Dinosaurs sure do look built to survive a mass extinction or two.
In fact, that's not too far off from paleontologists' working theory about why the dinosaurs became ascendant about 200 million years ago in the Late Triassic period. They'd long believed that they had out-competed the crocodile-ancestor crurotarsans, primarily because they had a greater diversity of body sizes and shapes.
But now that theory is coming under new scrutiny. A study publishing today in the journal Science argues that dinosaurs didn't actually occupy more "morphospace" than crurotarsans (see image). In fact, the authors say that there's no evidence that dinosaurs were "fitter" or better adapted to the world at the time than their competitors.
So what explains the rise of the T. rex and his merry friends? The authors don't have an alternative explanation. They say the dinosaurs can thank "historical contingency" (aka, luck) for their survival through the two major extinction events that shaped the world's biosphere during their rise.
"It is likely that dinosaurs were the beneficiaries of two mass extinction events--and some good luck," the University of Bristol authors conclude.
Of course, like a Cinderella team in the NCAA basketball tournament, their luck eventually ran out. The age of the dinosaurs ended during the Cretaceous-Tertiary extinction event about 65 million years ago, opening the door for -- guess who? -- mammals like humans.
See Paper: Science, 2008. DOI: 10.1126/science.1161833
See Also:
- Latest Extinction is the Greatest
- This Week in Dinosaurs: A Mesozoic Vacuum Cleaner, An Accidental Find
- Ancient Dinosaur Flesh Really Just Slime, Say Scientists
- The Rise of the Dinosaurs was Slow Going
- Asteroid Belt Collision Likely Led to Dinosaurs' Death
Image: Courtesy of Stephen Brusatte, University of Bristol
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