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.
It's a mighty puny thread that can be highjacked with WORDS!
(We ALL know you have to have a metaphorical boxknife!)
"goat-headers"
What's a goat-header?
He doesn't have to create the Universe ~ just one new lifeform is sufficient, and it doesn't even have to be all that different ~
Silly!
This is EXACTLY how "Evolution" works!
A little 'change'...
A little 'mutation'....
BaddaBoom baddaBING....
and you gotchaself a NEW creation: old things are gone - all has become new.
Fascists with their fuhrer principle, and the Commies with Democratic Centrism, also believe in an objective reality which they can create and which everybody will believe even if they have to kill off the nonbelievers.
I think you should reassess your understanding of the place of "objective reality" in a universe where religious folks, of all stripes, accept change, revelations, miraculous occurrences, and so forth ~ all inexplicble at the time, but maybe explainable ultimately, and still useful in assisting in comprehending our existence for the time being.
Such mysticism allow them to accept the change that is constantly occurring.
Nonsense. Nobody is saying that an intelligent designer doesn't exist (man). That in NO way is evidence that Man is the intelligent designer of the universe. There is simply no evidence for a designer of the universe, or of life as we see it on Earth, that isn't easier explained with natural means.
"He doesn't have to create the Universe ~ just one new lifeform is sufficient, and it doesn't even have to be all that different ~"
Nope, that's poppycock.
For the same reason we snicker at flat earthers. The phrase "less than 100%" includes "99.999%".
An evolved goat-heRder!
(Or...
for those with dirty minds....)
Those aren't pics - they're drawings.
On the other hand, we do know there are bounds to species ~ they are not just our imagination.
You think goat-herders wrote the Bible?
However, the debate was not about the entire Universe, just ID as that applies to biological systems.
Not much difference between species in the cellular machinery.
Many times the phrase has been used by E's to try and denigrate the intelligence of the OT writers.
I thought the Hebrews were sheep herders who lived out on the plains. Goat herders live in the mountains ~ that would be the Medes.
Addendum: not ALL E's; just some of them.
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.