Thriving in a Series of Sudden Global Chills That Killed Competitors:
Many of us know the conventional theory of how the dinosaurs died 66 million years ago: in Earth's fiery collision with a meteorite, and a following global winter as dust and debris choked the atmosphere. But there was a previous extinction, far more mysterious and less discussed: the one 202 million years ago, which killed off the big reptiles who up until then ruled the planet, and apparently cleared the way for dinosaurs to take over. What caused the so-called Triassic-Jurassic Extinction, and why did dinosaurs thrive when other creatures died?
We know that the world was generally hot and steamy during the Triassic Period, which preceded the extinction, and during the following Jurassic, which kicked off the age of dinosaurs. However, a new study turns the idea of heat-loving dinosaurs on its head: It presents the first physical evidence that Triassic dinosaur species—then a minor group largely relegated to the polar regions—regularly endured freezing conditions there. [...]
"Dinosaurs were there during the Triassic under the radar all the time," said Paul Olsen, a geologist at Columbia University's Lamont-Doherty Earth Observatory, and lead author of the study. "The key to their eventual dominance was very simple. They were fundamentally cold-adapted animals. When it got cold everywhere, they were ready, and other animals weren't."
[...] How did they do it? Evidence has been building since the 1990s that many if not all non-avian dinosaurs including tyrannosaurs had primitive feathers. If not for flight, some coverings could have used for mating display purposes, but the researchers say their main purpose was insulation. There is also good evidence that, unlike the cold-blooded reptiles, many dinosaurs possessed warm-blooded, high-metabolism systems. Both qualities would have helped dinosaurs in chilly conditions.
[...] The findings defy the conventional imagery of dinosaurs, but some prominent specialists say they are convinced. "There is a stereotype that dinosaurs always lived in lush tropical jungles, but this new research shows that the higher latitudes would have been freezing and even covered in ice during parts of the year," said Stephen Brusatte, a professor of paleontology and evolution at the University of Edinburgh. "Dinosaurs living at high latitudes just so happened to already have winter coats [while] many of their Triassic competitors died out."
Journal Reference:
Paul Olsen, Jingeng Sha, Yanan Fang, et al., Arctic ice and the ecological rise of the dinosaurs [open], Sci Adv, 8, 26, 2022. DOI: 10.1126/sciadv.abo6342
(Score: 1) by Runaway1956 on Friday July 08 2022, @03:09PM (1 child)
Feathered or not, it would take time to adapt from an ice covered world to tropical rain forest, or vice versa. Animals that have traditionally been valued for their thick wool pelts don't thrive when transplanted to equatorial climates. Nor do monkeys and parrots adapt well to arctic winters. Penguins travel thousands of miles from Antarctica, but I don't think they go all the way to the equator and steamy rain forests. Those kind of drastic changes take generations of adaptation.
“I have become friends with many school shooters” - Tampon Tim Walz
(Score: 3, Interesting) by Anonymous Coward on Friday July 08 2022, @11:47PM
The age of dinosaurs lasted about 175 million years, so they had plenty of time. And, it's hard to believe that the climate was constant during that entire time, so it would seem obvious that they did adapt.
Of course, during that time, thousands of species of dinosaurs died out, but were replaced by other dinosaurs. It's worth noting that Tyrannosaurus Rex is closer in time to us than it was to Apatosaurus (formerly Brontosaurus).
And about penguins... they first evolved before Antarctica was ice-covered, when it was still covered with forests. They must have evolved for the current conditions as the climate changed over the last 40 million years or so.