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.
"so, mixing of DNA doesn't produce clones?"
No, it doesn't.
No thanks. I don't get my reading material from some rock band from way back when, I leave that for the Democrats.
The worldwide flood is a good place to start.
"That's because new, better information has been discovered. Do you think there should be NO speculation on these issues until there is 100% certainty?"
No. I understand that studying the bones of T.Rex allowed them to draw better conclusions about how it likely moved. But looking at bones and a few fossilized tracks can only tell you so much about how these critters lived - the popular dinosaur shows state as fact things that are almost purely speculation, giving fuel to the creationist's claims against the science.
so, then, you have a clone that doesn't have any DNA? Somewhere DNA has to be combined to create...You cannot get life with out life.
Like I said, we can agree to disagree. I must say that I hope scientists continue to talk down to people, assume they are stupid, etc...it only bolsters the argument that scientists think they are smarter than God.
I told y'all I was a passable amateur paleozoologist...
Actually, it's a fish.
http://www.wyattmuseum.com/noahs-ark.htm
These spastic twitches are the evidences of the fantastic new science of pig-ignorantism. If you don't understand the evidence, if you fill the threads with smokescreens, distractions, evasions, and denials, then there is nothing new and threatening to deal with at all.
That's not what he did. Try reading his posts again.
If that doesn't convince everyone, nothing will.
He shorted you in a few areas.
I read his post and responded. I believe he is able to answer for himself, though I am sure he appreciates your help.
Not wishful thinking, as some, before anyone can believe mankind evolved from any other creature, there has to be evidence of that, not creatures evolving to adapt to thier surroundings. Where is the proof of man evolving?
Unfortunately, that account violates a huge amount of the real-world evidence, and thus has been falsified.
If you ever managed to resolve all of those apparently insurmountable problems for the creationist version of a flood scenario, feel free to come back and present us with the results of your research. Make sure that your thesis is consistent with the totality of the evidence, however, and not just one tiny corner of it in isolation while violating most of the rest (a common creationist tactic).Problems with a Global FloodReview of John Woodmorappe's "Noah's Ark: A Feasibility Study"
The Geologic Column and its Implications for the Flood
Is the Devonian Chattanooga Shale Really a Volcanic Ash-Fall Deposit?
Geology in Error?: The Lewis Thrust
Thrust Faults and the Lewis Overthrust
What Would We Expect to Find if the World had Flooded?
Problems with Walter Brown's Hydroplate Theory
Burrows in the Orkney Islands contradict the Global Flood
The Fish is Served With a Delicate Creamy Mercury Sauce
The Letter The Creation Research Society Quarterly Didn't Want You to See
Microfossil Stratigraphy Presents Problems for the Flood
Why Would the Flood Sort Animals by Cell Type?
Isotopic Sorting and the Noah's Flood Model
Evidence from the Orkney Islands Against a Global Flood
While the Flood Rages, Termites Dig, Dinosaurs Dance and Cicadas Sing
More Nonsense on "TRUE.ORIGINS": Jonathan Sarfati's Support Of Flood Geology
Why Geology Shows Sedimentation to Be too Slow for a Global Flood
We will just have to agree to disagree.
Still waiting on someone to explain the complexity of the cell to me or "molecular machinery". Nothing in Darwin's "THEORY" accounts for the complexity of the cell.
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