May 24, 2023 | David F. Coppedge

Out On a Limb: The Evolution of Olympians

Pole vaulters, gymnasts, and hurdlers got their start
by accident inside a precocious fish, say evolutionists.

— A fish story that is a whopper of a non-sequitur extrapolated to absurdity —

Corel pro photos

Limbs: they allow us to leap, run, spin, work, and play. We rightly award the strongest, fastest and best who train for years to use their limbs in exceptional ways. What would the animal world look like without limbs?

Every land animal that moves on all fours—the tetrapods—has exactly the limbs appropriate for its life, equipped with bones, muscles, tendons, nerves, blood vessels, sensors, and a host of other essential parts. Other animals, the insects with six articulating limbs (hexapods), ten (decapods), or more (myriapods), move dexterously in their own habitats, fulfilling the function of movement their limbs provide.

Coordinated Development

Limbs cannot be considered in isolation. No limb would move without the entire body of the creature supporting it: brain, nervous system, respiratory system, circulatory system, sensory system, and digestive system. And because of the reproductive system, all these systems can be encapsulated into a single-celled gamete with the genetic instructions to regrow them back in the next generation. What a wonderful world we have because of limbs!

How did he do that?  Credit: Illustra Media

One other important trait of limbs is bilateral symmetry. Our limbs, and all the parts they contain, are mirror images of each other left to right. Imagine a bear trying to walk with four left feet, or a bird trying to fly with two right wings. The details of the symmetry are very exacting. The left femur has to have the same attachment points for tendons and muscles but on opposite sites of the bone from the right femur, while maintaining the correct top and bottom positions of the bone as well. Moreover, these attachment points and the muscles and tendons that attach to them must constantly adjust during development to the length of the bone as it grows radially at a different rate than it grows longitudinally. How does the left hand know what the right hand is doing? Somehow the parts end up matching almost perfectly. Put your hands together and notice how many details are perfect mirror images of each other.

Any explanation for symmetry has to account for the ability of the genetic code, without eyes to guide it, to ensure that every finger, tendon, toe, leg bone, muscle and blood vessel ends up on the correct side of the body and in the correct relationship to other parts. This is true for other symmetrical body parts, too, like ribs, kidneys, teeth and eyes, but not for many other body parts like the liver, pancreas, nose and heart. Could engineers design a car that grows itself this way, keeping everything symmetrical and in proportion as every part increases in size at different rates? We take this for granted as we watch a baby grow but it is a huge engineering challenge.

Similarities and Logic

Some limbs are used for walking, some for flying, some for swimming, and some for burrowing. Because of similar limb bones as illustrated at left, evolutionary biologists have been taught that all tetrapods have a common ancestor. This comparison has been used as both explanation for common ancestry and as evidence for common ancestry – a circular argument. ‘The common ancestor evolved a particular bone arrangement that was inherited by all descendants on its evolutionary branch.’ How do you know that? ‘Because they all have the same bone arrangement.’ But do similarities prove relationship by evolutionary descent? See the cartoon in this article, and watch this video for flaws in the evolutionary logic. Some evolutionists—but not all—have noticed the logical fallacy.

If similarities were used consistently as evidence for common ancestry, some evolutionists might conclude that tetrapods are related to hexapods instead of fish, because they already had four limbs, and fish had none; the hexapod ancestor simply lost two of its limbs. But no, others would chime in: those are false similarities. We know because hexapods are on a different branch of the evolutionary tree. The circularity is hard to give up. Common design, the best alternative compatible with the similarities, has been ruled out of consideration by fiat. To be considered scientific, only naturalistic explanations are permitted. No intelligence allowed!

And so, because the tree of evolutionary relationships is already assumed, fish must have been the ancestor of tetrapods. Here comes the latest fish story: a fish without limbs gave birth to the high hurdler, the gymnast, the ballet dancer and the violinist — by mistake. One day a cell accidentally migrated to a fin, and the rest was history. Usain Bolt could not be far behind, given a few hundred million years of more accidents.

This is the fallacy of non-sequitur combined with the fallacy of extrapolation taken to an absurd degree. It sounds preposterous, but one can accept absurdities as long as they are imagined to be gradual.

Where Do Our Limbs Come From? (University of Colorado, 24 May 2023).

