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.
Of course, all of the 'true believers' hang on every word.
I was going to rebut this nonsense of yours, but I see that Right Wing Professor has already provided the perfect response a few posts earlier:
Here's a free clue. They are learned. They stayed in school, and read books and stuff. They learned biology from books and biologists, not preachers. They know stuff you don't. All you have is an opinion, and you know what opinions are like.Quite frankly, you guys who reflexively jump on these threads to gibber and snicker haven't the first clue about the *vast* amounts of evidence underlying these kinds of scientific conclusions. You presume that because *you* only know a few tiny scraps of information on these topics (and thanks to anti-evolution propaganda, much of the little you do "know" is wrong), that others are simiarly handicapped. Little do you know how little you know. And little do you know how enormous is the cross-validating evidence and repeatedly validated conclusions of evolutionary biology.
So you pop in to make vapid and laughably idiotic comments like, "They extrapolate so far from so little", and slap each other on the back about how "clever" you're being compared to those people you unjustly ridicule as "true believers", when instead you're just exposing your own ignorance, bigotries, and unfounded presumptions.
The constant snotty snickering from folks who haven't a clue what they're talking about gets old after about the ten thousandth time. Why don't you toodle off and actually learn something about the topic before you attempt to spout off again?
What is the bone/joint structure present on the pectoral fins of the fish you named?
This one had the beginnings of upper arm, forearm and wrist joints on it's pectoral fins. That's the significant difference.
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."
...he said, typing on his computer...
My dictionary says diatribe comes from a Latin word meaning learned discourse.
Take this website for example.
"he said, typing on his computer"
>>>>>>>>>>>>>>>>....................
oh there you go again.
Thanks for completely making something up yourself, then using it as a false accusation that *other* people might be likely to do that. It makes the dishonesty and emptiness of your response that much more obvious -- and pathetic.
what a scam these guys got almost as bad as astronomers who can "SEE" the very beginning of time..
...because they can, even though you're apparently too uneducated to grasp how that works.
what ego maniacs we have today in science..
You sound pretty damned arrogant yourself, son.
lets face it place it far enough back in time or far far away in the Universe and who can argue with them??
Not you, obviously, because you've come to the discussion entirely unequipped with anything beyond belligerence.
Post #141 applies to you too. Now run outside and play.
No amount of scientific jargon will change that.
To me, dumbass, clueless, twits are the ones that make elaborate, blotivating, authoritative statements and claims, on the flimsiest of evidence.
They are learned. They stayed in school, and read books and stuff.
Please don't make me laugh. Today's world is full of your type of 'learned' individual, ones with lots of facts and figures crammed into their heads by professors ( of which 99% of them could never make it in the real world). These kids graduate with virtually no ability to do any critical thinking whatsoever. If I had a nickel for every learned idiot who had very little common sense or ability to think on their feet, I'd have several million more dollars.
LOL! I could say the same about you. I, on the other hand, will consider all theories and beliefs and go from there. But I will not take evolution as a fact because it is not.
"Give a creationist a fish and he'll say you made it up."
Or point out the name of Allah on the side of the fish, either one.
I am not the one repeating the same mantra over and over.
The Theory of Evolution must really scare you. Shakes your beliefs to their very core.
Daniel Dennett likens it to a universal acid, and people like you prove his point magnificently.
Gravity is law I think.Actually gravity has laws and theories associated with it.
The theory of gravity explores the why behind the law. Newton and Einstein both had different ideas about why Gravity exists, and we still don't know exactly why two bodies attract each other, although general relativity has given us some great mathematical abstractions to begin our search for a true explanation.
In our search for the truth about Evolution, I think it can be said that there is a "law of evolution" and a "theory of evolution". That biological systems evolve is generally accepted to be true, and we may even find some laws there. Why they evolve, and if that evolution is a part of a greater plan, that is in the realm of belief and theory. The two things are orthogonal to each other, however sometimes a belief or theory gives rise to the discovery of a law.
I disagree.
I think a lot of students (not kids as you call them) graduate from University and College with good crtical reading and thinking skills compared to years gone by. A lot of them have facts and figures that are not from professors but from actual tested and observed facts that support the theories. A lot of them also understand the scientific theories involved in evolution.
One final point on your broad brushing of professors. The vast majority that I know can make it and have easily made it in the real world.
Great, here's your chance back up that statement.
Huge predators would have lurked in Tiktaalik's rivers and lakes,
Oh really?! Where is the ENORMOUS, CROSS-VALIDATED EVIDENSE for this drivel?
"Land had no predators,"
Really? Where is the ENORMOUS, CROSS-VALIDATED EVIDENSE for this drivel?
"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."
I think the missing link must have gills to be the missing link.
Meltdown. Aisle 158.
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