How dinosaur arms turned into bird wings

You can forget Jurassic Park because actually dinosaurs are all around us! And I'm not joking because the fact is that when you see a chirping bird, you're actually looking at a modern dinosaur. Evidence has been growing for some time that our feathered friends are descended from small carnivorous dinosaurs called therapods. For example, the arrangement of bones in a bird's fingers, encased in the wing, is very similar to the bones in fossilised therapods. But there are still some biologists who study early development, as a chick grows in an egg, who aren't convinced by the dinosaur story.Now a new paper from scientists in Chile provides more evidence in favour of dinosaurs - and it all seems to hinge on their wrists. Kat Arney spoke to Paul Upchurch, from UCL's Earth Sciences department, to find out more.