A new study has established a direct connection between birds evolution and dinosaur. It shows that the familiar anatomical features of birds like their feathers, wings and wishbones – all first evolved piecemeal in their dinosaur ancestors over tens of millions of years. After a fully functioning bird body shape was complete, a burst of evolution occurred and produced thousands of bird species.
The scientists used the existing fossil record and several recent finds of feathered dinosaurs to draw the connection. Steve Brusatte, a paleontologist at the University of Edinburgh, Scotland, along with his colleagues went through the examination of 850 body features of 150 extinct species of bird and then compared them against their dinosaur ancestors.
They finally developed a complete comprehensive family tree showing how the features evolved over time until the dinosaurs finally took flight.
The team of researchers included Swarthmore College Associate Professor of Statistics, Steve C Wang.
The researchers concluded that the evolution of of birds some 150 million years ago took place gradually, as some dinosaurs became more bird-like along with time.
“The evolution of birds from their dinosaur ancestors was a landmark in the history of life,” said Wang.
“This process was so gradual that if you travelled back in time to the Jurassic, you’d find that the earliest birds looked indistinguishable from many other dinosaurs,” Wang said.
That makes it hard to make a dividing line in a family tree of birds and dinosaurs, researchers say.
“There was no moment in time when a dinosaur became a bird, and there is no single missing link between them,” says Brusatte. “What we think of as the classic bird skeleton was pieced together gradually over tens of millions of years.”
The new findings support a theory put forth by George Gaylord Simpson dating to the 1940s, which proposed that the emergence of new body shapes in groups of species could result in a surge in their evolution.
While the label of “bird” is arbitrarily applied, but the researchers suggests that the feathered fossil Archaeopteryx might be considered as the first of the group.
“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,” says study co-author Graeme Lloyd of the University of Oxford in England.