Anonymous sent us this...
Hi, I'm a 15 year old high school student. I have a question about birds and dinosaurs.
Dinosaurs evolved into birds right? A friend of mine doesn't think that could be true, because bird lungs are so different from any other animals. So my question is, how similar are dinosaur lungs with bird lungs?
There is now overwhelming evidence that dinosaurs did indeed evolve into birds. This includes dinosaurs having light bones, fused clavicles and a special bone in the wrist called the semi-lunate carpel which allows extended movements and ultimately flapping flight (not to mention feathered dinosaurs like the one pictured!). In fact you can trace so-called bird characteristics right back through the theropod dinosaurs. There are as yet no fossilised dinosaur lungs so we have to use other evidence to reconstruct what their lungs might have been like.
The strongest evidence is that air sacs which are found in the bones of dinosaurs are very similar to those in modern birds. Dinosaurs and birds also have uncinate processes on their ribs (little backwards pointing extensions) which we believe is further evidence for a bird like respiratory system in theropod dinosaurs as they make the ribs move in a similar manner in both.