Massive Impact May Have Doomed the Dinosaurs, But it Jumpstarted Flowering Plants

What may be good for plants may be bad for dinosaurs. It turns out that the massive impact that helped cause dinosaurs become extinct 66 million years ago may have also giving flowering plants the chance they needed to replace slow-growing evergreens.

"When you look at forests around the world today, you don't see many forests dominated by evergreen flowering plants," said Benjamin Blonder, the lead author of the new study, in a news release. "Instead, they are dominated by deciduous species, plants that lose their leaves at some point during the year."

In order to learn a bit more about the transition that occurred in the ancient past, the researchers examined about 1,000 fossilized plant leaves that were embedded in rock layers known as the Hell Creek Formation. At the end of the Cretaceous period, this region was a lowland floodplain crisscrossed by river channels. By applying biomechanical formulae to these fossils, the researchers were able to reconstruct the ecology of a diverse plant community that thrived during a 2.2 million-year period that spanned the impact event.

"If you think about a mass extinction caused by a catastrophic event such as a meteorite impacting Earth, you might imagine all species are equally likely to die," said Blonder. "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."

In this case, the researchers found that slow-growing plants switched over to fast-growing species. In fact, the impact allowed flowering plants to dominate the ecosystem. These plants were able to take advantage of the changing conditions by growing quickly.

In the end, it seems as if the impact didn't just kill the dinosaurs; it also overturned the plant ecosystem at the time and allowed deciduous forests to take advantage and take root. This, in particular, may help explain why the forests of today are dominated by deciduous plants rather than those that are evergreen.

The findings are published in the journal PLOS Biology.