Posted on 04/05/2006 10:32:31 AM PDT by PatrickHenry
Paleontologists have discovered fossils of a species that provides the missing evolutionary link between fish and the first animals that walked out of water onto land about 375 million years ago. The newly found species, Tiktaalik roseae, has a skull, a neck, ribs and parts of the limbs that are similar to four-legged animals known as tetrapods, as well as fish-like features such as a primitive jaw, fins and scales.
These fossils, found on Ellesmere Island in Arctic Canada, are the most compelling examples yet of an animal that was at the cusp of the fish-tetrapod transition. The new find is described in two related research articles highlighted on the cover of the April 6, 2006, issue of Nature.
"Tiktaalik blurs the boundary between fish and land-living animal both in terms of its anatomy and its way of life," said Neil Shubin, professor and chairman of organismal biology at the University of Chicago and co-leader of the project.
Tiktaalik was a predator with sharp teeth, a crocodile-like head and a flattened body. The well-preserved skeletal material from several specimens, ranging from 4 to 9 feet long, enabled the researchers to study the mosaic pattern of evolutionary change in different parts of the skeleton as fish evolved into land animals.
The high quality of the fossils also allowed the team to examine the joint surfaces on many of the fin bones, concluding that the shoulder, elbow and wrist joints were capable of supporting the body-like limbed animals.
"Human comprehension of the history of life on Earth is taking a major leap forward," said H. Richard Lane, director of sedimentary geology and paleobiology at the National Science Foundation. "These exciting discoveries are providing fossil 'Rosetta Stones' for a deeper understanding of this evolutionary milestone--fish to land-roaming tetrapods."
One of the most important aspects of this discovery is the illumination of the fin-to-limb transition. In a second paper in the journal, the scientists describe in depth how the pectoral fin of the fish serves as the origin of the tetrapod limb.
Embedded in the fin of Tiktaalik are bones that compare to the upper arm, forearm and primitive parts of the hand of land-living animals.
"Most of the major joints of the fin are functional in this fish," Shubin said. "The shoulder, elbow and even parts of the wrist are already there and working in ways similar to the earliest land-living animals."
At the time that Tiktaalik lived, what is now the Canadian Arctic region was part of a landmass that straddled the equator. It had a subtropical climate, much like the Amazon basin today. The species lived in the small streams of this delta system. According to Shubin, the ecological setting in which these animals evolved provided an environment conducive to the transition to life on land.
"We knew that the rocks on Ellesmere Island offered a glimpse into the right time period and the right ancient environments to provide the potential for finding fossils documenting this important evolutionary transition," said Ted Daeschler of the Academy of Natural Sciences in Philadelphia, a co-leader of the project. "Finding the fossils within this remote, rugged terrain, however, required a lot of time and effort."
The nature of the deposits where the fossils were found and the skeletal structure of Tiktaalik suggests the animal lived in shallow water and perhaps even out of the water for short periods.
"The skeleton of Tiktaalik indicates that it could support its body under the force of gravity whether in very shallow water or on land," said Farish Jenkins, professor of organismic and evolutionary biology at Harvard University and co-author of the papers. "This represents a critical early phase in the evolution of all limbed animals, including humans--albeit a very ancient step."
The new fossils were collected during four summers of exploration in Canada's Nunavut Territory, 600 miles from the North Pole, by paleontologists from the Academy of Natural Sciences in Philadelphia, the University of Chicago and Harvard University. Although the team has amassed a diverse assemblage of fossil fish, Shubin said, the discovery of these transitional fossils in 2004 was a vindication of their persistence.
The scientists asked the Nunavut people to propose a formal scientific name for the new species. The Elders Council of Nunavut, the Inuit Qaujimajatuqangit, suggested "Tiktaalik" (tic-TAH-lick)--the word in the Inuktikuk language for "a large, shallow water fish."
The scientists worked through the Department of Culture, Language, Elders and Youth in Nunavut to collaborate with the local Inuit communities. All fossils are the property of the people of Nunavut and will be returned to Canada after they are studied.
