New Discovery Sheds Light on Bird Evolution
Up until a few days ago it was a commonly held belief that modern birds evolved from theropod dinosaurs such as the tyrannosaurus or allosaurus. Now new evidence has been found in favour of the theory that birds evolved separately on a parallel path to dinosaurs.
The discovery may be new, but the evidence has been there all along. Simply put, it is virtually impossible for birds to have evolved from dinosaurs. Researchers at the Oregon State Univserity (OSU) in the US pinpointed the largest significant difference in their skeletal structures – their thigh bones – as proof of this fact. Up until now the relatively fixed position of the bird’s thigh bone and the role that it plays in keeping this creature alive has gone largely unnoticed. While virtually every other land animal has a moveable thigh bone, the bird’s thigh bone, or femur, is largely fixed, making them ‘knee runners’. What is most remarkable about this feature is that it is fundamental to the continued functioning of the animal; it is the fixed position of the femur and other bird bones that keeps their air-sac lung from collapsing when the bird inhales oxygen.
Research has revealed that warm-blooded birds need about 20 times more oxygen than do reptiles which are cold-blooded. As such, they have a unique lung structure which allows for a much higher rate of gaseous exchange and activity. It is this soft and delicate structure which is carefully protected by the fixed skeletal structures that surround the lungs.
According to Devon Quick, an OSU instructor of zoology, their unusual thigh complex and the way it supports the lungs is “fundamental to bird physiology.” Quick noted that “It’s really strange that no one realized this before. The position of the thigh bone and muscles in birds is critical to their lung function, which in turn is what gives them enough lung capacity for flight.” This only adds to other evidence that birds likely did not evolve from dinosaurs – such as the feathers, wings, bones and unique locomotion and lung system that is peculiar to birds – and supports the relatively new theory that they evolved separately on a parallel path to these extinct creatures.