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.
If you were the Pope, we could have a discussion where we at least understand the words in the same way, and we might arrive at some new understandings.
Unfortunately, you are not the Pope, I am not a Catholic, and we seem to share a totally different understanding of the terms required to effectuate discussion.
Wikipedia is not a reliable, trustworthy source. That's because anybody can go in there and write anything they want. I've done it myself.
ADMDidit placemark
They are just trying to protect the REST of us from...
Muslims (Mohammed was God's LAST Prophet: PBUH)
Mormons (Brigham is His Prophet)
JWs (Prophet? Who needs a prophet when you've got a FINE organization like the Watchtower?)
Scientologists (Yo momma HOLLERED too loud when you wuz born! We gonna deprogram you! Give us money!)
Nope.
At least they have made some kind of decision.
I have made a decision. I've decided that the evidence is such that there is no way to make any informed, objective conclusion about the matter absent additional evidence, and that most people who have reached a conclusion have done so out of emotion, not reason. (Which is fine; emotional decisions aren't per se bad, just not how I think the issue should be approached.)
Individuals differ from their parents, but this, by itself, is not evolution.
Evolution is change in the frequency of alleles in a population. Individuals cannot be so different from other members of their species that they cannot breed.
Evolution by sudden change is a Hollywood fiction. It is sad to see conservatives so caught up in Hollywood that they cannot understand science.
He proposed it long before that event.
Working scientists (with all their degrees and so forth) were undoubtedly in their late 20s and early 30s at the youngest when they first read WEggener's thesis. 40 years later they were like some of the elder denezens of Free Republic ~ still writing, but trapped in their crystalized memories, unable to adjust to the new world.
This, Master, I have kept since childhood!
I agree with you regarding the application of occam's razor. Nature seems to be a mechanism of design. If that is so, science would only be discovering the way in which that mechanism works.
Then there are a couple of "fronts" ~ one in Utah, and the other in the Himalayas, that may well have changed elevation by up to 15,000 feet in ONE DAY.
Then there are the "hot spots" around the world, and the volcanos popped up over subduction zones.
Fast and hot ~ hardly "gradual".
A "mutation" might start in the tissues that create sperm and eggs, and the "owner" might well never exhibit the mutation, yet all of the offspring would.
Demonstrating that humans CAN'T genetically modify or even create life pretty well shows evidence of an entity or entities doing it 4.6 billion years ago!
Provide the facts or such studies by science.
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.
Id and Creationism will be explained by science when they are observed as a material fact. Until then they remain the argument of faith and belief.
I doubt either position is correct, but there you have it.
Doubt is the method of solipsism
Do you have objective evidence that Hinduism is in error?
UHhhh...
Because Evolutionist state so assuredly that it all started out so SIMPLE??
vs.
For all practical purposes they were dead since tectonics didn't come along until 40 years after his work was first translated into English. He proposed it long before that event. Working scientists (with all their degrees and so forth) were undoubtedly in their late 20s and early 30s at the youngest when they first read WEggener's thesis. 40 years later they were like some of the elder denezens of Free Republic ~ still writing, but trapped in their crystalized memories, unable to adjust to the new world.
ah, so now you move from a doubled-absolute statement-as-fact into equivocation and pure speculation. very nice. good day.
I'm sure there's a connection lurking in this.
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