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.
Hey, I'll openly admit that we certainly don't understand everything about how evolution occurred over the last 3.5 billion years (though we can say for sure that it has happened and continues to do so). It is good to question the assumptions about what we know in science, but if one expects an existing model to be replaced, one must offer up something better than the existing model that is capable of explaining more. That's what burns me about ID - it doesn't offer any explanations of how change occurs, and hasn't contributed anything other than pointing out we don't know everything yet (something we already knew!)
You make a good analogy to tectonics. Tectonics works in "spurts" - small "jolts" that over time add up to colossal changes - but it still, on average, is a gradual process. Evolution may work more in this manner than we think, but we're still talking about a gradual process when considered in the grand scheme of time. There certainly are many examples of documented gradualism known in evolution, but we don't know for certain yet that this type of change explains every instance of evolution, I would agree. This, though, is merely the meting out one of the finer details of the theory, not changing its basic precepts all together.
"It is sad to see conservatives so caught up in Hollywood that they cannot understand science."
What does one's being a conservative or liberal have to do with scientific facts?
Geologic Gradualism was dominant for a very long time. Louis Agassiz laid waste to that point of view ~ by demonstrating vast areas of glaciation.
At the same time he opposed the Darwinian view of "gradual change over time in some unknown way".
We can only imagine why he objected to gradualist philosophies.
In the the end the discovery of DNA put the sword to the unknown parts, and to the need for "gradual change". All you needed was a mutation, and it was Katy bar the door, eh?!
So, was Louis right or wrong when it came to Darwinian viewpoints?
Personaly I think the gradualist nonsense still infecting evolutionary theory is hanging on simply because we have modern antibiotics and the old fart$ are not dieing out fast enough. But, eventually, they will, and just in time for Mankind to take charge of his own genome.
Define simple.
What people say does not alter reality. Humans are considered more complex simply because that's been a cultural assumption for recorded history.
But ID advocates have brought information theory into the argument, and I'm asking, from the viewpoint of information theory, define simple and complex. Tell me how you measure information. Tell me how you determine the complexity of a genome.
You don't appear to take ID seriously, and I didn't address the question to you. I'm asking those who raised this issue earlier in the thread.
To a creationist, simple means the quickest way to end inquiry.
(Or generate Scripture verses ;^)
NIV Exodus 18:19-22
19. Listen now to me and I will give you some advice, and may God be with you. You must be the people's representative before God and bring their disputes to him.
20. Teach them the decrees and laws, and show them the way to live and the duties they are to perform.
21. But select capable men from all the people--men who fear God, trustworthy men who hate dishonest gain--and appoint them as officials over thousands, hundreds, fifties and tens.
22. Have them serve as judges for the people at all times, but have them bring every difficult case to you; the simple cases they can decide themselves. That will make your load lighter, because they will share it with you.
NIV 2 Kings 20:10
"It is a simple matter for the shadow to go forward ten steps," said Hezekiah. "Rather, have it go back ten steps."
NIV Job 5:2
Resentment kills a fool, and envy slays the simple.
NIV Psalms 19:7
The law of the LORD is perfect, reviving the soul. The statutes of the LORD are trustworthy, making wise the simple.
NIV Psalms 116:6
The LORD protects the simplehearted; when I was in great need, he saved me.
NIV Psalms 119:130
The unfolding of your words gives light; it gives understanding to the simple.
NIV Proverbs 1:1-7
1. The proverbs of Solomon son of David, king of Israel:
2. for attaining wisdom and discipline; for understanding words of insight;
3. for acquiring a disciplined and prudent life, doing what is right and just and fair;
4. for giving prudence to the simple, knowledge and discretion to the young--
5. let the wise listen and add to their learning, and let the discerning get guidance--
6. for understanding proverbs and parables, the sayings and riddles of the wise.
7. The fear of the LORD is the beginning of knowledge, but fools despise wisdom and discipline.
NIV Proverbs 8:5
You who are simple, gain prudence; you who are foolish, gain understanding.
NIV Proverbs 9:4
"Let all who are simple come in here!" she says to those who lack judgment.
NIV Proverbs 14:15
A simple man believes anything, but a prudent man gives thought to his steps.
NIV Proverbs 19:25
Flog a mocker, and the simple will learn prudence; rebuke a discerning man, and he will gain knowledge.
NIV Proverbs 22:3
A prudent man sees danger and takes refuge, but the simple keep going and suffer for it.
Christians are, in general, all over the place concerning new revelations. Moslems, though, are adamant ~ there are none.
Lately, its Blind men describing Immigrants.. Presidential Candidates, and Science.. it is indeed touchy feely intellectual 2nd realitys.. The 2nd reality is indeed a mask.. Masked men describing and deciding how to handle Islam etc... Not naturally blind but self induced blindness, by mask.. Thank God, God is control of all this.. Other than that there is reason to be very very afraid.. Self induced blindness is such a pitiful condition.. Worse many masks have eye holes in them.. And the blindness is not blindness at all, but malificence, on purpose..
You missed the point.
Oh?? ;^)
Or, at death, your consciousness will diminish to nothing, as your brain ceases to function and you'll never "know" anything again.
There are degrees of unreliability. Wikipedia provides cross references (fortunately), so go to the cross references.
"You missed the point."
What post are you referring to?
I simply pointed out that the anti-ID and anti-Creationist movement among evolutionists have made the argument that life cannot be observed as a fact in and of itself without reference to evolution.
Maybe you hadn't encountered those guys before.
Absolutely!!
NIV Proverbs 14:34
Righteousness exalts a nation, but sin is a disgrace to any people.
The old gradualist philosophy in geology held that mountains were all formed by weathering of surface rock.
That is your opinion of how you think things should be determined, but your opinion does not follow any of the three methods for acquiring knowledge.
Science only observes material facts, not stipulations. It does not stipulate anything but only provides evidence and empirical evidence that explains the fact. It has observed evolution as a fact. Creation is faith and belief in the unknown. Science cannot observe the unknown. It has no method for such. Creation remains faith and belief, not a observed material fact.
Still is. Your posts make no sense.
Gradualism is a misnomer anyway. The central premise of science is that past events can be explained by processes and phenomena that can be observed in the present. Some processes are slow and some are catastrophic, but they can be understood in current terms. Nothing you have said adds anything to the discussion.
Nah - we'll know.
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