Newly found species fills evolutionary gap between fish and land animals

EurekAlert (AAAS) ^ | 05 April 2006 | Staff

[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.

[jec41]

Ah, so, of course, you 99% of the scientists would be willing to stipulate to an intelligent designer as well as anything, as the genisis of life on Earth, then.

Just as soon as you observe ID as a material fact and have evidence of the fact science will attempt a explanation. No fact no explanation!!

[metmom]

Evolution is both a fact and a theory.

BTW, neither facts OR theories are ever proven 100%.

So which is it? If a *fact* cannot ever be proven 100% then how do you know that it's a fact? And if nothing is ever *proven* 100%, then why all the insults and derision towards those who are skeptical and don't accept it 100%?

[jec41]

Ok, not that I really ever like getting into to this, but evolution is ABSOLUTELY NOT AN OBSERVED FACT.

Evolution is defined as ongoing change no matter how large or small or whether by nature or reproduction. Look in a mirror, if you are exactly like your parents and there is not the slightest different then you are a clone. However if there is the slightest difference no matter how small some change (evolution) has occurred. A theory cannot exist without a observed material fact supported by evidence and empirical evidence. It is the definition of the scientific method.

[William Terrell]

I do not understand. There exists no such theory.

Why, of course there is. The doctrine is found in all the writings and speeches of the major evolutionists for many years. It is and has been plainly stated by those who write in the field and those who teach it. The implication is a plain as arc light.

The debate exists because certain individuals find certain observations of reality a challenge to religious beliefs that they do not wish to abandon.

Why do you care? Because they attack evolution? Evolution is attacking them. Maybe that's why they care.

[metmom]

OK thanks.

[WKB]

So which is it?



Which ever one they need at the time.
Just like the Clintons.

[William Terrell]

Should evidence of such a designer be found, I do not see why not.

I agree. Should such evidence of men creating self-sustaining life from basic elements and imbuing it with programed animation with survival and reproductive behaviors, and show how it could have started on its own, I don't see why not either.

[William Terrell]

Pure chance organizing basic elements into the vast interactive systems evident now, plant, animal and insect? Occam's butter knife.

[Central Scrutiniser]

If this is such an earth shattering story, why doesn't God just break into the evening news, and say "evolution is not real, the earth is 5000 years old, fossils are just bollocks, etc?"

I have to guess that the lack of Him doing that would mean that He doesn't have a big problem with Evolution.

[Conservative Texan Mom]

This is a common misconception.
Faith falls under a category known as epistemology mistakes. Epistemology mistakes lead to "irrational epistemology", which supposedly leads to impaired functioning of the mind.
Arguments for God fall under mystical metaphysics. Many ideas regarding any form of Deity have no basis in reality. Greek myths are a good example of this. The FSM would be as well. Text book explanations of philosophy would also include God. I do wonder how historical records of Jesus's existence and early Christianity would affect this though, as there can be made a logical argument for his existence at least.

I am a Christian, so I suppose some would say that I am guilty of having an irrational epistemology. I do not believe so, but then again, I'm not convinced the text book reasoning is completely correct. However, it could also be that I'm choosing to believe in spite of rationale. I do find it interesting that many of the values that we hold to be moral solely on philosophical reasoning are also consistent with Christian values. As for the Ten Commandments, the first three deal with showing reverence for God, the other seven are also in line with values that philosophy has determined to be beneficial to life and happiness. Philosophy of Religion is different from philosophy in general. It is reasoned, though, that religion gave birth to philosophy which gave birth to science. Science was originally philosophy of nature. They are all linked, but have become separate. Sometimes I'm not sure that is completely beneficial. It seems that one can not attempt to integrate the three without being declared null by one of their proponents. Now, instead of functioning together to develop well rounded observation and perspective, they compete for superiority, and attempt to usurp each other.

[CarolinaGuitarman]

"So which is it? If a *fact* cannot ever be proven 100% then how do you know that it's a fact?"

Because a fact in science is a data point, not an absolute. Data points are open to revision if new observations call for it.

"And if nothing is ever *proven* 100%, then why all the insults and derision towards those who are skeptical and don't accept it 100%?"

Just because something cannot be proven 100% like a mathematical theorem doesn't mean that a very high degree of confidence can't be had that it's correct. Mostly evos get critical of the convoluted ways that some anti-evos ignore what for most people who have examined the evidence is a very convincing explanation. I can't prove with 100 certainty that the sun will rise tomorrow, but I would think anybody who claimed it wouldn't was deluding themselves. I can't prove with 100% certitude that evolution is true; that doesn't mean that anti-evo positions have the same probability of being correct.

[William Terrell]

And just as soon as you show me how to create life. No demonstration, no explanation.

[RunningWolf]

Supposedly learned individuals put out this drivel and then other supposedly learned individuals soak it up like sponges

LOLOL America! That looks like something I would write, Kudos to you!

Well.. you really set them off this time. You know, I think there is a Dan-Rathersm somewhere in all of this that might well categorize their reaction here. I will get back to you on it!

Wolf

[CarolinaGuitarman]

"Pure chance organizing basic elements into the vast interactive systems evident now, plant, animal and insect?"

The laws of nature aren't random. Chemical reactions are not random. Natural selection isn't random. Your premises are all faulty.

ID is a *gaps* claim; any present gap in our knowledge is filled in with *the designer did it*. It is an unnecessary proposition that adds nothing to our understanding of the world. It's also untestable. While it may be true, there is no way to differentiate between a *designed* feature and a naturally occurring one in nature. That being the case, Occam's razor demands that ID be discarded until such time it makes a testable claim.

Occam's razor cuts for me, not you.

[dread78645]

"4 gills = 1 pint" placemark

[Dimensio]

Why, of course there is. The doctrine is found in all the writings and speeches of the major evolutionists for many years.

Perhaps you could outline this theory and provide references for it. It is and has been plainly stated by those who write in the field and those who teach it. The implication is a plain as arc light.

There are those who accept evolution and believe that no intelligence is behind the origin of life, however that does not make such a belief part of the theory of evolution, nor does that make such a belief a scientific theory itself.

Why do you care? Because they attack evolution?

Because they frequently spread misinformation, either because they themselves are misinformed or because they are dishonest.Evolution is attacking them.

Evolution is simply an explanation behind species diversity based upon observed evidence. It can "attack" no one.

[jec41]

They are separate because they are different methods. One can believe that 2+2=5 however it can be proved that 2+2=4 and is absolute. One can believe that the earth only exists in one's mind however it can be observed by many as a material fact. One can believe anything they wish of philosophy because it is faith and belief of things unknown.

[Dimensio]

Should such evidence of men creating self-sustaining life from basic elements and imbuing it with programed animation with survival and reproductive behaviors, and show how it could have started on its own, I don't see why not either.

Such an event would not be evidence that a similar event caused the first life on earth to exist.

[RunningWolf]

Paleontologists have studied different fauna and flora from different aged stratas, found different fossil remains, and have made INFERENCES as to the relation of the observed fossil finds

Thank You for that. I think the same way and have tried to say the same thing.

Wolf

[jec41]

And just as soon as you show me how to create life. No demonstration, no explanation.

Science doesn't have a observation of fact of creation or ID and does not claim how to create life. Creation and ID make such claims. Provide the observed material fact of ID or creation and how they created life.