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.
Sometimes, though, people don't really like to hear the truth.
The anti-evo crowd doesn't like to hear the truth and tries to ignore it and dismiss it. They can't convince 99+% of scientists so they misrepresent the TOE and try to convince the ignorant and gullible to back them in the political arena.
ID is not a scientific theory. I repeat, even Behe, a leading Discovery Institute and ID spokesman conceded under oath in a court of law that ID is not a scientific theory under the current definition of science, a definition that has been in place for hundreds of years.
One of my many failings. Mrs. Gumlegs maintains an exhaustive list.
You asked for ONE scientist who has more scientific education that[sic] we do, which I provided.
No, that’s not what I asked. Here’s what I asked (more than once): “”I’d like to see the name of just one who would accept your position, which I quoted before, " that if the pro-ID people got THEIR own dictionary, would that make it correct, or does this separate dictionary only apply for the evo THEORY?"
You do understand the distinction, do you not?
I asked a couple of tough, but valid questions, and rather than address them, you called them silly.
You’re not paying attention – I called them silly and addressed them. There’s a difference. I’ll post your questions and my answers again so you can see what I’m talking about. This time, I’ll omit the part with the characterization that seems to have blotted out the rest of the post:
Here's[sic] my criteria, using my own common sense as a free thinker:Here’s how I replied, (again, omitting the bits that threw you off):A) There is no proof that an ape can become a human.
B) Darwin convinced scientists to believe his theory based on antiquated information, at that time, like we only have one cell, when we really have trillions, and when there are new discoveries, evo scientists just change the theories.
The human body is made up trillions of cells.
Regarding B: “Darwin convinced scientists to believe his theory based on antiquated information.” I’m not sure what you mean by this, but Darwin’s theory was new when he proposed it. What “antiquated” information was he using? I don’t know where the “one cell” notion you’ve stated comes from but I’d like to see a citation – one from Darwin, and not Jack Chick. In any case, the Theory of Evolution doesn’t stand or fall on the number of cells in the human body – or any other body, for that matter.Your criteria have nothing whatever to do with science. How would “A,” for instance, address gravitational theory? Please note that the criteria I posted (again, I didn’t make them up), apply to every scientific theory. “There’s no proof that an ape can become human” is again merely an attempted attack on the Theory of Evolution, and is in no way support for any other theory. Incidentally, if it could be shown that an ape became a human, it would be considered disproof of the Theory of Evolution.
In my last post to you, I stated,
If, on the other hand, you start complaining about what you believe other theories do or don’t do, or pretend not to understand what “falsifiable” means in a scientific sense, then all you’ve done is demonstrate that you don’t know what you’re talking about.
All you’ve done is complain about the Theory of Evolution. You’ve just supplied an example of not knowing what you’re talking about.
Your objection to the Theory of Evolution being modified to account for new discoveries is more support for my contention that you don’t know anything about science. In fact, this objection is an objection not to the Theory of Evolution, but to science itself!
Get back to me when you can answer them.
Done. Before you posted your request for answers. But here they are again, anyway.
Thanks.
You’re welcome. Care to take a whack at answering the questions I’ve asked you?
But Darwin did not know that.
Why should Darwin be expected to know what your high school biology teacher would say circa 1965, or whether or not you remember it?
I'm astonished this line of argument is still going on. I would have thought the one cell wonder would have crawled under a roch to hide from shame.
Or at least some of his buds would have talked to him in private.
Even Penology mas moved on.
Good summation.
No mas penology.
I have it on the most unimpeachable of authorities (my Mum and Dad) that I was found under a gooseberry bush. Storkists and little-black-baggists are heretics. And that sex stuff sounds too yucky and squelchy. Teach the controversy!
Are we to blame for the appalling ignorance of your High School Biology teacher? You do understand that even in 1865 such a statement would have been considered laughable by anyone with a passing acquaintance with biology, don't you. On reading the thread I suspect that you don't.
Actually this is a problem for math. There are statements which we cannot say are true or not true.
"Actually this is a problem for math. There are statements which we cannot say are true or not true."
I should have qualified it to be some fields in math. There are of course unprovable theorems in math. My bad. :)
Evo dictates going across the species line (not creating subspecies).
So where's the proof that this can happen?
And please, no more games. It's a simple question, and it is the CORE of evolution.
Games only make ME look good, and you don't REALLY want to do that, do you? :)
Perhaps you can tell us what prevents continued change.
There was a time when only one man believed in evo - Darwin.
ID IS a scientific theory, and many scientists have said so (even IF it's true that Behe did not).
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