For my current blogging site, visit the following link:
, Cheers!
Wednesday, January 2, 2013
Tuesday, January 1, 2013
Birds: The Contentious Origin
Birds have been long believed to have evolved from Saurischian dinosaurs, with one particular avian ancestor: Archaeopteryx. A recent study suggests that Archaeopteryx may not be the 'first bird' after all...
Shortly after Charles Darwin published "On the Origin of Species" in 1959, an ancient bird known as Archaeopteryx was discovered in Germany, and quickly became renowned as the missing link between dinosaurs and birds.
- Above: an iconic fossil of Archaeopteryx.
The evidence? Well, Archaeopteryx possesses traits which overlap with both late Saurischian dinosaurs, as well as modern avian species. (In other words, it was, at the time, the most suitable missing link in the chain between dinosaurs and birds) For instance, Archaeopteryx had claws, teeth, a long tail, and a more posterior centre of gravity -- all shared with its dromeosaur ancestors. In addition, Archaeopteryx resembles modern birds with the presences of primary and secondary feathers, a secondarily-evolved ornithischian hip condition, and an enlarged sternum.
- Above: an artist's depiction of Archaeopteryx.
Recent research is boldy proposing a new ancestor, which would replace Archaeopteryx. This organism is Xiaotingia zhengi, and the study's arguments exploit some valid evidence. If you get anything out of this post, I hope it is an understanding that the origin of birds is inevitably highly contentious until more of the fossil record is unveiled.
- Above: an artist's representation of Xiaotingia zhengi.
Subscribe to:
Comments (Atom)