Does bird;s knee running rule out reptile to bird evolution since the fixed hip is necessary for birds?see the research cited in
http://www.answersingenesis.org/articles/2009/06/13/news-to-note-06132009
Quick and Ruben's breakthrough was in recognizing that this "knee running" anatomy, where the upper leg bones are fixed, is crucial in keeping birds' lungs from collapsing. Thus, if birds walked like us, they would not be able to support the sophisticated pulmonary system that helps enable flight.
"This is fundamental to bird physiology," Quick explained. "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."
In the next phase of research, the scientists examined whether theropod dinosaurs' skeletons would have allowed a similar pulmonary system. But the evidence shows that skeletal differences—including a mobile femur—meant dinosaurs couldn't have given rise to birds. "Theropod dinosaurs had a moving femur and therefore could not have had a lung that worked like that in birds. Their abdominal air sac, if they had one, would have collapsed. That undercuts a critical piece of supporting evidence for the dinosaur-bird link," Ruben said.
Intriguingly, Ruben commented on the widely held dinosaur-to-bird-evolution model: "Frankly, there's a lot of museum politics involved in this, a lot of careers committed to a particular point of view even if new scientific evidence raises questions." A startling reminder—especially since it comes from an evolutionist—of how presuppositions play a role in determining science
- Archaeopteryx
Are you implying that bone structures cannot change and evolve?
- Suzi Q
Are you sure about that?
September 29, 2008
"A new predatory dinosaur with a birdlike breathing system found in Argentina may help scientists better understand the evolution of birds' lung systems....The fossil provides the first evidence of dinosaur air sacs, which pump air into the lungs and are used by modern-day birds, said Paul Sereno, the project's lead researcher and a National Geographic explorer-in-residence. (The National Geographic Society owns National Geographic News.)
Scientists have known dinosaurs used the pumplike apparatus to breathe, but the new find cements the connection between dinosaur and avian evolution, said Sereno, a paleontologist at the University of Chicago.
"This leaves little discussion that air sacs existed and that meat-eaters really do have lung structures that resemble birds," Sereno said."
http://news.nationalgeographic.com/news/2008/09/080929-new-dinosaur-missions.html
EDIT***
ooooh...look at this...hot off the presses.
"Beaked, Bird-like Dinosaur Tells Story Of Finger Evolution"
ScienceDaily (June 18, 2009) — Scientists have discovered a unique beaked, plant-eating dinosaur in China. The finding, they say, demonstrates that theropod, or bird-footed, dinosaurs were more ecologically diverse in the Jurassic period than previously thought, and offers important evidence about how the three-fingered hand of birds evolved from the hand of dinosaurs.
http://www.sciencedaily.com/releases/2009/06/090617171816.htm
- brucemoko
Since birds actually do have mobile femurs, it's hard to respond to this. see http://jeb.biologists.org/cgi/content/full/210/14/2548/FIG2 for an excellent diagram of an ostrich leg. Their basic leg design is quite similar to that of the hind legs of a horse or greyhound. also see http://www.bioone.org/doi/abs/10.1642/0004-8038(2007)124[789:TAOBFA]2.0.CO;2?cookieSet=1&journalCode=tauk
Also, thigh position in birds isn't critical to their lung function, and some dinosaurs apparently had a respiratory system similar to birds (e.g., see http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2596187).
I wouldn't call it "startling" so much as counterfactual. The central presupposition in science is that you're supposed to determine facts by observation and experiment, not by making them up.
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