Sixty-five million years ago, an asteroid is believed to have crashed into Earth. The impact wiped out huge numbers of species, including almost all of the dinosaurs.
One group of dinosaurs managed to survive the disaster. Today, we know them as birds.
The idea that birds evolved from dinosaurs has been around since the 19th century, when scientists discovered the fossil of an early bird called Archaeopteryx. It had wings and feathers, but it also looked a lot like a dinosaur. More recent fossils look similar.
But these early birds didn’t look the same as modern ones. In particular, they didn’t have beaks: they had snouts, like those of their dinosaur ancestors.
To understand how one changed into another, a team has been tampering with the molecular processes that make up a beak in chickens.
By doing so, they have managed to create a chicken embryo with a dinosaur-like snout and palate, similar to that of small feathered dinosaurs like Velociraptor. The results are published in the journal Evolution.
The team’s aim was to understand how the bird beak evolved, because the beak is such a vital part of bird anatomy. It has been crucial for their success. The 10,000 or more bird species occupy a wide range of habitats, and many have specialised beaks to help them survive.
“Whenever you examine an important evolutionary transformation, you want to learn the underlying mechanism,” says Bhullar.