Posted on 04/15/2005 6:39:50 AM PDT by doc30
Reproductive Riddle Unscrambled
A pair of fossilized eggs found inside pelvis of dinosaur supports a link with birds
Friday, April 15, 2005 Updated at 8:30 AM EST From Friday's Globe and Mail
Calgary — Scientists have for the first time discovered fossilized eggs inside the body of a dinosaur, which provides concrete clues about ancient reproduction and supports the theory that birds evolved from dinosaurs, according to research published today. The pair of hard-shelled eggs about the size of large, long yams were found inside the pelvis of a female oviraptorid, a meat-eating bipedal dinosaur that lived about 80 million years ago.
I was completely stunned," said the University of Calgary's Darla Zelenitsky, an expert in dinosaur reproductive biology, who was brought in to study the specimen found three years ago in China's southern Jiangxi province.
Never before have complete eggs been discovered inside a fossilized dinosaur, but there has been much speculation about whether dinosaurs laid numerous eggs at once like crocodiles or produced one egg at a time like birds.
A report published in today's issue of the journal Science finally puts an end to that debate.
"There's always been two camps among paleontologists: those that believe birds came from dinosaurs and those that believe birds came from other reptiles," Dr. Zelenitsky, the report's co-author, said. "But this provides further evidence that birds are from dinosaurs."
While crocodiles can lay 20 to 60 eggs at a time, it takes a modern-day chicken 25 to 30 hours to produce and lay one egg. That's because both oviducts, or Fallopian tubes, in reptiles produce many eggs at once, but in birds, only one oviduct is operating to produce one egg at a time.
"This specimen showed that these dinosaurs were more like birds in that they were laying one egg at a time," Dr. Zelenitsky said. ". . . but in this dinosaur, both the oviducts were functional like in crocodiles, but each oviduct was only producing one egg."
Previous discoveries of dinosaur nests of eggs or clutches have appeared as though the creatures laid their eggs in pairs but, until now, scientists had no proof that was the case. In fact, many denied the possibility that eggs were laid in pairs.
Renowned dinosaur hunter Philip Currie of the Royal Tyrrell Museum in Drumheller, Alta., pointed out that the only resolution to that dispute was the remote chance of discovering eggs inside a body cavity.
Uncovering this oviraptorid specimen, he said, is essentially like finding the "smoking gun."
Report co-author Tamaki Sato of the Canadian Museum of Nature in Ottawa said scientists finally have some answers about how dinosaurs laid eggs.
"This supports the bird-dinosaur relationship," she added.
The eggs studied are 18 centimetres long and six centimetres in diameter and are covered with ridges and bumps. While protected by a hard shell like bird eggs, rather than a leathery one as in reptiles, these eggs are neither bird-like nor crocodile-like in appearance.
Oviraptorids were toothless, short-beaked creatures that weighed about 40 kilograms and were about two metres long. They were also initially thought to be the egg-stealers of the Upper Cretaceous period.
evo ping please?
COOL! Good post
At long last the Chicken vs. Egg conundrum solved!
Of course, The Institute of Creation Science hasn't weighed in on this yet....
I'm still waiting for thier answer as to why the dinosaurs perished in the Flood, but not the birds or reptiles. I guess dinosaurs must have been sinful and deserved destruction.
I didn't think there were any scientist left who didn't accept that modern birds are nothing but legacy dinosaurs.
This birds evolved from dinosaurs debate is taken too seriously. It is just dividing the scientific community into two camps that feel they need to fight against each other about it.
Obviously birds evolved from earlier species. Whether it was the dinosaurs line or the reptiles line or amphibians is not important enough to fight about endlessly.
It would be better to just find the specific species that eventually led to birds.
Some years ago there was talk in the state of Maryland of selecting a state dinosaur, despite the fact they already had one: the Baltimore oriole.
This explains where birds come from, but now we must ask....WHERE do alligators, lizards, snakes and other REPTILES come from? It would seem to me that this proves that dinosaurs were not reptiles but really GIANT FLIGHTLESS BIRDS, and warm-blooded to boot.......
Evolve your thinking -- here's one:
Dr. McIntosh is Reader in Combustion Theory, Department of Fuel and Energy, University of Leeds in the United Kingdom. He holds a B.S. with first class honors in applied mathematics from the University of Wales, a Ph.D. in the theory of combustion from the Cranfield Institute of Technology, and a D.Sc. in mathematics from the University of Wales. He has contributed chapters to 10 textbooks dealing with combustion theory and published over 80 research papers. Dr. McIntosh is the author of Genesis for Today: Showing the Relevance of the Creation/Evolution Debate to Today’s Society.1And here's part of what he says:
Flight cannot be explained by supposed evolutionary change. The attempts to find any transitional forms have all failed. Archaeopteryx has been shown to have fully developed flight feathers (thus, no half-bird), with other recognizable birds found fossilized at a lower level. Other supposed “pro-avis” creatures (half reptile/half bird) have never been found. The evidence is overwhelming that birds have always been birds, and is entirely consistent with their being created right at the beginning on Day 5, just as the Bible says.It is not scientific to argue, on the one hand, for the obvious design of a Boeing 747, and then rule design “out of court” when considering the far more versatile flight of an eagle, falcon or the remarkable hummingbird. Modern minds within the secular media are presenting an unscientific duality of thought when praising engineering complexity in man-made machines, glorying in the great creative advances of mankind, but presenting the complexity in the world around us (of often far greater intricacy than man-made machines) as due to a gigantic unplanned cosmic experiment, with no Creator.
Dr. McIntosh is Reader in Combustion Theory, Department of Fuel and Energy, University of Leeds in the United Kingdom. He holds a B.S. with first class honors in applied mathematics from the University of Wales, a Ph.D. in the theory of combustion from the Cranfield Institute of Technology, and a D.Sc. in mathematics from the University of Wales. He has contributed chapters to 10 textbooks dealing with combustion theory and published over 80 research papers
Well he certainly seems the chap to go to to find out about the evolution of birds.
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Fossilized eggs, pong
Bold prediction (OK, it's already a postdiction): the people who make a science out of not getting things won't get this report.
Please help me on this one. Are they saying that a dino was laying bird eggs?
Add to that the feathered dinosaurs found in China. Looks like feathers evolved first as a means of controling body heat (i.e. keep the feather close to stay warm, puff them out and cool off). Modern bird feathers do this quite nicely and, this ventilator trick is something mammals can't do with hair very well.
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