The team depended on the maps of the Geological Survey of Canada. The researchers received permits from the Department of Culture, Language, Elders and Youth of the Government of Nunavut, and logistical support in the form of helicopters and bush planes from Polar Continental Shelf Project of Natural Resources Canada. The National Science Foundation and the National Geographic Society, along with an anonymous donor, also helped fund the project.
They did?
I'm unaware of this.
If you are old enough to remember the differences of science and religious were of little concern until the late 70's. Since then with TV and the growth of fundamentalism science has been attacked. Many would discredit it in the schools and restrict knowledge. The number of students studying science has dropped and our world standing of high school performance in math and science has dropped from number one to 24 out of the top 25 countries in the world. We graduate but 70 thousand PH D's in math and science a year and more than half seek opportunity in other countries.
And you blame THIS on Creationism?
HMmmm...
I blame it on our fat, lazy, gimme attitudes instilled in our young, brought on by liberal politicians that almost to a man/woman are Evo's!
Virgin births are a dime a dozen these days. So, what about it?
____________
LOL. Who knew they did in vitro in those days.
And how many E's have?
What DIFFERENCE would it make to fill in the boxes in this poll anyway?
(You JUST wanna get 'em going, dontcha! ;^)
No thanks. I'll leave that to people who indulge sham philosophies as if they are science.
"(You JUST wanna get 'em going, dontcha! ;^)"
who me?? (smiling innocently)
But seriously the agenda on this issue is pretty blatant.
Here is my post:
CG: Nonsense. Nobody is saying that an intelligent designer doesn't exist (man). That in NO way is evidence that Man is the intelligent designer of the universe. There is simply no evidence for a designer of the universe, or of life as we see it on Earth, that isn't easier explained with natural means.
M: He doesn't have to create the Universe ~ just one new lifeform is sufficient, and it doesn't even have to be all that different ...
This appears to be Fester's oft-stated (and oft-denied) formulation that anything anywhere intelligently designed by anyone is evidence that everything everywhere was intelligently designed.
Fester tells me that's not what he means, but his posts can be somewhat murky. Mmuawiyah, on the other hand, seems to mean exactly that. Perhaps they can get together and sort it out for us.
To which, you responded:
That's simple logic.
Claim something less than universality and you're OK.
I certainly never claim universality on anything ~
All that's needed to knock down that argument is to find a single Intelligent Designer who has managed to create only one marginally different lifeform.
ADM qualifies as the Intelligent Designer.
They aren't the only one either, but they exist and do that stuff.
So, cranking that into your dichotomy forces us to believe that ID is correct, or that Occam is wrong.
No doubt you didn't anticipate Occam being at stake in the debate or you wouldn't have done that, but you really have to keep in mind that in an everchanging Universe, with recombinant DNA technology being used and under further development, we cannot fail to INCLUDE the existence of at least one ID in the pot.
He doesn't have to create the Universe ~ just one new lifeform is sufficient, and it doesn't even have to be all that different ~
I didn't interpret your comment that way, no problem.
I'm sure the sun will rise tomorrow, but you couldn't prove it by me, we don't see the sun enough. Ugh.
That's it? Any word if it will make the front page at least 28 times like Abu Ghraib (spelled right?) prison?
Welcome newb. I'm sure your stay will be short.
Who observed it? Obviously no one did, evolution is based on interpretation of available data. Depends on the interpreters agenda.
Obviously ~6.7 billion people observe it every day although you may be the exception. Evolution is defined as on going change Whether by nature or reproduction. Get a picture of your parents , stand in front of a mirror. If there are any differences no matter how small then some change or evolution has occurred. However if you can observe no differences and you are all exactly the same then you are a clone. Its up to you how you interpret the data. A few people still think they are clones but most agree that out 6.7 billion people no two are exactly the same.
Deductive reasoning without a fact of reality results in philosophy.
I don't remember even mentioning creationism or Christians in the post.
Please define philosophies and science.
Hey Coyoteman!
Thanks for the definitions.
My dictionary says that a theory means guesses.
So many dictionaries, so little time. :)
"My dictionary says that a theory means guesses. "
You need to get a real dictionary then.
Science cannot observe anything... Scientist's do the observing.
These same observations that can be obscured to speed processes, altered to fit a hypothesis and help push an agenda.
Science cannot do anything, it's those involved with science that do the work.
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