Birds are descendants of some dinosaurs, and now some paleontologists believe they know how the reptiles evolved into the avians we see today.
Dinosaurs did not develop into birds in one swift transformation, but evolved into the flying creatures one small step at a time, according to a new study. Researchers pieced together the most comprehensive family tree ever constructed of the group of animals that led from carnivorous dinosaurs to modern birds.
Feathers, already found on the bodies of many dinosaur species, became more common among the animals as their wings developed over the course of tens of millions of years. Once these evolutionary changes had been established, the animals quickly developed into thousands of new bird species.
"It's basically impossible to draw a line on the tree between dinosaurs and birds. [But, once the first avians evolved], something was unlocked, and [birds] began to evolve at a supercharged rate," said Steve Brusatte, paleontologist from the University of Edinburgh and co-author of an article announcing the findings.
Researchers closely examined over 850 body features in 150 species of extinct birds and dinosaurs. This data allowed them to construct a detailed family tree, leading from bird-like dinosaurs to the earliest avian species. They found these changes started to develop around 150 million years ago, and the two groups of animals were similar to each other.
The evolution of dinosaurs into birds has been accepted by paleontologists for several decades. However, the differences between the two groups of animals appear so great than many people, including scientists, believed that there had to be a "missing link." Over the last 20 years, paleontologists have uncovered several examples of feathered dinosaurs, many of which were found in China. This suggested that dinosaurs may have taken a significant amount of time to evolve into birds.
The Archaeopteryx is often considered the earliest bird, although the species possessed many characteristics that reveal its dinosaur heritage. However, paleontologists believe that other species of dinosaurs may have also been capable of powered flight, one of the defining characteristics of birds.
"It is particularly cool that it is evidence from the fossil record that shows how an oddball offshoot of the dinosaurs paved the way for the spectacular variety of bird species we see today," Graeme Lloyd, another co-author of the study and a paleontologist at the University of Oxford, told the press.
George Gaylord Simpson, a 20th century paleontologist, developed a theory in the 1940s that radical changes in body plans cause bursts of evolution. His theory is supported by the latest research.
Study of the evolution of animals from dinosaurs into birds was detailed in the journal Current Biology.