The asteroid that killed dinosaurs 66 million years ago, also led to the extinction of the first tree-dwelling birds, finds a study. The ground-dwelling birds basically got over and the rest of the birds of today evolved from them. Their findings were published May 24 in the journal Current Biology. Understanding the extreme impact of the event can give scientists insight into the environmental changes that are happening now.
First came the impact itself, with shock waves and tsunamis.
Following the asteroid impact, the intense heat would have caused global wildfires that would've wiped out forests.
"The atmosphere was loaded for a very brief interval of time, and the consequences of that change in atmospheric composition lasted for 100,000 years", MacLeod says.
Not only did the forest canopies collapse, they wouldn't be able to regrow.
The fossil record immediately after the asteroid hit shows the charcoal remains of burnt trees, and then, tons of fern spores, the researchers said. "It talks to the power of collective science, and the significance of the fossil record for comprehending the life in the contemporary world".
The ground-dwelling birds that made it through would not have had a simple presence. They most likely lived off the hardiest grains and seeds that sustained the effect, along with pests.
They eventually diversified into ostriches and their relatives, chickens and their relatives, and ducks and their relatives.
The long-standing question, then, is why certain birds lived while others died in the mass extinction event at the end of the Cretaceous period?
But the ground-dwelling birds that survived carried a lasting legacy beyond the tinamous.
" Today, birds are the most varied and internationally prevalent group of terrestrial vertebrate animals- there are nearly 11,000 living types", Field stated in a declaration.
Today's "amazing living bird diversity can be traced to these ancient survivors". Spores are much smaller sized than seeds, and they can quickly grow in a moist location.
"This fern spike represents evidence of 'disaster flora, ' where pioneer species are rapidly recolonizing open ground, such as seen today when ferns recolonize lava flows in Hawaii or landslides after volcanic eruptions", Bercovici says.
So how long would it take the ferns to thrive?
The researchers painstakingly searched for them in pounds of rock from El Kef, Tunisia, a site that is famous for having well-preserved rock layers that span the time periods both before and after the asteroid impact.
Dr Antoine Bercovici from Smithsonian Institution said birds didn't move back into the trees again until the forests recovered thousands of years later.
"This global catastrophe left such an indelible signature on the evolutionary trajectories of these groups that we can still discern it 66 million years later".
Studying entire paleoecosystems demonstrates how life in the world has actually developed through all the trials and adversities of the past, Dunn stated in an e-mail.
The researchers found that the only birds that survived were ground-dwellers.
"Human activity is causing deforestation on a massive scale", Field said. Jingmai O'Connor, a paleontologist at the Institute of Vertebrate Paleontology and Paleoanthropology in China said, "Forest loss was only one of several factors working in combination that determined which bird lineages survived".