By Daniel EngberPosted 07.24.2012 at 3:02 pm 53 Comments
Possibly. The trees-down (or “arboreal”) hypothesis has been around for many years, says evolutionary biologist Richard O. Prum of Yale University. Researchers guessed that the scales of tree-dwelling Triassic reptiles elongated into feathers, which helped them leap away from predators. Once the proto-birds could glide, they were en route to avian flight. “It was like one big, crazy hairball of ideas all stuck together,” Prum says.
For years scientists have debated the cause of the mass extinction that killed off the dinosaurs and a slew of other species on Earth 65.5 million years ago. Now, after reviewing 20 years worth of data and research, an international team of scientists concludes that it was a a huge meteorite strike that triggered the extinction.
In the late 1970s, a geophysicist discovered an impact crater in Yucatán, Mexico, and analysis showed the crater's date of origin to be the end of the Cretaceous. Geologic data indicate that the meteorite that produced the Chicxulub crater -- which lies partially buried beneath the Yucatán Peninsula -- was between 10 and 15 kilometers (6 and 10 miles) in diameter and caused an explosion on Earth that was a billion times more powerful than the Hiroshima atomic bomb.