An asteroid of apocalyptic proportions is likely what killed off the dinosaurs 66 million years ago. But why that particular event spurred the final blow has remained unclear. After all, throughout the dinosaurs’ 150-million-year reign, they’d endured worse calamities, such as volcanic eruptions from the massive Deccan Traps. “Compared with this volcanic catastrophe, the Chicxulub impact is a much lesser catastrophe,” geophysicist Gerta Keller told National Geographic.
Steve Brusatte, a paleontologist at Edinburgh University, and an international team of researchers reviewed the evidence and found that the dinosaurs were simply in the wrong place at the wrong time. Had the asteroid hit five million years earlier or later, they might’ve survived.
Here’s Ian Sample, writing for The Guardian:
The scientists’ report, published in Biological Reviews, found that while, largely, the dinosaurs were faring well at the time of the asteroid impact, the big plant-eating types, including the horned triceratops and duck-billed dinosaurs, had suffered a loss of biodiversity.
The loss of biodiversity in plant-eating dinosaurs left fewer animals at the bottom of the food chain for larger beasts to prey on.
“The decline made those ecosystems at the very end of the cretaceous [period], when the asteroid hit, considerably more vulnerable to collapse than those ecosystems that existed even a few million years before,” said Brusatte. “There is strong reason to believe that if the asteroid had hit a few million years earlier dinosaurs would have been better able to cope.”
And as the saying goes, what doesn’t kill you makes you stronger. The team argued that if the asteroid hadn’t hit, dinosaurs would have recovered from their brief biological weaknesses, virtually wiping out the possibility of animal life and human civilization as we know it. In other words, we definitely wouldn’t be here.
The finding reveals the importance of biodiversity in shielding against unpredictable events. If we can’t deflect incoming asteroids, we’ll at least need to be prepared to face the risks—both technologically and biologically.