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.
No, most people have observed it including yourself. Evolution is defined simply as occurring change or change is ongoing or a observed fact. The Theory of Evolution explains the observed fact. For the simplest proof there are 6.7 billion people on earth and no two have been found to be exactly the same so some change has occurred. Get a picture of your parents and stand in front of a mirror. If you are exactly the same no change has occurred and you are a clone. However is if there is any difference, no matter how small, some change or evolution has occurred. Evolution whether by reproduction or nature is still change.
Evolution is both a fact and a theory. What is a theory? The method of science is the observation or a material fact (evolution) evidence and empirical evidence of the fact (evolution), and a explanation of the fact that constitutes theory. A scientific theory is composed of facts and laws not someones opinion.
If by now you have looked in the mirror you may remain a clone in thought but that physical change has occurred is a material fact observed by your own senses.
Depends leakage.
"So you pop in to make vapid and laughably idiotic comments like, "They extrapolate so far from so little", and slap each other on the back about how "clever" you're being compared to those people you unjustly ridicule as "true believers", when instead you're just exposing your own ignorance, bigotries, and unfounded presumptions."
Hey, don't include me in that. My comments were limited to the popular dinosaur shows on TV, where IMO the scenes they re-enact, and the voice-overs, are wildly speculative about how dinosaurs actually lived and died. Good entertainment, bad science - hardly any better than "Jurassic Park" as science. For the record I believe that evolution is a fact and that the Theory of Natural Selection is a key mechansim in it.
However, I have no problem with people believing as they wish. On the other hand, you seem to have quite a problem with people who don't believe in evolution.
I guess we will all find out the answer sooner or later.
there you go again, musta hit a nerve, not so assured of your positions are you?
Wow, you're not real good on this "logical thinking" thing, are you?
Clue for the clueless: If I were not assured of my position, then someone questioning it wouldn't annoy me, because I'd be questioning it myself, thus I could hardly take issue with anyone else doing likewise.
Bigger clue for the clueless: The reason that snotty ignorance annoys me is precisely because I *am* very assured of my position, since it is based on over thirty years of personal research and validation and tens of thousands of pieces of evidence I have ensured fit the conclusions and validated it. Thus, when some know-nothing comes along and makes smirking claims that are entirely false, and prances around proclaiming himself the "smart" one while insulting everyone who *has* spent a lifetime actually educating himself on the topic, then *that's* when such childish behavior is likely to "hit a nerve", because it's just so overwhelmingly moronic and insulting, coming from someone who not only hasn't earned the privilege, but who is so clueless he doesn't even realize the depths of his own incompetence.
You're like Cindy Sheehan, who is annoying precisely *because* we're assured enough of our own position to recognize just what an airhead she is who just won't shut up -- despite not having a clue, she keeps on spewing more vicious nonsense, egged on by other know-nothings.
The many slight differences which appear in the offspring from the same parents, or which it may be presumed have thus arisen, from being observed in the individuals of the same species inhabiting the same confined locality, may be called individual differences. No one supposes that all the individuals of the same species are cast in the same actual mould. These individual differences are of the highest importance for us, for they are often inherited, as must be familiar to every one; and they thus afford materials for natural selection to act on and accumulate, in the same manner as man accumulates in any given direction individual differences in his domesticated productions.
http://www.columbia.edu/itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/Clarius_batrachus.html
Identification: Walking catfish, which are scale-less, are typically a uniform shade of gray or gray-brown with many small white spots along their sides. The head is flat and wide and the body tapers to the tail. The eyes are very small and the mouth is broad with fleshy lips and numerous small pointed teeth in large bands on both the upper and lower jaw. There are four pairs of barbels, one pair each of maxillary and nasal barbels and two pairs of mandibal barbels. The fish has a lengthy dorsal and anal fin that each terminate in a lobe near the caudal fin. The pectoral fins, one on each side, have rigid spine-like elements. To move outside of water, the fish uses these "spines" and flexes its body back and forth to "walk". The walking catfish is easy to distinguish from many of the other North American catfish because it doesn't have an adipose fin.
In addition to the brown or gray-brown coloring noted above, albinos and calico morphs are also possible. However, these are uncommon in the wild. For example, in Florida the fish that escaped were albinos but today the albino is rare and descendants have generally reverted to the dominant, dark coloring.
The fish reach reproductive maturity at one year and grow up to 24 inches in their native range. However, in Florida they rarely exceed 14 inches.
Walking catfish possess a large accessory breathing organ which enables them to breath atmospheric oxygen. They are well known for their ability to "walk" on land for long distances, especially during or after rainfall.
I remember these Walking Catfish from when I lived in So. Fla. They are still around.
I dunno, I didn't post it, ask the poster.
Excellent point.
Just your opinion, which you are welcome to. I however, disagree.
I still don't believe I came from a monkey!
I didn't post the picture in question, I am merely making a question. I see the upsidedown darwin walking fish as a creationalists attempt to show the dead theory of evolution. It wasn't my picture, nor do I subscribe to the point of view.
There's more waiving of arms and flailing about in this thread than there is in any spastic ward. It's the all-too predictable reaction to any new piece of evidence that ringingly confirms the theory of evolution (yet again).
"so we get: korean clone BS"
Remind me again who busted the korean cloner? Oh, that's right, other scientists who compete with the loser for fame and fortune!
Fakes are endemic all things where a buck is to be made --- witness the Shroud of Turin, pieces of the "True Cross," fake Chinese "antiques," and even Mozart's skull here lately.
Those fakes take away nothing from the fact of Christ, the beauty of Ming Dynasty Art, or the fact of Mozart's genuis.
And your source for this is?
There is that word again. Evolution is just someone's idea, not a fact.
Therefore, I do not see why people get all riled up about it, it means nothing. Believe me, people, there are many more questions than evolution will ever be able to answer.
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