The widely accepted hypothesis of how the dinosaurs perished 66 million years ago involved a violent impact between Earth, and a meteorite, followed by a global winter during which the atmosphere was clogged by dust and debris.
The extinction that occurred 202 million years ago, however, that wiped out the large reptiles that had previously governed the globe and seemingly prepared the way for dinosaurs to take over, is far more obscure and less well-known.
Why did dinosaurs survive when other animals perished during the so-called Triassic-Jurassic Extinction, and what was the cause?
Dinosaurs took over amid ice
(Photo : ISAAC LAWRENCE/AFP via Getty Images)
The Triassic Period, which preceded the extinction, and the succeeding Jurassic Period, which ushered in the age of dinosaurs, are both known to have been hot and muggy overall, as per ScienceDaily.
Recent research, however, challenges the notion that dinosaurs preferred heat, providing the first concrete proof that Triassic dinosaur species, at the time a small group confined mostly to the polar areas, often experienced cold conditions there.
Dinosaur footprints and peculiar rock shards that could only have been left behind by ice are the unmistakable signs.
According to the study's authors, cold snaps that were already occurring at the poles moved to lower latitudes during the extinction, eradicating the coldblooded reptiles.
Because they were already suited, dinosaurs escaped the evolutionary bottleneck and expanded.
According to Paul Olsen, a geologist at Columbia University's Lamont-Doherty Earth Observatory and the study's primary author, dinosaurs were there during the Triassic period undetected all the while.
Their eventual domination rested on a pretty easy strategy. They were essentially creatures accustomed to the cold.
They were prepared when it started to become chilly everywhere, unlike other animals.
The report was just released in the journal Science Advances and is based on recent excavations in the isolated desert of northwest China's Junggar Basin.
Dinosaurs are believed to have initially evolved during the Triassic Period, some 231 million years ago, in temperate southern latitudes, when the majority of the planet's surface was united together in a single enormous continent known as Pangaea by geologists.
By 214 million they had reached the far north.
Over three-quarters of all terrestrial and marine species on the planet, including all large reptiles and corals, were extinct at the end of the Triassic epoch over a geologically brief period of perhaps a million years.
Some burrowing species, such as turtles, as well as a few early mammals, survived.
Although it is unknown exactly what occurred, many experts believe that it was caused by a succession of enormous volcanic eruptions that may have lasted for hundreds of years at a time.
Around this period, Pangaea began to fragment, creating the Atlantic Ocean and dividing the modern-day Americas from Europe, Africa, and Asia.
Also Read: Scientists Find Increasing Tell-Tale Signs of an Upcoming Mass Extinction
Triassic mass extinction
Roughly 76% of all marine and terrestrial species as well as about 20% of all taxonomic groups perished during the end-Triassic extinction, also known as the Triassic-Jurassic extinction, which occurred between 252 million and 201 million years ago, as per Britannica.
The end-Triassic extinction is regarded to have been a crucial turning point that led to dinosaurs predominating among terrestrial creatures on Earth.
Of the five great extinction episodes that have occurred throughout geologic time, this one is the fourth most severe.
Even though this extinction was less severe than its counterpart at the end of the Permian Period, which took place about 50 million years earlier and resulted in the extinction of more than 95% of marine species and more than 70% of terrestrial ones it did cause drastic declines in some living populations.
Ammonoids and conodonts, two taxa that are crucial indicator fossils for determining the relative dates of different strata in the Triassic System of rocks, were notably impacted by the end-Triassic extinction.
Conodonts and a large number of ceratitids ammonoids did indeed go extinct.
Only the phylloceratid ammonoids managed to live, and it was they who later in the Jurassic Period unleashed enormous radiation on cephalopods.
Additionally, several families of gastropods, bivalves, brachiopods, and marine reptiles became extinct.
On land, a large portion of the vertebrate fauna vanished, however mammals, fishes, crocodiles, turtles, dinosaurs, pterosaurs, crocodiles, and turtles were mostly unaffected by the change.
In reality, a lot of experts agree that dinosaurs were able to swiftly fill ecological gaps created by the end-Triassic mass extinction on land.
Related article: Scientists Warn Decline in Animal Biodiversity Hints 6th Mass Extinction Has Started
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