Animals became faster and wiser after the mass extinction

According to the study, published Friday (17) in Boundaries in geoscience, after this event, which is the largest mass extinction ever recorded on Earth, predators became more voracious, and prey had to adapt quickly to find new ways to survive. The ancestors of mammals and birds became warm-blooded animals that were able to move faster.

The Great Death occurred at the end of Permian, when almost all life forms on the planet became extinct, with 95% of marine species and 70% of terrestrial species extinct.

What followed was one of the most extraordinary moments in the history of life: the Triassic period 252 to 201 million years ago, which marked a spectacular rebirth of life on earth and in the oceans.

“Everything accelerated,” said Professor Michael Benton of the School of Earth Sciences at the University of Bristol, lead author of the new study. “Today there is a huge difference between birds and mammals on the one hand and reptiles on the other. Reptiles are cold-blooded, which means they do not generate much body heat, and although they can bite very quickly, they have no endurance and cannot live in the cold. »

Feixiang Wu, a researcher at the Beijing Institute of Vertebrate Paleontology and co-author of the paper, says the same thing happened in the oceans. “After the Permian mass extermination, fish, lobsters, gastropods and starfish are exhibiting new hunting styles. They have become faster and stronger than their ancestors.

New ways of hunting appeared after the great death, suggesting that sea creatures that appeared after this time were much faster than their ancestors. Photo: Catmando-

Wu has analyzed fish fossils from the Triassic period in China, including many types of predators, which show that new ways of hunting appeared earlier than previously thought. He encountered modern sharks and the longfish Saurichthys, which was very common in the world at the time, and which was an ambush hunter who lurked in dark shallow seas and darted out to snatch all kinds of prey with his multi-toothed jaws. .

“Other Triassic fish from China were adapted to crush shells,” Wu said. “Several large groups of fish, and even some reptiles, became shell crushers with large layers of teeth. We even found the oldest flying fish in the world, which probably flew away to escape new predators.

The mass extinction has made the animals’ blood warmer

Later Permian land reptiles generally moved slowly and used a kind of extended position, like modern lizards, where the limbs were attached to the sides. When they walked, they probably moved slowly. Already at high speed they could run or breathe, but not both at the same time. It limited your endurance.

“Biologists have long discussed the origin of endothermia, or warm blood, in birds and mammals,” Benton said. “We can trace their origin back to Carbon over 300 million years ago, and some scientists have recently suggested that they were already endothermic at the time. Others say they first became endothermic in the Jurassic, for example, 170 million years ago. since.

But according to Benton, “all possible evidence from the study of cells and even the chemistry of their bones suggests that both groups became warm-blooded after the great mass extinction of the late Permian and early Triassic.”.

In addition, their ancestors were mostly erected in the position at the exact same time. By standing on their limbs, they could take longer strides. This is related to some degree of endothermia, to allow them to move quickly and for extended periods of time.

Previous studies suggest that the ancestors of small and medium-sized trias birds and mammals had some form of thermal insulation in their feathers (in the case of birds) and their fur (in the case of mammals). If this is true – and the new findings seem to confirm it – then all the evidence points to major changes in these reptiles as the world rebuilds after the Great Death.

“Overall, animals accelerated on land and in the oceans, consuming more energy and moving faster,” Benton said. “Biologists call this type of process ‘arms race’, referring to the Cold War. As one side accelerates and becomes more bloodthirsty, so does the other side. This affects competition between herbivores or competition between predators. It also refers to predator prey. conditions – if the predator gets faster, the prey must also stay to escape.

Not only on land but also in water. “As predators have become faster and wiser to attack their prey, sea creatures have had to develop defenses,” Wu said. “Some have thicker shells or developed spine, or have become faster at their escape.”

Benton explains that none of this is new. “The new thing is that we are now discovering that all these events apparently took place at the same time across the Triassic.”

According to him, this underscores a “positive aspect” of mass extinctions. “Mass extinctions were, of course, terrible news for all victims. But the massive purge of ecosystems in this case has given the biosphere plenty of opportunities to rebuild, and it has done so with greater resilience than before the crisis.

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