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 does. You are still riding a donkey and following a goat?
Independently, by each observer. Note we are dealing with a strict dichotomy. We are also dealing with a huge lack of direct, experiential knowledge as to what ultimately drives the universe.
If God is natural, then what is supernatural? There is a problem with defining natural as only that which can be understood by human reason, at least from an empirical standpoint. The problem is that we have no way of determining whether our definition of natural coincides with objective reality.
In addition to that, the dichotomy invites a tautology: We end up saying science can only deal with only natural phenomena while at the same time defining "natural" as only that which science can apprehend. How can science know for sure it is not the "nature" of things to fly apart without reason and disintegrate into nothing intelligible?
Beer is good first aid.
you are welcome, though i suspect I didn't state my point clearly enough. It is not that the particular breed of believer would say that God lies, but that "God lies" is, for them, an inescapeable corollary of the evidence indicating what science says it does. So they deny that the evidence says what science says it does, out of theological necessity.
All because of their (to my eye) false dilemma.
now - a semi-related tangential issue: take a look at "massive"
"massive" is a computer program developed to automatically simulate extremely large numbers of massed INDIVIDUAL combatants for the battle scenes of the Lord of the Rings.
for each species or race, several ranges of physical and behavioral characteristics were developed.
Each individual simulant was given a randomly selected value in each range. These mixed-bag values were intended to create variance between the movement speeds and styles of the combatants, so that the simulants looked and moved like live extras instead of a bunch of, well, computer-generated simulants.
But... it generated a surprise side effect: some of the simulants FLED the battlefield. The programmers were quite surprised by this behavior. But they let it stay, as it adds a little more realism to things.
Now, I will not say that this is an example of "free will"
What I will propose is that this is an example of semi-random assemblages of ranges of standardized components producing unanticipated and apparently "designed" or intended results.
I will also go so far as to wonder... If this illusion of free will derives from combinations of basic elements, what other behaviors which we *do* call free will are in fact just as illusory?
You have a method to determine opinion and what some one does not know or can't be observed?
see 1063 - the "either Genesis is 100% factual, or God Lied" dilemma is faced only by some breeds of believers. others have no such problem.
My Savior rode a donkey and gave His life for me. He is the same One who made the heavens and the earth and all that is contained therein, and still sustains them. Therefore I am not worthy to ride a donkey. I am not even worthy to breathe a single breath of life.
But you? Since you hold the key to history and know what is best for the education of all the children in our land, I suppose I should wear knee pads and kneel to your noodley ideology. No thanks. You can be the goat and kiss my grits. I know where I'm going, and it ain't on my own account. As for you, I guess you'll have to settle. Have fun.
I was just responding to the dare of whether or not it could be argued through induction, as opposed to deduction.
HAH! I got the Battle Of Hastings Prime!!!
What does any observer have to evaluate the substance that presents itself to reason and senses? Only a single mind that resides within the observer himself. That makes for messy science.
Oh. Wait. There are other observers who cropped up by nature, all unintelligiently undesigned, who might have something to offer as corroboration. Listen to them!
I do believe in absolutes and objective reality. I guess I should have added the sarcasm tag concerning that statement. I've had the *there are no absolutes* used on me often enough.
I think, however, that being truly objective is very difficult. Our point of view tends to color what we see way too much and there's always room for error because there's always some decision made that is just a matter of judgement. Our interpretation is often colored by how we feel, or what we're thinking of at the moment.
I am only stating what science has observed. This is not my opinion.
GG is absolutely great - but not cheap!
There are a couple of other companies now marketing the generic at about 30-40% cheaper.
Appears to work just as good as GG.
Do NOT buy a big bottle to get the savings of bulk if you can't use most of it within 1-2 months, for if a duffus forgets the LID sometime, the saving turns into real hard cash!
"And another thing. It is easy to understand. Anyone can become an evolutionary biologist in an afternoon. Just read a book. Most of them are half illustrations anyway. Its not like studying mathematics or physics, lot of head splitting stuff there.
"It is thus infinitely droll to see evolutionary biologists restrain themselves from debating the issue on the grounds that the public is apt to get confused. And God Knows, theres no need to confuse the public so long as they keep those swell funding checks coming." - Dr. David Berlinski
These?
Check close again: do they STILL look like mutant rats??
And if you found some, frozen in stone, you'd STILL get a bunch of folks arguing over just what their 'message' really is!
NOW you've REALLY piqued our (mine anyway) curiosity!
Beautifully put! All because of their (to my eye) false dilemma.
One of the other conudrums is that contradictory evidence based upon empirical studies are NOT fatal to science, because science claims to be *A MODEL* and hence subject to revision. Revealed truth based upon authority claims to be, well, revealed. So one way out is to say "well, it's only *moral* truth, which then runs the risk of making "spritual" become roughly synonymous with "Pickwickian"...
If this illusion of free will derives from combinations of basic elements, what other behaviors which we *do* call free will are in fact just as illusory?
That would be more powerful if "free will" had been posited upon observations of others, rather than (say) the Cartesian je pense, donc je suis.
And then you get into the entire Red Herring, Pandora's Box, Troll Garden extraordinaire of "what is *will*"?, how "free" is it (running the gamut from "totally free" to "conditioned" to "automaton"...
and from there it is but a short step (fall?) to Free Will vs. Predestination, etc.
I mean, come on, this thread's already over 1,000 posts as it is, and I'm too tired to read the last 500 right now :-(
But about the automatons, you could do some nifty stuff in *simulating* evolution if you tweaked the program. In particular, sensitivity analysis on the parameters, to see what combinations led to the aforementioned "Brave Sir Robin" behaviour...which might have *temporary* survival value. The problem is that so much of the behaviour is so dependent on the values of the parameters chosen, (think analogies to semi-empirical molecular modeling), that it has little *direct*, *specific* (ab initio) predictive value...
...and thereby hangs a tale.
Cheers!
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