Most of us have heard of the giant asteroid impact, and the possibility that volcanoes played a role is also well-known. But a complementary school of thought contends that neither of these two events gives us the full story. Rather, some researchers say the dinosaur lineage was slowly pruning itself for many millions of years prior to the KT-boundary. Until now, this idea has seen limited scientific support.
“Previous studies were quite simple,” Manabu Sakamoto, a paleontologist at the University of Reading and lead author on the new study told Gizmodo. “They counted the number of [dinosaur] species around at each age or time interval to see which ones were peaking or troughing when. To be honest, it’s not a very statistical approach.”
Sakamoto and his colleagues used a more rigorous procedure, measuring the number of times new dinosaur species emerged (so-called “speciation events”) throughout geologic history. Over the Triassic and Jurassic, dinosaur diversity was on the rise, but by the early Cretaceous, speciation had begun to plateau. By the mid to late-Cretaceous, the rate of dinosaur evolution had taken a sharp downturn. It would continue to fall for millions of years before the Chixculub impact.
“New species weren’t being produced as fast as species were going extinct,” Sakamoto explained. “That made the dinosaurs vulnerable to drastic environmental changes—especially something like an apocalypse.”
- More Here
“Previous studies were quite simple,” Manabu Sakamoto, a paleontologist at the University of Reading and lead author on the new study told Gizmodo. “They counted the number of [dinosaur] species around at each age or time interval to see which ones were peaking or troughing when. To be honest, it’s not a very statistical approach.”
Sakamoto and his colleagues used a more rigorous procedure, measuring the number of times new dinosaur species emerged (so-called “speciation events”) throughout geologic history. Over the Triassic and Jurassic, dinosaur diversity was on the rise, but by the early Cretaceous, speciation had begun to plateau. By the mid to late-Cretaceous, the rate of dinosaur evolution had taken a sharp downturn. It would continue to fall for millions of years before the Chixculub impact.
“New species weren’t being produced as fast as species were going extinct,” Sakamoto explained. “That made the dinosaurs vulnerable to drastic environmental changes—especially something like an apocalypse.”
- More Here
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