determined their extinction.
They failed to survive the impact of an asteroid that covered the entire surface of the Earth in ash, plunging it into a “nuclear winter” that lasted for decades and put an end to ecosystems. Unable to adapt to new conditions, the dinosaurs became extinct.
Another group of animals, namely mammals, showed significantly more flexibility. However, the authors of the study question the idea that throughout the dinosaur era, mammals were timid, mouse-like creatures biding their time in the undergrowth.
The models created by scientists showed that during the heyday of carnivorous dinosaurs, such as the tyrannosaurus rex, the diversity of representatives of the group of mammals grew rapidly.
At the time of the fall of the asteroid, there were already such creatures as Didelphodon among them. This cat-sized animal was probably the most experienced predator in its weight class.
Among the mammals was also a rat-sized creature called Purgatorius, said Alfio Alessandro Chiarenza, author of the study from the University of Vigo. It seems that it was the most ancient relative of modern primates, including humans.
The results of the study showed that mammals did not just fill the niches left after the extinction of the dinosaurs. They were also lucky that while the dinosaurs were still alive, their diet and behavior became more diverse.
In a sense, the first mammals to survive and survive the asteroid impact were “pre-adapted” to the chaos that began on Earth after the impact of the space aggressor, said Steve Brusatte (Steve Brusatte) from the University of Edinburgh, who led the study.
Mammals could eat a wide variety of foods and cope with the temperature fluctuations that began after the asteroid impact. Perhaps this is what distinguished them from dinosaurs of similar size, which were very numerous, but which eventually became extinct.
This study was carried out by an international team of paleontologists and environmentalists who analyzed 1,600 fossils found in North America.
The fossils were used to build models of what food chains and other aspects of the natural world might have looked like during the last few million years of the Cretaceous and the first few million years of the Paleogene after the asteroid impact.
Jorge García-Girón of the University of León in Spain, who also led the study, said the results “help us understand one of paleontology’s age-old mysteries: why all dinosaurs, except birds, died out, while birds and mammals survived.”
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