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.
You left out a few steps. First there is the hypothesis and then there must be observation of a material fact, evidence and empirical evidence for the fact and a explanation of the fact that constitutes theory. Theories are composed of facts and explanations of facts not a accepted hypothesis of what if.
I made no comment whatsoever on your IQ or intelligence.
Being ignorant simply means you lack knowledge.
But you seem to be perfectly happy with that. Have a nice life.
Didn't you mother teach you that you instantly lose the argument when you do that? You should have also learned that in debate class. You instantly lost the argument.
Anyway, have a good day!
I figure we will all find out in the end anyway. I don't think I came from a monkey because I believe God created man in His image. You may believe differently. It is a belief that everyone is entitled to.
Dimensio: What, exactly, do you believe that "theory" means when you say that "evolution is just a THEORY". Please be specific.
yellowdoghunter: Someone's idea. Many, many people may agree with that idea but it does not make it a fact.
Wow. That is so stunningly ignorant, I hardly know where to begin.
How about we begin with the second point? You're right about one thing. The number of people who chose to believe something is not relevant. Thank you. Now maybe creationists will stop pointing to polls as some sort of evidence. What is relevant is who supports it, and why. No reputable scientific organization has any serious doubt about the validlity of the ToE. Not even ID groups such as the poorly-named Discovery Center, which accepts the evidence of a common ancestor.
Now, as to your first point. Words mean things. In science, the word "theory" means a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena.
It does not mean "guess." Far from it. It requires actual evidence, which the ToE has in spades. It has been tested, and every test strengthens it.
Hint: if you have to re-define words to make your argument, your argument is weak. That's a leftist trick that Creationists have eagerly adopted.
I just made the observation that your experience base does not appear to go beyond the 3rd grade.
I don't think I came from a monkey because I believe God created man in His image. You may believe differently. It is a belief that everyone is entitled to.
Of course everyone is entitled to believe what they like. But don't pretend your personal preference is anything but just that - a personal preference.
You have been asked for evidence to support your assertions about scientific matters. To which you can only reply that they are your beliefs.
I take it that you have no actual evidence?
Are gastroliths the stones swallowed by dinosaurs to aid with digestion?
And how do you know that this passage is evidence of God making a mistake?
Does man not have free will to commit acts that are then punishable?
You are right, they shouldn't. It is a fact that the glass will break...:)"
Are you sure thats a fact?
Unbreakable Glass
Reported September 2005
MURRAY HILL, N.J. (Ivanhoe Broadcast News) -- It's an unlikely discovery at the bottom of the sea that could strengthen our future; unbreakable glass.
Glass is fragile, but something found in the sea may change that. It has survived here for billions of years and is made of glass. Joanna Aizenberg, Ph.D., physical and material chemist at Bell Labs and Lucent Technologies in Murray Hill, N.J., says, "It uses every structural feature we know in mechanical engineering, but at a scale that is 1,000, 10,000-times smaller."
In fact, it's one of the strongest glasses known to man. Aizenberg is studying how the sponge is formed and has discovered individual needle-like glass beams make up the basic structure. "Each of the strands is about the thickness of a human hair. Actually half of a human hair," she says.
Today, architects use fiber-reinforced cements, bundled beams, and diagonal beams to reinforce building columns. You can see it in the Eiffel Tower in Paris and the Swiss Re Tower in London. Engineers hope to use what they've learned about the formation of the sponge's glass beams to help create better, stronger and cheaper materials for the future.
Elsa Reichmanis, Ph.D., director of Polymer and Organic Materials Research at the Bell Labs and Lucent Technologies in Murray Hill, N.J. says, "As scientific research is evolving, we are now starting to explore and understand more of what nature does every day very easily."
The sponge cannot only show scientists how to produce glass at low temperatures, but the sponge also has optical fibers that glow in the dark.
Great way to start off an argument. I won't even waste my time. A theory is just a theory no matter which word you wish to put in front of it.
Good Day.
She must have majored in "How to Act Like a Baby".
Biology and Music were too beneath her.
Notice that word, "COULD". Doesn't sound 100% for sure to me, maybe you read it differently. And if so, to each his/her own.
It has been fun, gotta run.....
When it comes to hard core trolls, the answer is don't.
Ping to self for later reading.
Mudskippers are actually real big gobies.
I don't follow any of this.
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