Scientists Discover “Missing Link” Between Fish and Land Animals!

Tiktaalik roseae

How did early fish evolve to survive on land?

One of the greatest fulfilled predictions of evolutionary biology is the discovery, in 2004, of a transitional form [“missing link”] between fish and amphibians. The discovery of Tiktaalik roseae is a stunning vindication of the theory of evolution.

[The fossil record indicates that] until about 390 million years ago, the only vertebrates were fish. But 30 million years later , we find [in the fossil record] creatures that were clearly tetrapods: four-footed vertebrates that walked on land. These early tetrapods were like modern amphibians in several ways: they had flat heads and bodies, a distinct neck, and well-developed legs and limb girdles. Yet they also show strong links with earlier fishes, particularly the group known as “lobe-finned fishes,” so called because of their large bony fins that enabled them to prop themselves up on the bottom of shallow lakes and streams. The fish-like structures of early tetrapods include scales, limb bones, and head bones.

If there were lobe-finned fishes but no terrestrial vertebrates 390 million years ago, and clearly terrestrial vertebrates 360 million years ago, where would you expect to find the transitional forms? Somewhere in between. Following this logic, University of Chicago scientist, Neil Shubin predicted that if transitional forms [“missing links”] existed, their fossils should be found in [sediment] strata around 375 million years ago. Moreover, the rocks would have to be from freshwater rather than marine sediments, because lobe-finned fish and early amphibians both lived in fresh water.

Searching his college geology textbook for a map of exposed freshwater sediments of the right age, Shubin and his colleagues zeroed in on a paleontologically unexplored region of the Canadian Arctic: Ellesmere Island, which sits in the Arctic Ocean north of Canada. And after five long years of fruitless and expensive searching, they finally hit pay dirt: a group of fossil skeletons stacked one atop another in sedimentary rock from an ancient stream. When Shubin first saw the fossil face poking out of the rock, he knew that he had at last found his transitional form [“missing link”].

Reconstruction of Tiktaalik roseae

[The fossil he found] Tiktaalik roseae has features that make it a direct link between the earlier lobe-finned fish and the later amphibians. With gills, scales, and fins, it was clearly a fish that lived its life in water. But it also has amphibian-like features. For one thing, its head is flattened like that of a salamander, with the eyes and nostrils on top rather than on the sides of the skull. This suggests that it lived in shallow water and could peer, and probably breath, above the surface. The fins had become more robust, allowing the animal to flex upward to help survey its surroundings. And, like the early amphibians, Tiktaalik has a neck. Fish don’t have necks—their skull joins directly to their shoulders.

Most important, Tiktaalik has two novel traits that were to prove useful in helping its descendants invade the land. The first is a set of sturdy ribs that helped the animal pump air into its lungs and move oxygen from its gills (Tiktaalik could breath both ways). And instead of the many tiny bones in the fins of lobe-finned fish, Tiktaalik had fewer and sturdier bones in the limbs—bones similar in number and position to those of every land creature that came later, including ourselves. In fact, its limbs are best described as part fin, part leg.

Tiktaalik…is a fossil that marvelously connects fish with amphibians. And equally marvelous is that its discovery was not only anticipated, but predicted to occur in rocks of certain age and in a certain place.

—biologist Jerry Coyne, Why Evolution is True, pp 35-38

Why Evolution Is True: Coyne, Jerry A.: 8601400309193: Books







End of post.

7 thoughts on “Scientists Discover “Missing Link” Between Fish and Land Animals!

  1. Ah, yes. University level adult fantasies…none of which has ever passed through peer review as being proof for any one species evolving into another, but ignorant people believe there’s proof in spite of the reality. Aesop’s Fables has a better chance at passing peer review than this garbage.


    1. [N]one of this sits well with the Young-Earth creationist crowd, who are continually trying to undermine science education and US science literacy. What do creationists say about Shubin’s research, and especially Tiktaalik? Turns out that creationist leader Ken Ham of Answers in Genesis has his answer ready to go: “There are no transitional forms that support evolution,” he confidently declares in a minute-long audio track dedicated to debunking the Tiktaalik finding. Why? Because “the Bible says God made fish and land animals during the same week, not millions of years apart.” That’s just the beginning of the attempted takedowns that creationists have leveled against Shubin’s work.

      Creationists snipe, raise doubt, and deny almost everything that we know, but the reason that Tiktaalik is such a momentous find appears to be beyond them: Evolutionary theory (complemented by an extensive knowledge of geology) predicted not only that this fish would have existed, but also, that its fossilized remains would probably be found within a specific part of the world, in geological layers of a particular age. Hence, Shubin’s many trips with his team to the Canadian Arctic, where those rock layers could be found. “We designed this expedition with the goal of finding this exact fossil,” explains Shubin. “And we used the tools of evolution and geology as discovery tools to make a prediction about where to look. And the prediction was confirmed.” Thus, Tiktaalik isn’t just proof of evolution; it’s also proof that the scientific process works.


      Liked by 1 person

      1. “There are no transitional forms that support evolution,” he [creationist Ken Ham] confidently declares in a minute-long audio track dedicated to debunking the Tiktaalik finding. Why? Because “the Bible says God made fish and land animals during the same week, not millions of years apart.”

        In other words: “It can’t be true because my infallible ancient Middle Eastern holy book says it is false.”

        That is not rational thinking.

        Liked by 1 person

    2. For those keeping track, calling something a fantasy, calling some people ignorant, comparing something to Aesop’s Fables, and calling something garbage, do not make any sort of argument at all. There is no logic; it is merely name-calling. The only other part of swordmanjr’s post is a claim for which no support is offered.

      Liked by 1 person

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