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.
Hi!
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Lazy bozo's musta DROPPED their signs which read:
"No new long necks need apply."
tabular placemarker.
You may not have noticed it, but San Francisco is as far West, in terms of lines of longitude, as Guyana is East of Indianapolis.
This sort of relocation is typical of folks with a peculiar type of schizophrenia ~ the name of which I've forgotten at the moment.
The only way that concept becomes useful in discussion is if you are comparing metaphysical concepts with non-metaphysical concepts.
If you'd ever bothered to read any of my threads (rather than run off in a screamng rant) you'd noticed I use the terms "bounds" and "boundaries" ~ which are exceedingly useful in discussing speciation.
No, I haven't. It is you that doesn't have the capability for your own thought and are parroting the Evolution theory as fact. theory is not fact.
Gregorian chants are really cool, but Mozart had a different concept than Gregorian...
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Mozart's conception is much more highly evolved.
I would agree but the method of each are separate and different and are not interchangeable.
Time for some history lessons, but alas, I don't have enough time to re-edu-macate someone who could make that mistake.
I think this comes out of the public schools ~ the idea that history began with your last birthday.
I wasn't aware that religion as a whole believes in creation.
Interestingly enough, two of their prophets ~ little girls at the time ~ prophesied the coming of airplanes, automobiles, atombombs, tanks, cars, locomotives, etc. some time in the late 1700s.
That's why I was a bit startled to read: ".....More change has been forced on religion in the last 400 years than in all the years before that is of our history. Thoughts of cars, planes, going to the moon, TVs, radios, bathing suits and numerous other things would have made one a heretic and eligible for the death penalty..."
Visions of such things led neither to the destruction of the Church of the First Born, nor to their enlightenment.
We are the Cosmic Knowledge Fish, We are highly evolved beings...
Evolved to a more complex structure as he grew with a complex.
No support for borders at FR?! Who'da thought!
" I would agree but the method of each are separate and different and are not interchangeable."
Agreed.
They killed millions attempting to do so.
It really doesn't matter what you think they believed anyway ~ you're the guy who thinks science is not a subset of philosophy, and that mathematics is not also science.
With such a bizarre set of beliefs, I find it incredible you are able to get up in the morning and lie down in the evening.
You will never achieve satori in real time, nor the benefits of evolution you continue on in that state.
2000
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