The meteorite that is largely blamed for killing off the dinosaurs may have helped forests bloom.
The 6-mile-long hunk of space rock that hit the Yucatan peninsula about 66 million years ago may have wiped out evergreen plant populations, but not as many deciduous ones, PLOS reported. Researchers from the University of Arizona have hypothesized the properties of deciduous plants made them better able to respond to the rapidly changing climate following the asteroid strike.
To make their findings researchers applied biomechanical formulas to thousands of fossilized leaves of angiosperms, which are flowering plants excluding conifers. The research allowed the scientists to reconstruct the ecology of a plant community that thrived during a 2.2 million-year period after the disaster.
"When you look at forests around the world today, you don't see many forests dominated by evergreen flowering plants," the study's lead author, Benjamin Blonder said. "Instead, they are dominated by deciduous species, plants that lose their leaves at some point during the year."
The leaf fossil collection contained 1,000 samples collected from a location in southern North Dakota, embedded in rock layers known as the Hell Creek Formation, which back at the end of the Cretaceous was a lowland floodplain.
"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," Blonder said. "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."
The study provides evidence of a shift from slow-growing plants to faster-growing species; it could also shed light on modern phenomena such as why rainforests are dominated by deciduous plants.
"There is a spectrum between fast- and slow-growing species," Blonder said. "There is the 'live fast, die young' strategy and there is the 'slow but steady' strategy. You could compare it to financial strategies investing in stocks versus bonds." The analyses revealed that while slow-growing evergreens dominated the plant assemblages before the extinction event, fast-growing flowering species had taken their places afterward.
The findings were published Sept. 16 in the journal PLOS Biology.
