Last updated May 25, 2018 at 10:47 am
Only those living on the ground survived the mass extinction.
It was survival of the lowest when an asteroid struck the Earth 66 million years ago, wiping out non-avian dinosaurs.
Researchers from the UK and the US believe the only birds to survive the Cretaceous-Paleogene (K-Pg) mass extinction event lived on the ground. Tree-dwelling birds were wiped out when the asteroid’s impact destroyed forests that took hundreds or even thousands of years to recover.
A team led by Daniel Field from the University of Bath’s Milner Centre for Evolution examined multiple lines of evidence, including the plant fossil record and the ecology of ancient and modern birds.
“We concluded that the devastation of forests in the aftermath of the asteroid impact explains why tree-dwelling birds failed to survive across this extinction event,” he said. “The ancestors of modern tree-dwelling birds did not move into the trees until forests had recovered from the extinction-causing asteroid.”
Global forests collapsed
Analysis confirmed that global forests collapsed in the wake of the asteroid’s impact. The researchers then used the evolutionary relationships of living birds and their ecological habits to track how bird ecology has changed over the course of their evolutionary history.
Those analyses showed that the most recent common ancestor of all living birds – and all bird lineages passing through the extinction event – most likely lived on the ground.
By contrast, many birds that lived at the end of the age of dinosaurs exhibited tree-dwelling habits. But those species didn’t survive the K-Pg to give rise to any of the modern-day birds we know now.
“Today, birds are the most diverse and globally widespread group of terrestrial vertebrate animals; there are nearly 11,000 living species,” Field said.
“Only a handful of ancestral bird lineages succeeded in surviving the K-Pg mass extinction event 66 million years ago, and all of today’s amazing living bird diversity can be traced to these ancient survivors.”
The authors say their findings illustrate the fundamental influence of major events in Earth’s history on the evolutionary trajectories of major groups of organisms. They plans to continue to explore the precise timing of forest recovery and the early evolutionary radiation of birds.
The paper published in Current Biology.
