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Newly found species fills evolutionary gap between fish and land animals
EurekAlert (AAAS) ^ | 05 April 2006 | Staff

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.


TOPICS: Heated Discussion
KEYWORDS: 375millionyears; coelacanth; crevolist; lungfish; tiktaalik; transitional
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To: VadeRetro

Oh, and another thing....God does not make mistakes.


241 posted on 04/05/2006 1:40:59 PM PDT by yellowdoghunter (I sometimes only vote for Republicans because they are not Democrats....by Dr. Thomas Sowell)
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To: yellowdoghunter

"I must say that I hope scientists continue to talk down to people, assume they are stupid, etc...it only bolsters the argument that scientists think they are smarter than God."

People who live in glass houses shouldn't throw stones.


242 posted on 04/05/2006 1:41:04 PM PDT by CarolinaGuitarman ("Things are not what they always seem.")
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To: js1138

Ummm, is that sarcasm?


243 posted on 04/05/2006 1:41:20 PM PDT by Zavien Doombringer (The UN 1967 Outer Space Treaty is bad for America and bad for humanity - DUMP IT!)
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To: CarolinaGuitarman

I use velcro tipped nref darts...


244 posted on 04/05/2006 1:42:11 PM PDT by Zavien Doombringer (The UN 1967 Outer Space Treaty is bad for America and bad for humanity - DUMP IT!)
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To: yellowdoghunter
There is that word again [theory]. Evolution is just someone's idea, not a fact.

By your logic Music Theory means that music is "just someone's idea" and it must not exist.

245 posted on 04/05/2006 1:42:14 PM PDT by Condorman (Prefer infinitely the company of those seeking the truth to those who believe they have found it.)
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To: Zavien Doombringer
Ummm, is that sarcasm?

Nooooo!

246 posted on 04/05/2006 1:42:45 PM PDT by SlowBoat407 (The best stuff happens just before the thread snaps.)
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To: VadeRetro

Normally I find animals that look like they are in-between major phyla somewhat icky & threatening. But those mudskippers are sooooooooo cuuuuuuuute!!!


247 posted on 04/05/2006 1:42:51 PM PDT by jennyp (WHAT I'M READING NOW: Getting to Yes by Fisher & Ury)
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To: Ichneumon

no it doesn't, that the evidence of God's Global Flood invalidates any of mankinds means of rationalizing it away.


248 posted on 04/05/2006 1:43:24 PM PDT by Zavien Doombringer (The UN 1967 Outer Space Treaty is bad for America and bad for humanity - DUMP IT!)
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To: CarolinaGuitarman
People who live in glass houses shouldn't throw stones.

You are right, they shouldn't. It is a fact that the glass will break...:)

249 posted on 04/05/2006 1:43:24 PM PDT by yellowdoghunter (I sometimes only vote for Republicans because they are not Democrats....by Dr. Thomas Sowell)
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To: All
But it's "JUST a THEORY" . A few of you really ought to read this.
250 posted on 04/05/2006 1:43:47 PM PDT by PatrickHenry (Yo momma's so fat she's got a Schwarzschild radius.)
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To: yellowdoghunter
" You are right, they shouldn't. It is a fact that the glass will break...:)"

Advice anti-science antievos should take to heart.
251 posted on 04/05/2006 1:44:34 PM PDT by CarolinaGuitarman ("Things are not what they always seem.")
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To: -YYZ-
That "speculation" is based on lots of evidence, both in the fossil record and through the study of extent creatures. The fossil tracks and the structure of the skeleton can tell us how the critter moved, and even how fast. Comparisons with modern animals can tell us how massive it was. Skin imprints (not uncommon for dinosaurs) give us a clue as to what it actually looked like. Fossilized remains of newborns tells us how independent the animal was after hatching; and the occasional remains of a parent with a nest provide clues as to the gestational habits of the critter. The teeth can tell us if it was a carnivore, herbivore or omnivore. The ratio of elements in the fossilized bones can tell us if it lived in fresh water or salt water (for waterborne animals), and give a clue as to its diet. Gastroliths found with fossilized remains also give clues as to diet. Fossilized nesting sites and the jumbled remains of drowned animals clue us into their social structure.

In other words, very little of the stuff you see scientists commenting on with regards to extinct fauna are pure speculation. Most of it is drawn from careful study of thousands of little clues.

252 posted on 04/05/2006 1:44:52 PM PDT by Junior (Identical fecal matter, alternate diurnal period)
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Comment #253 Removed by Moderator

To: CarolinaGuitarman
and cloning does what? gives rise to a like being made out of the same cells from a donor. Meaning that the clone is not an individual, yet a likeness of the host?

Then you cannot make a true clone, due to the fact that by age, clones are not alike either.

254 posted on 04/05/2006 1:46:21 PM PDT by Zavien Doombringer (The UN 1967 Outer Space Treaty is bad for America and bad for humanity - DUMP IT!)
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To: yellowdoghunter

Dude, I wrote that. I just filked the tune.


255 posted on 04/05/2006 1:46:33 PM PDT by Junior (Identical fecal matter, alternate diurnal period)
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To: Condorman
WOW! Now on to "MUSIC THEORY".....I avoided that class in college because I refused to waste my money on it, which is what I think it is, a bunch of bologna.

Of course, most of the people who I knew that took the class did so for an easy credit.

What more is there to really say about "Music THEORY"??? It is hogwash!

256 posted on 04/05/2006 1:46:44 PM PDT by yellowdoghunter (I sometimes only vote for Republicans because they are not Democrats....by Dr. Thomas Sowell)
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Comment #257 Removed by Moderator

To: yellowdoghunter
No, I was beautifully and wonderfully made in God's image. I hope that doesn't cause you to melt or anything...:)

Melt? Why should it? Even the Vatican admits that acknowledging the existence of evolution is not incompatible with religion.

Perhaps you have chosen to believe the creationist canard that all scientists are atheists or that the ToE is some atheist plot to undermine faith. Nothing could be farther from the truth.

If you are not a clone, you are living proof that species evolve.

258 posted on 04/05/2006 1:47:03 PM PDT by highball (Proud to announce the birth of little Highball, Junior - Feb. 7, 2006!)
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To: Junior

Well, I am still not going to go back and read it. Maybe that fits into the "Music THEORY"...:) LOL!


259 posted on 04/05/2006 1:48:46 PM PDT by yellowdoghunter (I sometimes only vote for Republicans because they are not Democrats....by Dr. Thomas Sowell)
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To: highball; yellowdoghunter
If you are not a clone, you are living proof that species evolve.

Yellowdoghunter thinks he is a clone.

260 posted on 04/05/2006 1:49:16 PM PDT by Lurking Libertarian (Non sub homine, sed sub Deo et lege)
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