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.
Anthropologists believe that the plural of anecdote is “data.”IOW--Anthropology is just sociology with relics. A social science trying to pass itself off as important.
Actually, anthropology has traditionally been divided into four primary fields: cultural, physical (biological/medical), linguistics, and archaeology.
The cultural and linguistics fields more closely resemble sociology, but the philosophical underpinnings are significantly different. There is limited use of the physical sciences, and some use of statistics.
The archaeology and physical anthropology fields (in which my primary training is) make extensive use of the physical sciences, so much so that they barely fit into the same department as the first two fields.
As an example, just in the past two weeks I have had to deal with faunal remains (animal bone and human bone), floral remains (pollen, phytoliths, and macrofloral), radiocarbon dating, stable isotopes (15N/14N, 13C/12C), lithics (the stone from which tools are made), and a number of other technical fields. Other fields we have to know something about include geology, soils, statistics (including sampling theory), etc. Occasionally the county coronor calls with interesting problems.
I am fairly accomplished in a couple of these fields, and have to be able to do all of the others at a basic level or better, and understand/interpret/compile the results supplied by other specialists for the studies I can't do myself.
And, unlike sociologists, archaeologists are not afraid to get their hands dirty!
Nice try at an insult, though; better luck next time.
Hook up a generator to your treadmill to get the POWER for your PC!
That's great! I imagine my accuracy will deminish while typing. Here, let me give it a try.
cab youuu telllleee whatrthI'm ewwrubthuhjfbjvahj./? djkshdhjdfgurfhgvyghoskj!hfjjj fucdj/'uryfsu_bd.
gprtghtoh whotrj so9ftheh sijrk
?! duhhhhhhhhhduhhdhhhjddrrrr.15$##%!#ye3876ubheyfytt!11.
How's that?
My advice is keep a clear head and a open mind. In my life time I have seen more change and knowledge than in the previous thousands of years. I can remember when some people thought cars a passing thing and a sin (some still do). Of the first TV in town some people called it the devils work (some still do). Going to the moon was thought impossible and many deny that we have done so today. The first impulse of most is to refuse new knowledge and attempt to show it false. By trying to show it wrong with all the various evidence they usually show it correct at the time. Things will continue to change at a increasing rate and as new evidence and facts occur the explanation may be different. That you question with a open mind rather then a effort to protect opinion is most favorable. A open mind has few limits. If a explanation changes, review the evidence that forced the change. Knowledge is not absolute and as new knowledge occurs some old knowledge will be refuted and thus one's views on matters will change. Thirty years from now if you only have today's knowledge you will be thought backwards whether we advance or decline. The answer is to continue to learn with a active mind. Try to learn something new every day.
The word 'theory'is being used in a scientific manner...its meaning within the scientific world, does not change depending on what people, whether pro-ID, pro-evolution, pro-creation, whatever...the meaning of 'theory' within the context of science does not change, depending on what people use the word...that is really just plain silly...otherwise everyone could go around making up whatever meanings they wanted for whatever words they wanted...and that makes no sense at all...
Pay particular interest to Descartes. Though not accepted he provoked much thought.
I have a question. What happens if science is forced to accept Creation or ID as a fact even if it is or is not? Who gets to explain the ID or God?
Sorry, I'm a free thinker. There are scientists that have more education than you or I, that agree with me, so what does continuing education have to do with it?
I'm also so secure in my beliefs that I don't need to put people down who don't disagree with me, as you and some other evos have attempted to do. Thou doth protest toooooo much.
ID is a scientific theory, and Evo is a scientific theory.
I don't know how evos can expect anyone to take them seriously when they are afraid to teach both theories in the classroom, and let students decide for themselves.
"....otherwise everyone could go around making up whatever meanings they wanted for whatever words they wanted...."
Kind of like what evo scientists do when they have a dictionary different from the rest of us????
ID is a scientific theory
Except that 99+% of scientists don't think it is, and that by the accepted definition of 'scientific theory' it's not. Saying it doesn't make it so.
Even Behe, under oath in a court of law in the Dover trial, admitted that the definition of science must be changed for ID to be considered a scientific theory.
So you can repeat this all you want, but it won't advance your cause at all. Better find a new slogan.
And I think there ought to be a limit on these crevo threads. Sideline them, combine them, put them in their own room, something. Fr is providing a venue for a gang of obsessive freaks who care nothing for conservatism.
The evo-freakboys got together and decided on a list of definitions for here on FR. Then they spam that list endlessly, like it's an authority. Just refuse to credit it, ask "why should I take your particular list seriously?" They'd love to believe they can set the terms.
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