The extinction of the dinosaurs wasn’t just caused by a giant asteroid falling out of the sky, says a new study in the scientific journal, Biological Reviews; it was timing.
Experts now believe that if that 6.2 mile wide hunk of space rock had hit the Earth a few millions years earlier or later, the effects wouldn’t have been so colossal.
Ten scientists say the dinosaurs were victims of “colossal bad luck” more than anything else. When the giant asteroid slammed into what is now present-day Mexico, it doomed the dinosaurs because the environment was already in a state of extreme environmental disorder including massive volcanic eruptions, raging sea level changes and major shifts in worldwide temperatures.
Speaking with the New York Daily News, Paleontologist Steve Brusatte of the University of Edinburgh said:
“I think there is a perception that the asteroid hit an idyllic lost world of dinosaurs, but it hit a world that was in flux. It made their food webs more vulnerable to collapse, so it made dinosaurs more susceptible when the asteroid hit. So maybe if the asteroid hit a few million years earlier it wouldn’t have been so devastating.”
The changing environment Brusatte talks about when he says a “world in flux” would have led to a lack of diversity among the large, plant-eating dinosaurs on which the other dinosaurs dined. That, in turn, weakened the food chain as a whole.
When the food chain collapsed, first one kind of dinosaur died out, which then caused another to die out, and another, and so on. The only ones left, according to the report, were the winged dinosaurs, and they were the ones that evolved into birds.
Another misconception: That the dinosaurs died out extremely quickly… or very slowly. They actually died out quickly, but on a cosmic timeline.
Brusatte told CBS News,
“The extinction was abrupt, happening within a few tens of thousands to hundreds of thousands of years, or even quicker. Dinosaurs weren’t wasting away for tens of millions of years.”
So the extinction was quick, but not quick as in days or decades or centuries.
Researchers that worked on the study said that had the meteor hit a few million years earlier when a richer and more diverse population of herbivore dinosaurs inhabited North America or a few million years later when the plant eaters had recovered some diversity, the extinction of the dinosaurs might have been prevented.
The study, according to researchers, indicates a cautionary tale we can learn from the death of the dinosaurs: In diversity, there is strength.
“When you mess with diversity,” Brusatte said, “you can be even more susceptible to a knockout blow.”