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Tiktaalik

02/18/08 5:55PM By Ruth Page
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(HOST) Commentator Ruth Page has been following environmental issues from her home in Vermont for many years, and she has a fondness for unusual creatures. Recently, she's been reading up on one that's as strange as it is important.   

(PAGE) It's a really weird-looking fossil from some 375 million years ago, during the Devonian Era. It's obviously a fish, but a mighty strange one. Dubbed Tiktaalik (t i k t a a l i k), it has a neck, so it could lift its head independently of its body. Tiktaalik also had a spiracle atop its head, suggesting that it had primitive lungs as well as gills. It had a functional wrist joint, and simple finger and foot bones inside its fins.

Undeniably a fish, it clearly could have pulled itself up on land and lifted its strange, flat head to look around. Scientists discovered the odd fossil in 2004, far north on Ellesmere Island in Nunavut, Canada. Some called it a fishapod because it was a kind of missing link between fish and tetrapod (tetra for four, pod for foot). There were land plants nearby, the lower leaves of which it may have nibbled. Science has had a lovely time speculating about all the possibilities.
 
Scientists don't call Tiktaalik a missing link between water-life and land-life because there must have been other forms leading to such an enormous change. They believe they'll find additional fossils in future to help fill in the time-line. Such creatures appear to have been the beginning of the enormous variety of four-footed animals that later filled the millions of niches on land. It led to an enormous, branching tree of life, on one branch of which developed the genus Homo.
 
I find it fascinating, as Mark Twain might have said, to meet through the scientists' eyes my incredibly ancient fore-parent. It's rather nice to think of evolution coming up with a way to develop four-footed land creatures from finned fish.       
 
One of the great advantages of such finds as Tiktaalik is that each one fills a gap in the evolutionary record and reduces the power of creationists to dismiss the validity of Darwin's theory out of hand. Once again science has found clear evidence of gradual developments that led to immense changes. It makes me wonder how much more proof we need before Darwin's theory is accepted as proven. How about the Theory of Gravitation? Does that need more proof?
 
Every new-found fossil adds to the evidence supporting the theory of evolution. And, in fact, most scientists and billions of people around the world consider that it has been satisfactorily proven, though details have been added to it since Darwin's day in the 19th century.
 
Many scientists today are annoyed that they still have to defend it as an idea needing further testing. Scientific theories are not mere speculation. The purpose of publishing them in the scientific record is to allow them to be tested by other scientists over many years. Once that has happened, they are generally accepted as Truth.
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