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.
I'll readily agree that what passes for "science" on the Discovery Channel is almost unadulterated speculation wrapped up in second-rate computer graphics.
Just wondering, what is the simplest life form that is able to be linked to the chain of evolution thus far?
Thanks
There are several scientists who would disagree with that.
The article only came out today in Nature. I know things are really fast on the web, but unfortunately most news sources seem to consider science rather boring.
This is just going to end up being another Archeoptrex (sp), where in 20 years they're just going to figure out it isn't a missing link....
Evolutionists want it boths ways. They want to claim missing links such as in a "Punctured Equilibrium" fashion, but admit that "Punctured Equilibrium" can't occur without:
A)Intelligent Design
B)Discounting everything we know about Micro-Biology
The fact is that the real problem Evolutionists have is that they have limited Origin Science (which is based on your philosophical pressupositions) to Material Monism without rationally proving Material Monism.
The fact is that Science holds to Material Monism without rationally proving it or even having the right to touch Origin Science. Origin studies reside in Philosophical worldview and Science shouldn't be messing with Philosophy.
Mudskippers are funny looking little dudes. Pretty amazing.
Thanks for the pic.
You really have no excuse to be so incredibly ignorant. Try reading a book sometime:
Mixing mom and pop's DNA produces a change by reproduction not a clone. The result is different from either. It is the simplest example of change (evolution).
The original motion filmed in a movie, however was not an illusion.
Or perhaps you think it was.
Anyway, you lose the argument because you have to resort to 3rd grade comments about someone's IQ. Good day!
What, exactly, do you believe that "theory" means when you say that "evolution is just a THEORY". Please be specific.
Why do people always ask this? Do you really think that it is a problem for the theory of evolution that bacteria/apes/fish/whatever still exist and that somehow all of the scientists just completely overlooked this problem and when you point it out we will all throw up our hands and say, "Oh no! How foolish we have been!"?
As the other poster pointed out, if America was settled by Englishmen, why are there still Englishmen today?? And once you are born, how can your parents possibly have any other children? They way some people speak about this you'd think people would be required to keel over dead after producing their first baby (which would soon make us extinct, alas).
Someone's idea. Many, many people may agree with that idea but it does not make it a fact.
Bravo!
I wouldn't want to go swimming in a Devonian ocean.
You have not yet answered, and I am still curious. Do you have actual statements of substance that you have not yet provided, or do you only have attacks of ridicule that do not even address the information being presented?
Just wondering, what is the simplest life form that is able to be linked to the chain of evolution thus far?
Thanks
Human evolution? I don't know. I'm not a scientist, strictly an interested amateur.
Perhaps one of the scientists here can answer that. The best I could do is a Google search, which you could well do yourself.
Judging from your posts, you sure as heck did!
Old ochre hound appears to be mired in the 3rd grade, probably as far as the old canine got.
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