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.
seems a lot of folks are determined to misunderstand what I stated.
I will state it again:
whenever theories go beyond what is testable, there is no difference between such theories and supernatural explanations.
additionally:
Everything which is testable has always been testable and will always be testable (provided no change in basic conditions, of course) irrespective of the level of technology in man's arsenal.
This has -or so it would seem- led some folks to make some rather snarky assumptions and cast some rather stupid aspersions ("masters of the universe" et alia).
TRY TO READ WHAT IS STATED.
I'll help, with an illustration:
On an airstrip sit two objects.
One is a fuelled and fully functional top-of-the-line single-seat fighter aircraft.
The second is cube of an equivalent mass of basalt.
The aircraft is capable of being flown, irrespective of whether or not there is anyone on Earth capable of flying it. It is and shall remain flyable, independent of human know-how.
The basalt cube is not capable of being flown, ever, period, paragraph, full stop. It is and shall remain un-flyable, independent of human know-how.
That a thing is flyable in no way implies that humans will ever develop the capability to fly it. Humans fail all the time - no reason at all to assume they will succeed in doing a thing simply because it is doable.
Place the airfield as described above in pre-colonial New Guinea, and posit no foreign interference:
Odds are against any of the natives recognizing the plane as a vehicle, let alone that it can be flown, let alone figuring out how to fly it.
Indeed, as modern fighter aircraft more closely resemble sharks than birds, they could be more likely to think it a watercraft than an aircraft, if they see it as a craft at all.
BUT THE SAVAGES' LACK OF KNOWLEDGE DOES NOT DETERMINE WHICH OBJECT IS FLYABLE AND WHICH IS NOT.
Similarly with testability.
The technological achievement of science does not determine what is testable; it determines what tests we are cabable of making.
And just as familiarity with the principles of flight does allow a pilot to know an aircraft from an unflyable cube of basalt, so too does empirical science enable the scientist to tell a testable hypothesis from one which cannot be tested, ever.
In both cases, for pilot and scientist, there are gray areas - cases in which the thing under consideration *might* be flyable, in which an hypothesis *might* be testable. These things should neither be accepted nor rejected out of hand. They are interesting, potentially useful, potentially rubbish, but not immediately identifiably so.
The trick is to separate truly gray hypotheses from ones which, frankly, are cases in which people have, piecemeal and ad-hoc, built a plane around a cube of basalt.
ALL RIGHT KING.. lay off the dumberol that stuff'll make you ignert..
I'm not sure your analogy is sufficiently direct in this instance, King Prout. For one thing, the fact that some human beings in New Guinea would fail to recognize that the object that sits on their tarmac is a fighter jet does not mitigate at all against the truth that the jet was expressly, knowledgeably built for flight, and beyond that for military missions. In other words, to use the language of Aristotelian causation, the formal cause of the jet seeks fulfillment in a final cause (i.e., flight, military missions); and material and efficient causes were applied so as to achieve the aimed-for goal.
Any "gray area" involves the state of our knowledge regarding the object, not the object itself. The guy (team) who built the jet has no "gray area" respecting that particular jet. Does this make any sense at all?
Thanks so much for writing, KP!
I expected that one of you at least would attempt to extend the analogy beyond its specific intent.
the analogy *itself* is a construct of intelligence, betty.
that has no bearing on the matter (inherent testability or untestability) it illustrates through analogy.
The actual reality of an object that we'd like to test is independent of its testability or untestability. It is what it is regardless. We could try to test it, find we haven't got the means to do so, and still the object would be there. Presumably. :^)
Kinda reminds me of the problem of the "obelisk" in 2001: A Space Odyssey.
Am I splitting hairs here, or are you?
Thanks for writing, King Prout!
I'd also assert that, as a result of a test, we may conclude a thing is real only to discover by a subsequent test that it was merely an illusion.
Agreed, dear Alamo-Girl! I suppose this sort of thing can occur, depending on what other "undisclosed premises"/personal baggage got loaded into the first inquiry, right up-front.
Thanks so much for your excellent observation!
My grey hypothesis is this:
You hit the nail on the head earlier with your description of the possible way out of the conudrum, by the analogy to the past lives of characters in a novel.
Which leads to this post, there is no way to test the hypothesis.
Full Disclosure: Incidentally, it is the inability of "the scientific method" to differentiate between the untestable which gives the Flying Spaghetti Monster its ZING!
Cheers!
"An inventor can advance step by step in the construction of an airplane even if he is only experimenting with sticks and scraps of metal in his own backyard. But he cannot watch the Missing Link evolving in his own backyard. If he has made a mistake in his calculations, the airplane will correct it by crashing to the ground. But if he has made a mistake about the arboreal habitat of his ancestor, he cannot see his arboreal ancestor falling off the tree. "
See the full link here.
I don't think this argument is as cogent as it once was, because with the advent of molecular biology and genetics we are in principle able to avail ourselves of "universals" (laws) governing the behaviour of some aspects of that which we are attempting to model.
However, the warning is true insofar as evolution is something taking place in vivo rather than in vitro. So if one oversimplifies the models, does not correctly model the environment, what have you, the specific predictions may well go awry, and one is left with something which isn't even semi-empirical, but is more ex post facto hand waving...
And it is there that Chesterton's warning still stands.
Speaking of which, Chesterton inluded in one of his short stories The Strange Crime of John Boulnois) the concept of catastrophism in which he posited (as a minor part of the plot) that evolution occurred more or less in fits and starts, rather than gradually and at a more or less constant rate...the book was written in 1914.
