This blog is based on a program that aired April 9, 2014 on PBS, titled Your Inner Fish. Back in 1999, Fish Paleontologist Neil Shubin and some associates started a search that would last ten years. They wanted to find a fossil of an amphibian that would show there was a link between modern fish and Ichthyostega, a type of salamander with a skeletal structure that was ultimately related to the human skeleton. They expected the link would demonstrate how primates, including humans, were physically evolved from fish.

Since fish existed 400 million years ago, and the missing link would have evolved 40 million years after that, they would have to find rock formations that were around 360 million years old. Surprisingly, they knew of such a rock outcropping here in the U.S. The location was called Red Hill, located along a major highway in Pennsylvania. Although their search produced fossils from that timeframe, they did not find what they were looking for. They also looked in places like Ethiopia, and Nova Scotia but without success.

Finally, in July of 2000, they found what they were searching for. Unfortunately the area was located in northern Canada where there were no roads, no people, and no sources of food; plus there were polar bears. The worst news was that the area lay under a thick covering of snow in frigid temperatures most of the year. The only time they could search the area was July. So that’s what they did for four years before finding a river bed filled with the type of fossils they were looking for in 2004. That was when they uncovered a complete, intact fossil of a flat-headed fish nine feet long.

The fossil was the first fish-like amphibian that had a common bone structure with every reptile, bird, and mammal that has ever existed; including humans. And in every one of the life forms just mentioned the similarity begins at the main body, growing into a single bone, followed by two bones, followed by many bones, and finger-like or toe-like bones. The cause of this similarity is found within a single gene in our DNA. This skeletal structure is common to the feet of mice, the hands of humans and the arm and leg structures of all four-legged animals. So this 360 million year old fossil was the first of its kind to make the transition from fish to amphibian. It set the stage for a transition to a whole new set of physical characteristics that would ultimately result in mankind; you and me.

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