Enter the Dragon.

First of all, it has been nearly 2 months since I last posted a blog to this account and I apologize profusely for this. Lack of ambition and schoolwork has prevented me from being as focused as I usually am on making fun of scientists and their theories.

On with the show..

There has been great debate over the idea that birds are ancestors of dinosaurs. For this blog, I present the side that I support and hope becomes evident to you as you read on.


Feathers are scales!

Tetrapods, four-limbed vertebrates, are inherently webbed. This means that every fetus has webbed toes at some point, then a set of proteins allows the tissue between the toes to dissolve, thus making a non-webbed foot. There is an exception in this idea when it comes to ducks, where experiments have shown that some of this particular string of proteins to be absent. Zou and Niswander did an experiment where they injected both feathered and non-feathered subjects with a protein inhibitor to test this. The result was that the feet remained webbed and that the scutes, or thick scales, that normally cover a bird's foot turned into feathers. Crocodiles, a known ancestor of dinosaurs, also have scutes. The scutes of a crocodile are of a slightly different make-up than bird scutes, but still scutes nonetheless. If you can turn 'scutes' into feathers, the feathers on avian creatures we see today must have descended from scales with genetic differentials.

Systematics, my dear Watson!

Systematics is the age-old study of the evolutionary relationships between beings. The basic idea of this, long ago(hold fast to your roots, child) was that because something like a cow and a crocodile both had four legs, they must be related by a common ancestor. Thomas Huxley was contemplating a dinosaur bone once upon a time, during his dinner of quail. He was pondering over the fact that a bone he was currently studying was of a meat-eating dinosaur, the tibia. What he couldn't figure out is why this tibia was attached to a very strange other bone at the bottom. Thomas bit a piece of meat off of his quail drumstick and discovered, wah-lah!, that SAME BONE! It was later determined to be an ankle bone, but you get the idea.

22 is the magic number.

John Ostrom, as early as the 60's, determined that meat-eating dinosaurs and birds shared 22 characteristics that were not present anywhere else. Further study between now and then has lead us to 85 more discovered similar characteristics between the two. They must be related, right? It certainly makes it tough to decide. Ostrom is what is known as a "cladist" or someone who attempts to discern the origin of a species through its characteristics. Cladists believe that the origin and ancestry of a species can best be determined by the main characteristics that have stood the test of time.

Fly, little one, fly.

Arguers for the idea that birds are dinosaurs contend that the 'unnamed' dinosaurian ancestor of birds was once an arboreal, or tree dweller, or that birds learned flight from the ground by chasing and leaping after insects (there are plenty of little theropods, think T-rex but smaller, thought to have made a living by doing just that).

Archaeopteryx, the chosen one.

Both sides of the argument have agreed that Archaeopteryx, 145 million years old, was the first bird. It was discovered in Germany and had clearly defined feathers. It also had a very boney tail and teeth - hello, dinosaur. A-teryx also had a wishbone like birds of modern time. Many catty scientists would say that had A-teryx NOT been found with feathers they'd have labelled it a dinosaur. In fact, the five specimens discovered of it previously without feathers had been identified as the small dinosaur called Compsognathus.

B-list bird-dinos.

The 'Sinosauropteryx', ringing in at 130 million years old, was found in China. It is a dinosaur that was discovered surrounded in fuzz. Nobody really knows what the fuzz is, but it appears that they are early-versions of feathers. The fuzz itself consists of rod-like projections similar to what feathers do. A baby theropod, the only dinosaur ever found in Italy, called the Scipionyx has a well formed furcula, or wishbone. It wasn't the first furcula found in a theropod, but it is another piece of evidence in the meat-eating dinosaur-bird link. Reassessments of other theropods have revealed other bird-like features; hollow bones and a foot with three toes. These are bird-like features that appeared over 50 million years before the A-teryx ever got its pilot's license.

There are many more scientists, sources, and sites to help support the theory that birds are dinosaurs, as well as the opposing side. What I've presented to you are the main points that stand out to me.




Read more:

Dinosaurs and Birds: by Willis
Dinos NOT birds
Dinosauria
More links