Posted on 04/02/2004 4:25:18 PM PST by PatrickHenry
Arlington, Va.—How land-living animals evolved from fish has long been a scientific puzzle. A key missing piece has been knowledge of how the fins of fish transformed into the arms and legs of our ancestors. In this week's issue of the journal Science, paleontologists Neil Shubin and Michael Coates from the University of Chicago and Ted Daeschler from the Academy of Natural Sciences in Philadelphia, describe a remarkable fossil that bridges the gap between fish and amphibian and provides a glimpse of the structure and function changes from fin to limb.
The fossil, a 365-million-year-old arm bone, or humerus, shares features with primitive fish fins but also has characteristics of a true limb bone. Discovered near a highway roadside in north-central Penn., the bone is the earliest of its kind from any limbed animal.
"It has long been understood that the first four-legged creatures on land arose from the lobed-finned fishes in the Devonian Period," said Rich Lane, director of the National Science Foundation's (NSF) geology and paleontology program. "Through this work, we've learned that fish developed the ability to prop their bodies through modification of their fins, leading to the emergence of tetrapod limbs."
NSF, the independent federal agency that supports fundamental research and education across all fields of science and engineering, funded the research.
The bone's structure reveals an animal that had powerful forelimbs, with extensive areas for the attachment of muscles at the shoulder. "The size and extent of these muscles means that the humerus played a significant role in the support and movement of the animal," reported Shubin. "These muscles would have been important in propping the body up and pushing it off of the ground."
Interestingly, modern-day fish have smaller versions of the muscles. According to Coates, "When this humerus is compared to those of closely-related fish, it becomes clear that the ability to prop the body is more ancient than we previously thought. This means that many of the features we thought evolved to allow for life on land originally evolved in fish living in aquatic ecosystems."
The layered rock along the Clinton County, Penn., roadside were deposited by ancient stream systems that flowed during the Devonian Period, about 365 million years ago. Enclosed in the rocks is fossil evidence of an ecosystem teeming with plant and animal life. "We found a number of interesting fossils at the site," reported Daeschler, who uncovered the fossil in 1993. "But the significance of this specimen went unnoticed for several years because only a small portion of the bone was exposed and most of it lay encased in a brick-sized piece of red sandstone."
Not until three years ago, when Fred Mullison, the fossil preparator at the Academy of Natural Sciences, excavated the bone from the rock, did the importance of the new specimen become evident.
The work was also funded by a grant from the National Geographic Society.
Next from the Univ of Chicago and the Academy of Natural Sciences:
Global Warming To Turn Earth Into A Charcoal Briquete
Homosexuals Born That Way And Can't Change
Capitalism Bad
The fish were, and their fossils record the facts.
Criminals: It's SOCIETY'S Fault
It's pigs and sheep
The Sophists at the top of the Creationist food chain are quite good at formulating slogans simple enough for the minions to remember and bleat.
No that isn't all!, but nice try!!, and why are you shouting??????
The religion of the Evol-Doers can sure make a lot of theology from very little
Evolution is neither a religion nor theology. Are you sure you understand the topic you're attempting to discuss?
(And could someone explain to me why the nastiest insult anti-evolutionists can think of to throw at evolution is to call it religion? Hmm...)
- and nebulous - evidence.
The evidence for evolution is hardly nebulous, it's vast and overwhelming. Go do some homework sometime.
Talk about the miracle of loaves and fishes.
Wrong topic.
What a crock of cr@p
What a straw man fallacy.
Some of them really believe there's never going to be another gap filled. The experience of the last 145 years means nothing to them.
Next from the Univ of Chicago and the Academy of Natural Sciences:
Global Warming To Turn Earth Into A Charcoal Briquete
Homosexuals Born That Way And Can't Change
Is this your way of revealing that you can't refute the finding on its merits?
None of the vast evidence for evolution has ever caused me to doubt God the Creator. God created us; evolution is how he did it.
I almost put my faith in the fairy tale of junk science! Whats the latest imperical fairy tale ?
...he said, typing away on a computer.
Oh yeah, I heard it the other day " all of a sudden an explosion of life rapidly evolved as a result of increased oxygen in the atmosphere. Billions of DNA molecules with infinitely complex codes, appeared at random and aranged themselves into brains, eyes, ears, lungs and gills, etc all at once."
Do you know that the theory of evolution teaches nothing like that?
I heard about a guy who, as he was being strapped into the electric chair, cried out: "One fingerprint! That's it? That's all they had to link me to the crime scene! What a crock!"
Like, how many does it take?
Victory? What victory? Fish and amphibians are genetically linked. It's nice to see the predicted pieces of the puzzle falling into place. But if this fossil isn't any good, another will turn up eventually.
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