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.
"Call me stupid (which I'm certain you will), but I thought is was witty and funny."
Humor has to have some basis in reality. The post in question didn't.
Of course his wife was his cousin, so we might guess what he had on his mind during those long years away from England, cozy warm fires, and big fluffy beds.
Hmmmm.
He must have been all science, hunh?!
"Just remember, evolution is ONLY a theory."
So does this mean they still will call evolution a theory, or is it now a "fact?" (tongue in cheek)
J. Craig Venter
Reread post #530.
So does this mean they still will call evolution a theory, or is it now a "fact?" (tongue in cheek)
Sun, long time no hear.
Check out the updated definitions list. Both "theory" and "fact" are there. I posted these to YellowDogHunter in #52, but they were soundly ignored for nearly 500 posts. What do you think?
Definitions (from a google search, with additions from this thread):
Theory: a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena; "theories can incorporate facts and laws and tested hypotheses." Addendum: "Theories do not grow up to be laws. Theories explain laws." (Courtesy of VadeRetro.)
Theory: A scientifically testable general principle or body of principles offered to explain observed phenomena. In scientific usage, a theory is distinct from a hypothesis (or conjecture) that is proposed to explain previously observed phenomena. For a hypothesis to rise to the level of theory, it must predict the existence of new phenomena that are subsequently observed. A theory can be overturned if new phenomena are observed that directly contradict the theory. [Source]
When a scientific theory has a long history of being supported by verifiable evidence, it is appropriate to speak about "acceptance" of (not "belief" in) the theory; or we can say that we have "confidence" (not "faith") in the theory. It is the dependence on verifiable data and the capability of testing that distinguish scientific theories from matters of faith.
Hypothesis: a tentative theory about the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena; "a scientific hypothesis that survives experimental testing becomes a scientific theory"; "he proposed a fresh theory of alkalis that later was accepted in chemical practices."
Proof: Except for math and geometry, there is little that is actually proved. Even well-established scientific theories can't be conclusively proved, because--at least in principle--a counter-example might be discovered. Scientific theories are always accepted provisionally, and are regarded as reliable only because they are supported (not proved) by the verifiable facts they purport to explain and by the predictions which they successfully make. All scientific theories are subject to revision (or even rejection) if new data are discovered which necessitates this.
Law: a generalization that describes recurring facts or events in nature; "the laws of thermodynamics."
Model: a simplified representation designed to illuminate complex processes; a hypothetical description of a complex entity or process; a physical or mathematical representation of a process that can be used to predict some aspect of the process.
Speculation: a hypothesis that has been formed by speculating or conjecturing (usually with little hard evidence). When a scientist speculates he is drawing on experience, patterns and somewhat unrelated things that are known or appear to be likely. This becomes a very informed guess.
Guess: an opinion or estimate based on incomplete evidence, or on little or no information.
Assumption: premise: a statement that is assumed to be true and from which a conclusion can be drawn; "on the assumption that he has been injured we can infer that he will not to play"
Impression: a vague or subjective idea in which some confidence is placed; "his impression of her was favorable"; "what are your feelings about the crisis?"; "it strengthened my belief in his sincerity"; "I had a feeling that she was lying."
Opinion: a personal belief or judgment that is not founded on proof or certainty.
Observation: any information collected with the senses.
Data: factual information, especially information organized for analysis or used to reason or make decisions.
Fact: when an observation is confirmed repeatedly and by many independent and competent observers, it can become a fact.
Religion: Theistic: 1. the belief in a superhuman controlling power, esp. in a personal God or gods entitled to obedience and worship. 2. the expression of this in worship. 3. a particular system of faith and worship.
Religion: Non-Theistic: The word religion has many definitions, all of which can embrace sacred lore and wisdom and knowledge of God or gods, souls and spirits. Religion deals with the spirit in relation to itself, the universe and other life. Essentially, religion is belief in spiritual beings. As it relates to the world, religion is a system of beliefs and practices by means of which a group of people struggles with the ultimate problems of human life.
Belief: any cognitive content (perception) held as true; religious faith.
Faith: the belief in something for which there is no material evidence or empirical proof; acceptance of ideals, beliefs, etc., which are not necessarily demonstrable through experimentation or observation. A strong belief in a supernatural power or powers that control human destiny.
Dogma: a religious doctrine that is proclaimed as true without proof.
Based on these, evolution is a theory. CS and ID are beliefs.
[Last revised 2/23/06]
Some of them are necessary precursors to life ~ stuff happens it turns out.
---"This one had the beginnings of upper arm, forearm and wrist joints on it's pectoral fins. That's the significant difference.
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."---
Wow. This is a great find! Now we know how animals went from living on land to living in the seas! Their forearms, shoulders, and wrists eventually gave way to fins!
A great discovery!
Abandoning thread. Night all.
It's coincidental that his methods resemble the modern approach.
Where he stepped off the planet was with his sexual selection theories ~ although they are still popular, other, more rational bases for the observations keep getting thought up. Remember, for Darwin, long separations from his wife may have given him a lot of ideas. With the animals, it's simply chemistry.
It might be your chemistry. Opinion seeks agenda by accusation and misinterpretation and is void of fact or knowledge.
The scientific method will not enable you to hold exact opinions on matters in which you lack sufficient data, but it can keep you from being certain of your opinions and make you aware of the value of your data, and to reserve your judgment until you have amplified your data.Robert A. Heinlein to John W. Campbell, in a letter dated 04 January 1942, reprinted in Grumbles From The Grave, pg. 33
Belief gets in the way of learning.Robert A. Heinlein, Time Enough for Love, 1973
Got a problem with any of this?
You are guilty of trying to reason with one that is crazy or insane. The definition of both is inability to reason. Waste of time.
What do you mean by simple and complex? There is not necessarily more information in the single celled human embryo than there is in the single cell of the amoeba. The amoeba has a larger genome.
Different information, perhaps, but not more.
The fulcrum of the argument is to consider the universe primarily as an artistic or creative feat, rather than as a work of engineering.
Two additional notes:
1) It would be very helpful for many of the disputants on these threads to read another of the essays in the book, "Problem Picture". It is a very lucid exposition of the difficulties of presenting the scientific mindset to a non-scientific world.
PLOT SPOILER BELOW!!!
2) Dorothy Sayers is most famous as a novelist (Lord Peter Wimsey) after having attended Oxford. It speaks to her scientific literacy that she made the key to one of her mystery novels the presence of a racemic mixture of enantiomers of synthetic muscarine. In a novel written in 1930...
It is my opinion that the point raised by Prout is the most accurate metaphysical division between the creationists and scientists: If God did make the universe, why did he lie? The answer presented by Prout is that God didn't lie, he made a work of art. And the mistake, according to this alternative point of view, is to have taken the indications in the art seriously.
For the fundamentalist cre's on the thread, there might be some analogy applicable here to the scripture "he catches the wise in their craftines..." But I'm not sure if it is necessarily applicable, so don't flame with it.
Cheers!
Cool stuff! Of course, the science content will be lost on the 5000 year old Creationist luddite nuts.
Lungfish:
Is that the imported thing that's been in Maryland's waterways that is eating everything in sight and can crawl across ground to new waterways?
Just for the record....
Does this suggest that man evolved from modern chimpanzee?
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