How 'birds' evolved from dinosaurs

Scientists have found crucial information on how birds evolved with the help of most comprehensive dinosaur family tree ever.

The study showed that the familiar anatomical features of birds, such as feathers, wings and wishbones, all first evolved piecemeal in their dinosaur ancestors over tens of millions of years.

However, once a fully functioning bird body shape was complete, an evolutionary explosion began, causing a rapid increase in the rate at which birds evolved. This led eventually to the thousands of avian species that we know today.

Researchers, led by the University of Edinburgh, examined the evolutionary links between ancient birds and their closest dinosaur relatives by analysing the anatomical make-up of more than 850 body features in 150 extinct species, and used statistical techniques to analyse their findings and assemble a detailed family tree.

Based on their findings from fossil records, researchers said that the emergence of birds some 150 million years ago was a gradual process, as some dinosaurs became ever-more bird-like over time. This made it very difficult to draw a dividing line on the family tree between dinosaurs and birds.

Findings from the study supported a controversial theory proposed in the 1940's that the emergence of new body shapes in groups of species could result in a surge in their evolution.

Dr Steve Brusatte, who led the study, said that a dinosaur never became a bird, and there was no single missing link between them. What they thought of as the classic bird skeleton was pieced together gradually over tens of millions of years. Once it came together fully, it unlocked great evolutionary potential that allowed birds to evolve at a super-charged rate.