Meteor that killed off dinosaurs also helped create changing colors of fall, researchers find

LONDON - MARCH 18: An adult Tyrannosaurs Rex robotic dinosaur performs in the O2 arena ahead of the forthcoming European leg of the live show 'Walking With Dinosaurs' on March 18, 2009 in London, England. The live arena show, which has already toured throughout North America, tours the UK from July 2009. The Â£10 million show features 15 mechanical life-sized dinosaurs and is based upon the hit BBC TV series of the same name. (Photo by Oli Scarff/Getty Images) (2009 Getty Images)

The meteor that hit Mexico’s Yucatán peninsula 66 million years ago that is supposed to have spelled the doom for dinosaur life on the planet also may be responsible for a goodly part of the biodiversity visible around the globe today.

Researchers at the University of Arizona say that the massive impact that began what is technically known as the "Cretaceous-Paleogene extinction event," beside wiping out T-Rex and other dinos also destroyed evergreen forests that blanketed the earth – allowing faster-growing deciduous trees to better adapt to the volatile post-apocalyptic environment.

"If you think about a mass extinction caused by catastrophic event such as a meteorite impacting Earth, you might imagine all species are equally likely to die," said the study's lead author, Benjamin Blonder, according PLOS Biology. "Survival of the fittest doesn't apply — the impact is like a reset button. The alternative hypothesis, however, is that some species had properties that enabled them to survive.

Blonder and his colleagues came to their conclusion after studying about 1,000 fossilized plant leaves that were embedded in rock layers known as the Hell Creek Formation in North Dakota, an area which at the end of the Cretaceous period was part of a lowland floodplain that was crisscrossed by river channels.

The Hell Creek collection consists of more than 10,000 identified plant fossils and is now housed primarily at the Denver Museum of Nature and Science.

"Our study provides evidence of a dramatic shift from slow-growing plants to fast-growing species," he said. "This tells us that the extinction was not random, and the way in which a plant acquires resources predicts how it can respond to a major disturbance. And potentially this also tells us why we find that modern forests are generally deciduous and not evergreen."

The research builds on previous work that showed that there was an "impact winter," a dramatic drop in temperature caused by dust sent into the atmosphere from the meteor collision.

"The hypothesis is that the impact winter introduced a very variable climate," Blonder said. "That would have favored plants that grew quickly and could take advantage of changing conditions, such as deciduous plants."

So the next time you find yourself marveling at the colors of the changing leaves in New England or elsewhere, you can thank a deadly meteorite that almost wiped out all life on Earth.