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.
This has been discussed endlessly. I can't believe you ask me to post to you who have read it many times on other threads.
Michael Behe? Is he the only one you can think of?
I think some of these guys were overwhelmed to find it was just chemistry at work ~ they had been looking for something they called "the spark of life", and here was Darwin saying "it's in the screwing".
Later on we have Crick, et al, and DNA, and the discovery that it's not simply chemistry ~ it's an entire incredibly complex manufacturing, communications and data processing device at the root of it all.
If you could have shown DNA to Darwin I suggest he'd gone away confused and not sure if he should be an agnostic or engaged in serious prayer all the time.
It'd been too much for his Victorian mind (when they still thought everything was clockwork, and a "computer" was still someone who "computed").
Turns out there is no "spark of life", viruses exist and have genes ~ just plug them in to your own genome and maybe they'll do something ~ ? I think they can. Others still think that the only stuff you're ever going to get to work you got from your parents.
BTW, my statement is correct whether we are talking about "defined" or "hundreds".
That's not what is currently being claimed by those who seek to keep ID and Creationism out of the schools. They claim now that evolution is the very paradigm for biology itself, and you cannot understand the slightest thing about life without using evolution.
I doubt either position is correct, but there you have it.
Oh please. So long as you duck and weave it's unlikely that trans-species evolution will deal close questioning. With these tactics, the only way such theory of evolution will survive extinction is by government edict.
Gad.
No, scientists accept new models only through a process of attribiton where the old believers die off and are replaced with the new believers.
Yes, yes and yes. Have you ever worked with databases and tables as a programer?
Chaos doesn't really exist. Things just dump back into the vacuum.
Most of the New Testament consists of eyewitness accounts and moral arguments.
That's hardly an objective existence for the Bible.
It is not, as it were, a Koran, that is believed to be sacred in and of itself, and for which any abuse of same deserves the death penalty.
In short, the Bible is not an idol.
No, but you have to have sufficient evidence that doesn't admit of more than one interpretation. The fossil record should be be composed almost entirely of transitional forms. It isn't.
Every single bit of evidence you have requires a presupposition of trans-species evolution.
You have to know something for sure, and you don't.
"No, the Bible is merely a collection of pieces of papers. The stories in the Bible exist independently of the Bible's existence, either as a comprehensive library of books, or as the books themselves."
The Bible didn't exist until it was assembled and codified. It is taken as objective truth by Christians.
"Most of the New Testament consists of eyewitness accounts and moral arguments.
That's hardly an objective existence for the Bible."
I didn't say it WAS objectively true; I said that it is taken as objective truth by Christians.
"It is not, as it were, a Koran, that is believed to be sacred in and of itself, and for which any abuse of same deserves the death penalty.
In short, the Bible is not an idol."
So? That doesn't change the fact that what is written in the Bible is taken as objectively true by believing Christians.
Or that you are a space alien, and that Thetans fill my body. Sorry, you're babbling now.
One of the soundest arguments of philosophy (faith and belief) by Descartes for reason by doubt. That only you exist and that everything around you is created by your own thought for your own benefit. Solipsism is hard to refute by philosophical argument because one can deny anything. Science does not even address it because it has not been observed as fact. However the church denied and renounced Descartes's proof by argument. The soundest argument against Solipsism is that most who believe it are considered insane and reside in a insane asylum.
Like the introduction of a aimless random force that bring organization from disorder?
To the extent that you are suggesting that "natural selection" is a tautology, here is an interesting reply --
http://talkorigins.org/faqs/evolphil/tautology.html
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