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.
Occuring change is evolution. You have just said of course evolution occurs.
Adaptation is occurring change and evolution. Change occurs by reproduction or nature. Adaption is by nature.
the species stays the same.
Which nomenclature? The nomenclature of species has been changed at least 4 times since Aristotle. A new species is defined as one so changed that it cannot breed with the original species as a Grey wolf and a sleeve Pekingese.
Affect faith and belief.
My A$$ is growing larger because I'm spending too much time on these threads and not enough on my treadmill. Is that evolution?
General it's a lack of knowledge of science and its method.There is a bias by some because they think it conflicts their faith and belief. Having a creationist, not of science, come into the lab and telling the scientist of his opinion of what should be method is akin to having the night janitor going into the operating room and telling a brain surgeon his opinion and what method he should use. Not that there is anything wrong with being a creationist, or janitor. They simply choose another path and education.
Faith is listed irrational because there is no argument for it that most would agree on. Belief can be rational if one can support it with logic. Yes, however most people make decisions based on their beliefs and many are incorrect.
I would agree with that.
As an aside to your post #1115, and your reference to Jim Jones...my aunt lived in northern California, in Redwood valley, just up the hill from the Jim Jones Church, that he had established in that little town...I was there visiting in the summer of 1977...my aunt never went to his church, but warned my whole family about his church...too many odd things had happened at that compound, which led many in that town, to suspect, that many things were so wrong with that church...my aunt, said going by there late at nite, every so often, one could catch a glimpse of what she called 'armed guards'...and there any number of really odd things going on there...not that is necessarily anything wrong with 'odd' things happening, but still it was an indication to my aunt that all was not as it should be for a church...this was her own opinion, of course, but borne out to be true in light of what happened not all that much later...
I have not been back to Redwood valley for a couple of years now..I think that at one time that church building had been turned into a community center...and Jones did build several buildings in the town center, which he controlled and operated as stores of some sort...today those buildings are still there now and are little stores, like a bakery, and other businesses, tho run by the local people of that town...
While I was down there during the 1989 and 1990, one of Jones followers who did not die in Guyana, set up a political office in Ukiah, 7 miles from the church...he was running for some sort of political office...people there still remembered him, and he lost the election...
Just thought you might like a little further info on Jim Jones...
Beer is good first aid.
I've heard that Guinness, Fosters, Corona, and in a pinch, Miller Lite work best.
I do realize that scientists have their very own dictionary.
Pretty convenient of them, huh?
I do realize that scientists have their very own dictionary.
Golf has it's own dictionary too. Fat means something completely different than what it does in everyday life. If you want to converse in (and criticize) the domain you need to learn the lingo.
What about the word 'love' in Tennis?...it means one thing in tennis, another thing applied to emotions...
Another great example. Better than mine.
As many times as the 'scientific' definition of theory has been posted, it never fails, that folks refuse to accept it, because it does not fit into their personal belief system...oh well...
As many times as the 'scientific' definition of theory has been posted, it never fails, that folks refuse to accept it, because it does not fit into their personal belief system...oh well...
I think it goes beyond that. The misleaders usually know they are misleading. There's a deliberate effort to sway people who are not informed by playing with words. And these same people claim to hold the moral and religious high ground. Ironic, isn't it.
I am not sure what the reason is...if its a deliberate attempt to mislead people, that is indeed, the moral low ground...if its an attempt to hide the meaning, because that meaning gives credibility, then the reason is one of fear...whatever the reason may be, its dishonest, in my opinion...
.if its a deliberate attempt to mislead people, that is indeed, the moral low ground.
I have to admit, I've reached the point where I assume this is the case. Perhaps I should step back more often and reconsider this. However, if I do and find that in every one of the first 20 cases I examine I find I was spot on, I'll quite wasting my time and resume assuming.
quite = quit
I will admit to you, there are certain posters, who I definitely, in my minds list, would include as those who are actually deliberately attempting to mislead people, and I do consider them to be of low moral character...some I am not sure of, so I give them the benefit of the doubt...and then every once in a while, someone comes along, who actually asks probing questions, appears to hold one opinion, but does take the time to examine the evidence, and then admits that perhaps they were mistaken in their original analysis, and come around to seeing things in a different light...but that is really quite rare...
I leave it to you, to guess which posters I put into my different categories...its all subjective, after all..
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.