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Hey, it’s Random Scientist Inc. As you may or may not remember, I’m keeping you updated on the latest in dinosaur news; discoveries, breakthroughs, etc.
I recently read an article about Archaeopteryx. Apparently, paleontologists are starting to believe that it was less bird-like than previously thought. It has now been unofficially classified as a feathered dinosaur. Basically, it was bird on the outside and dinosaur on the inside.
New microscopic images of the ancient blood cells inside the bones of Archaeopteryx show surprisingly slow growth and maturation. In fact, scientists think it may have taken years to mature. In contrast, living birds grow rapidly.
The scientists also found that the rapid bone growth common among living birds but absent in Archaeopteryx wasn’t necessary for flight.
Fossilized remains of Archaeopteryx were first found in Germany in 1860, a year after Charles Darwin published “Origin of Species.” Its bird-like features, such as its feathers and its wishbone, and its reptile-like features, such as its teeth and its long, bony tail, made evolutionary theory more credible.
The bones of a juvenile Archaeopteryx were examined. The bones of the juvenile Archaeopteryx weren’t the fast-growing type. Instead, they found lizard-like bones.
Next they plugged bone growth rates into the size of the thigh bones of the Archaeopteryx to predict the rate of growth. What they learned was the adult Archaeopteryx would’ve been about raven-sized and would’ve taken about three years to fully mature. This resembles dinosaur growth rates. This proves that birds were able to fly with dinosaur physiology.
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Archaeopteryx is not a dinosaur. It is an archosaur. The similarities of dinosaurs and Archaeopteryx has more to do with convergent evolution. Birds evolved from a closely related common ancestor most likely during the middle Triassic adaptive radiation of archosaurs. For example the three fingered had of Archaeopteryx representing digits 2,3,4 has been molded by natural selection for climbing trees grasping prey to look remarkable similar to the tree finger had of dinosaurs which are digits 1,2,3. The digit homologies are a major problem for the birds are dinosaur theory. What about tooth morphology? Larry Martin from University of Kansas has pointed out that the teeth of Archaeopteryx are more similar to crocodiles than they are to theropod dinosaurs.
I didn’t say I agreed with the article, I was just writing a summary of it. I know Archaeopteryx is an archosaur.
well, all dinosaurs are archosaurs - including the ones that fly ;) Needless to say I disagree strongly with Al Nolfi here.
Guys like Larry Martin are strangely stubborn when it comes to the ancestry of birds. They’ll say "Okay okay, we admit that maniraptorian dinosaurs were bipedal, lightly build, laid eggs in nests, brooded, slept with their head tucked under their wing, had pennaceous feathers and down, quill knobs on their forearms, a wish bone, a backwards pointing pubic bone, an enlarged sternum, proportionally long arms, three fingered hands, long index fingers, hollow bones, air sacks that lighten their skeletons, and that they are present all the way back in the Jurassic period alongside Archaeopteryx, all of which would make them prime candidates as the ancestors of birds. BUT, we have this one little, pesky detail in the way we interpret wing digits that makes us REJECT all the above evidence as convergent evolution. Therefore; birds are not dinosaurs!"
The thing is; wing digits in birds are numbered 2,3,4 because the wing of a developing bird embryo has a little cartilage lump next to digit 2 that biologists have always interpreted as a reduced digit 1. These biologist might be wrong, perhaps bird digits are in fact 1,2,3 - just like in theropods. I find that much to be a much more reasonable hypothesis than rejecting the long list of similarities ;)
Also; research from 2005 shows that the pattern of gene expression in digit "2" of a bird embryo is identical to the digit 1 expression patern in both mice and aligators.
http://www.ncbi.nlm.nih.gov/pubmed/15515040
It seems to me that you are really "locked into" a belief system–which is evident from your reply to my inquiry. It seems that the less someone knows, the more rigid they act in the face of any data or option to the contrary.
"the less someone knows, the more rigid they act"
Hmm.. nope. Take for instance; ornithologist Alan Feduccia, who agrees with Larry Martin and have written articles with him on this subject. Feduccia is a brilliant ornithologist, author of important work regarding extinct birds. He used to have an impressive list of reasons why birds could not be dinosaurs; dinosaurs are massive while birds are small, Archaeopteryx is too old to be descendet from cretaceous maniraptors, no dinosaurs have ever been shown to have feathers, bird lungs are unique, digits 1,2,3 versus 2,3,4 and so on.
That list has now grown very short, but Feduccia rigidly insists that birds are not dinosaurs.
One thing makes me currious: Why do you write that Archaeopteryx had digits 2,3,4?