Cheers!
This sounds like it was inspired by Feynman's "cargo cult science" which he used to describe psychology, but which I think has applicability to ID...
Cheers!
"whenever theories go beyond what is testable, there is no difference between such theories and supernatural explanations."
Allow me to look at this statement a minute.
What if that statement is true?
To determine the origin of the earth is not testable.
Therefore, any theories concerning the Origin of the Earth have equal standing as any supernatural explanation.
If this is true, then Theories of the Origin of the Earth and Intelligent Creationism should be taught side by side.
Are you really sure this is the outcome you want?
If you analyze the situation you are now in then you must come to the conclusion that BEING ABLE TO TEST SOMETHING IS NOT A GOOD FOUNDATION ON WHICH TO ACCOUNT FOR ALL THE MANY MYSTERIES OF LIFE ON EARTH.
The mere act of TESTING is actually a comparison of one thing to another. There is no way for a human to KNOW the entirety of anything by measuring or testing.
Them's my sentiments.
Perhaps this post is a little more testing than you want.
Could that mean you are supernatual?
This is all in fun. No offense intended.
What is your Theory of Love? Is it possible to test Love and yet it remains and you must go beyond testing and then again we come head on into the Supernatural.
Funny, We think the Supernatural is not testable.
Can you tell me the intrinsic and full value of a one dollar bill? You will not come to a conclusion using testing. Is the dollar Supernatural?
These are not frivoulous questions. They are unusual admittedly.
I have heard it called the "almighty dollar". My kid can find out its worth and value at the store down the street.
The canned answer is "survival value" but it's kinda short on specifics. (Why DO gentlemen prefer blondes? Has anyone really tested the idea of greater hardihood or healthier young or whatnot?)
Please ping whoever I missed ;-)
Cheers!
Such a gracious response to my coarse rantings. I see your "middle" name is Christian. Mine too.
Without Him I am unable to see, hear, or breath. My heart beats because of Him.
In that great gettin' up morning we will know Him as He really IS.
I will see you there Alamo Girl.
"Are you saying that Darwin thought the body was made of one big cell? Or are you saying that Darwin didn't know of the 200-300 different types of cells that make up the body?"
Darwin thought the body was made up of one or a few cells, when actually there are TRILLIONS of cells.
"So what? The theory of eovlution does not require the existence of cells. It requires heritability, variability, and natural selection.
By the way, are you going to acknowledge you misrepresented that webpage?"
"misrepresented" is a little harsh, and I thought you were one of the nicer evos. I'm still waiting for all of the many evos that attacked me, called me names, ATTEMPTED to put me down, etc. for saying that the body has TRILLIONS of cells to admit that I was correct. Darwin convinced scientists of evolution based on the antiquated information that the body only had one cell, so it IS important.
ALSO, the core of evolution is that one species can become an entirely different species.
What got me to first delve into the fact that there has been no proof that one species can become an entirely different species is when I read it in a book by Judge Bork. Judge Bork is not someone who is devoting his life to the ID theory, but wrote a book on a number of things covering culture, the Constitution, etc. He only devoted one or two pages to his "there is NO PROOF that one species can become another species" view out of his entire book, hardly a person who is devoting his life to ID, so probably at one time quite open-minded about the evo theory.
I'd say he is one of the smartest, well educated, well-informed persons in this country, so his view should be respected, even for those who don't agree with him.
Evo requires going across the species line, not developing variations within it.
Well, Running Wolf, the evos fought me tooth and nail when I said that the body is made up of TRILLIONS of cells. So when I finally gave them two sources, they said, it doesn't matter anyway. So why did they fight me tooth and nail if it doesn't matter?
Here's one source:
Dear Yahoo!: My 7th-grade class wants to know approximately how many cells make up the human body. David
Aurora, Colorado Dear David: That's a very good question, and we applaud your class for its inquisitiveness. We knew there were a lot of cells in the human body, but we were hard pressed to put an actual number on it. It seemed like a fairly straightforward query, so we tried a straightforward approach and typed "number cells human body." Our results were numerous and informative, but after flipping through them, we learned there really is no consensus on the answer.
Some sources told us that the average adult human body is made up of "50 million million" (50 trillion) cells, while others put the figure closer to 10 trillion. Science NetLinks, a resource for science teachers, stated that there are approximately "ten to the 14th power" (that's 100 trillion) cells in the human body.
http://ask.yahoo.com/20020625.html
I didn't say you deliberately misrepresented it. Being wrong is bad enough; your motives are secondary.
Darwin convinced scientists of evolution based on the antiquated information that the body only had one cell, so it IS important.
If you can't speak for speaking nonsense, maybe you should realize that?
I'd say he is one of the smartest, well educated, well-informed persons in this country, so his view should be respected, even for those who don't agree with him.
I like Judge Bork. I heard him speak about 10 years ago, and it was one of the wittiest, funniest speeches I've ever heard. Even the liberals in the audience were having a tough time holding it in.
That being said, his opinion on biology is probably less valuable than my opinion on Constitutional Law, because I can recite most of the Constitution from memory, and I doubt he's ever cracked a biology text. I'm not saying laypeople shouldn't have an opinion on biology. But what is it about biology, or them, that makes them think their opinion is worth anything, if they don't know any biology?
Sun says: Darwin convinced scientists of evolution based on the antiquated information that the body only had one cell, so it IS important.
RWP says: If you can't speak for speaking nonsense, maybe you should realize that?
But yet, you can't refute what I said, can you?
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