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.
Oh ok. Yes I guess I'm a bit slow. I thought we were having a discussion, how dumb of me. You are obviously the All Seeing Omnipotent One That Knows All And Can't be Bothered with Petty Questions or Theories or Other Trains of Thoughts. Excuse the ring. Did not mean to interfere on your one way street of superior intelligence.
If you don't know anything at all about what evolution says happened and how, how do you know it's wrong?
You are using a tautology to 'splain a tautology. Does not compute.
Is there a point to this? You didn't answer my original question regarding what resources sharks and marsupials would have been competing for that would have compelled the marsupials to drive the sharks off the Austrailian land and banish them to bear their young in the water.
Because it makes him feel icky.
That's the point of the piece. Everything else nestles within.
We simply cannot revise what Darwin understood as "evolution" to mere change.
"Why can't you stipulate an intelligent designer if you would have me stipulate a proto-organism? "
I don't rule it out, but there is no necessity for it. There is no need for that proposition.
Can we do it in vitro?
Time to post this yet again:
Here is my own example of gravity:
A little history here:
Newton’s Law of Universal Gravitation
“Every object in the universe attracts every other object with a force directed along the line of centers for the two objects that is proportional to the product of their masses and inversely proportional to the square of the separation between the two objects.”
F=Gm1m2/r2
Where:
F equals the gravitational force between two objects
m1 equals the mass of the first object
m2 equals the mass of the second object
R equals the distance between the objects
G equals the universal constant of gravitation = (6.6726 )* 10-11 N*m2/kg2 (which is still being refined and tested today)
(BTW this is a simple form of the equation and is only applied to point sources. Usually it is expressed as a vector equation)
Even though it works well for most practical purposes, this formulation has problems.
A few of the problems are:
It shows the change is gravitational force is transmitted instantaneously (Violates C), assumes an absolute space and time (this contradicts Special Relativity), etc.
Enter Einstein’s General Theory of Relativity
In 1915 Einstein developed a new theory of gravity called General Relativity.
A number of experiments showed this theory explained some of the problems with the classical Newtonian model. However, this theory like all others is still being explored and tested.
From an NSF abstract:
“As with all scientific knowledge, a theory can be refined or even replaced by an alternative theory in light of new and compelling evidence. The geocentric theory that the sun revolves around the earth was replaced by the heliocentric theory of the earth's rotation on its axis and revolution around the sun. However, ideas are not referred to as "theories" in science unless they are supported by bodies of evidence that make their subsequent abandonment very unlikely. When a theory is supported by as much evidence as evolution, it is held with a very high degree of confidence.
In science, the word "hypothesis" conveys the tentativeness inherent in the common use of the word "theory.' A hypothesis is a testable statement about the natural world. Through experiment and observation, hypotheses can be supported or rejected. At the earliest level of understanding, hypotheses can be used to construct more complex inferences and explanations. Like "theory," the word "fact" has a different meaning in science than it does in common usage. A scientific fact is an observation that has been confirmed over and over. However, observations are gathered by our senses, which can never be trusted entirely. Observations also can change with better technologies or with better ways of looking at data. For example, it was held as a scientific fact for many years that human cells have 24 pairs of chromosomes, until improved techniques of microscopy revealed that they actually have 23. Ironically, facts in science often are more susceptible to change than theories, which is one reason why the word "fact" is not much used in science.
Finally, "laws" in science are typically descriptions of how the physical world behaves under certain circumstances. For example, the laws of motion describe how objects move when subjected to certain forces. These laws can be very useful in supporting hypotheses and theories, but like all elements of science they can be altered with new information and observations.
Those who oppose the teaching of evolution often say that evolution should be taught as a "theory, not as a fact." This statement confuses the common use of these words with the scientific use. In science, theories do not turn into facts through the accumulation of evidence. Rather, theories are the end points of science. They are understandings that develop from extensive observation, experimentation, and creative reflection. They incorporate a large body of scientific facts, laws, tested hypotheses, and logical inferences. In this sense, evolution is one of the strongest and most useful scientific theories we have."
I didn't bring up sharks. You did. You will have to explain how it came to be that there were sharks wandering around with the marsupials.
If you don't know anything about anything then how do you know anything? How do you know if its right or wrong? You don't want to have a discussion but call people "dumb", like you said I was, that don't agree with you. I'm done with you. Don't reply, ping me, nothing. Go evolve into the next super species. That's your real calling.
Why are people dealing with geology, rocks, and fossils? The flood is commonly accepted to be about 4350 years old. You should be dealing with soils!
You need to talk to the archaeologists, not the geologists!
We have a good continuous record in the western US of human habitation (including mtDNA, archaeology, settlement and subsistence strategies, etc.), faunal and floral succession (pollen records, tree rings from bristlecone pines, etc.), sedimentology, and a lot more. And this is in the soils.
There is simply no room for a global flood, with total population and faunal/floral replacement, and immense erosional forces acting on the soils. The evidence is simply not there.
Yes, and yes.
Now, real quick, where's the seat of consciousness, and do single celled animals have one?
Hah! It's probably an emergent property, and it's also something that the theory of evolution does not currently address and possibly never will.
I thought of another thing regarding genes and relatedness. You seem to be an ID proponent rather than YEC? The typical ID spokespersons do accept descent from a common ancestor, but while evolutionists say that this could happen via natural means (not excluding God here, there are theistic evolutionists who believe this, just as there are those who believe God controls the weather even though he does so through natural means) the ID people insert little kicks into the system on occasion. So we need eukaryotes--here's a kick! Multicellularity--another kick! Accepting ID as it is currently proposed implies accepting common descent.
So the trouble with saying that God (oops, I mean the Designer) made all of these organisms with slightly different gene sequences for whatever reason and it is not a hint at relatedness is that most ID and many YEC proponents do allow for some speciation. Those who do would see no problem with setting up a phylogeny based upon multiple gene sequences for a group of animals they think are related. But then we aren't allowed to take a further step and compare groups that that particular IDer does not think are related? Why not? The point at which a IDer/YEC will say "No more!" varies from person to person. One person I almost got to agree that it could be that felines and canines were related. Others won't even admit foxes and wolves are. It is all quite arbitrary!
So logically it seems there are only two internally consistent paths--either accept zero speciation or accept common descent by countless kicks. Ouch.
It was interesting.
My preface was that according to the evolutionist tadpole-to-human theorists, like yourself, anything is possible. I said that right up front. I also said in several posts that I don't know why there is no link between egg laying mammals and those who lay eggs in trees, such as birds. Scientists can't provide that link. I'm not having a discussion with you yahoos who don't want to engage in discussion. I believe you all think you have hidden gills somewhere that evolved into testicles. The best YOU and your kind can provide is that I am dumb and contradict myself. None of you have provided anyting that explained how we got from fish to man EXCEPT some theory. Yet when some other theory or question is interjected into your frail little scenario, you start bullying instead of discussing. So go talk amongst your own holier than thou selves. Post all your charts, pictures and scientific evidence (with links) as definitive proof for all us dummies. Thanks much!
p'raps... but I may be too tired to appreciate it. going to bed. c ya.
The idea is that some processes can be performed ONLY by a gene with certain sequences, and where they are obtained are irrelevant to how they work.
An analogy would be automobiles and carburators. Just because all cars (used to) have carburators does not mean they are all the same make.
We are probably going to have to face this problem when we meet our first life forms in the far reaches of space.
See posts #52 and 459.
Your opinion.
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