The asteroid that wiped out the dinosaurs at the end of the Cretaceous period wiped out much of life on Earth. And while we know how that story goes, a team of scientists is now adding a new chapter. One defined by flowers. In fact, scientists say that the seminal space rock that bathed Earth in Dino’s death is precisely what allowed our home planet to first host the lush and flourishing rainforests we know today.
The team of scientists, working at the Smithsonian Tropical Research Institute (STRI) in Panama, set out to figure out how rainforests change after drastic ecological disturbances. The Chicxulub Impactor, which killed 45% of the plants in what is now Colombia and engulfed the world in darkness, was a perfect opportunity to meet.
Don Davis / NASA
To study the changes, the scientists looked at tropical plant fossils from sites in Central and South America; including more than 50,000 pollen fossils and 6,000 leaf fossils, both before and after impact. About the comparison? The team found that the dinosaur killer transformed scattered, coniferous-rich rainforests into the densest and tallest rainforests today; the same ones that are full of vibrant technicolor bromeliads and hanging orchids.
The scientists, who described their findings in a study recently published in the journal Science (coming in via BBC News), they say the fossil record implies that the forest canopy in the American tropics evolved from relatively open to closed and stratified. In turn, they say this led to increased vertical stratification. And, consequently, a greater diversity of forms of plant growth.
The three central theories that scientists have that explain this change have to do with both the impact of the asteroid and the absence of dinosaurs. Scientists say the first theory is that dinosaurs kept their forests “open” by feeding and moving through them. The second: the ash that falls from the impact enriched the tropical soils, giving an advantage to faster-growing flowering plants. And finally, that the preferential extinction of the most trusting species allowed flowering plants to dominate.
“Our study follows a simple question: How do rainforests evolve?” Monica Carvalho, a botanist and lead author of the study, said in a STRI news release. “The lesson learned here is that under rapid disturbances, geologically speaking, tropical ecosystems don’t just bounce back; they are replaced and the process takes a long time. “
Featured Image: Kirt Edblom
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