By Harry Keller
Editor, Science Education
You may have noticed one of the many articles such as this one that cast doubt on the asteroid (or comet) strike that annihilated the dinosaurs. Oh, the asteroid did the job, they say, but it had some help.
Careful examination of North American fossil records strongly suggests that the dinosaur population was under stress from lower than usual herbivore diversity. What say?! There just weren’t as many plant-eating dinosaurs as usual, which means that dinner for the large meat-eaters was a bit harder to come by.
The Earth was undergoing extreme changes 66 million years ago when the great impact took place. Massive volcanic eruptions in what is now India were the result of a collision of the Indian and Asian continental plates. Climate was undergoing change. And dinosaur herbivore diversity was down.
The above was really no big deal. Dinosaurs had been around for well over 100 million years and had survived many environmental challenges. This was just another that would kill off lots of individuals and perhaps a few species. As a whole, the dinosaurs would come roaring back soon enough, however.
The problem was that they were in a very bad position to withstand an enormous asteroid strike. Some scientists liken it to a “perfect storm.” Had the asteroid missed the Earth, dinosaurs probably would be still around, only extending their rule of the Earth by 50% more years. Had the asteroid hit some millions of years earlier or later, the scientists suggest, many dinosaurs would have called it quits, including quite a few species. However, enough would have survived to repopulate the territories emptied and the environmental niches vacated. They probably would have beaten those tiny shrew-like mammals hiding in holes to it and prevented the takeover of the earth by those suckling creatures.
Too bad that we would not have seen these successful dinosaurs today, not because they would not have made it through the intervening 66 million years but because we would not be here.
When you add up all of the things that had to happen over the 4-½ billion lifetime of the Earth in order for humans (intelligent, tool-making animals with the ability to create extensive technology) to appear, you have to shake your heads about the likelihood of ever meeting another such species anywhere nearby in our galaxy, but that’s a discussion to be reserved for another article.