The first thing obvious in this version of the Darwin Fish story is that finding an evolutionary explanation for limbs, this “major evolutionary transition,” has been contentious for a long, long time.

“This has become a topic that comes with bit [sic] of controversy, but it’s really a very fundamental question in evolutionary biology: Where do our limbs come from?” says co-corresponding author Christian Mosimann, PhD, associate professor and Johnson Chair in the Department of Pediatrics, Section of Developmental Biology at CU School of Medicine.

That question – where do our limbs come from? – has been subject [sic] of debate for more than 100 years.

Readers can learn about the battle between the “gill arch hypothesis” and the “lateral fin fold hypothesis” if they want, but it doesn’t matter, because both are built on the circular reasoning fallacy of homology. All evolutionists attribute the grace of a ballet dancer or the strength of a weightlifter to some genetic quirk in the fins of a fish long, long ago. The details of the competing fallacious accounts don’t fix the fallacy.

“It is a highly active research topic because it’s been an intellectual challenge for such a long time,” Mosimann says. “Many big labs have studied the various aspects of how our limbs develop and have evolved.” Among those labs are Dr. Mosimann’s colleagues and co-authors, Tom Carney, PhD, and his team at the Lee Kong Chian School of Medicine at Nanyang Technological University in Singapore.

Can the study of similarities be useful? Of course. Engineers and historians can learn from studying the “evolution” (in this case, design-guided thinking) of steering wheels, engines and electrical systems in cars since the late 1800s till now. Comparing limbs, cells, and genes in animals can also lead to profitable insights about their similarities and differences. Much of cancer research utilizes mouse models. It’s only when tetrapod limbs are explained by Darwinian evolution (unguided variation and natural selection) and then used as evidence for evolution that the circular fallacy comes back to haunt the scientist.

Divination to the Rescue

Looking for the magic moment where a cell, by chance, decided to migrate into position for the first limb bud, the evolutionary biologists at CU went into their lab to perform divination on their pet zebrafish. ‘Zebrafish, O great spirit of Darwin, please show us the point of departure from fin to limb. And if you can, please bring peace to the competing hypotheses.’ The answer came back from the oracle: ‘Look at my fibroblasts.’

… Mosimann and his lab team observed how a peculiar cell type with features of connective tissue cells, so-called fibroblasts that share a developmental origin with the cardiovascular system, migrated into specific developing fins of the zebrafish. It turns out that these cells may support a connection between the competing theories of paired appendage evolution.

We always knew these cells were odd,” he says. “There were these fibroblast-looking cells that went into the so-called ventral fin, the fin at the belly of the developing zebrafish. Similar fibroblast cells didn’t crawl into any other fin except the pectoral fin, which are the equivalent of our arms. So we kept noticing these peculiar fibroblasts, and we could never make sense of what these were for many years.

Looking at the fibroblasts, they visualized arms emerging. Another grad student, in a trance, visualized a Dual Origin theory that might bring peace to the competing hypotheses. Then the ghost of Haeckel made a surprise appearance!

By observing the mechanisms of embryonic development and comparing the anatomy of existing species, research groups like Mosimann’s can develop theories on how embryonic structures may have evolved or have been modified over time.  

“The embryo has features that are still ancient remnants that they have not lost yet, which provides insight into how animals have evolved,” Mosimann says. “We can use the embryo to learn more about features that just persist today, allowing us to kind of travel back in time,” Mosimann says.

Bergman tells about the fall of Haeckel’s Recapitulation Theory and other frauds in the history of evolutionary “research.”

Ernst Haeckel would be pleased to see that his long-discredited Recapitulation Theory is still getting some respect. Evolutionists can witness the evolutionary history of life in the embryo after all!

“We see that the body has a fundamental, inherent propensity to form bilateral, two-sided structures. Our study provides a molecular and genetic puzzle piece to resolve how we came to have limbs. It adds to this 100-plus year discussion, but now we have molecular insights.

The body has a propensity to form symmetrical limbs, you see. That explains them. Yes, and opioids induce sleep, the comic playwright Molière wrote, because they have a dormitive virtue. [Didn’t that kind of explanation go out with Aristotle?]

Answers? No. End of controversy? No. Understanding? No, but the divination exercise brought some “molecular insights” that might lead to it some day.

For all the considerable work and significance of the study, the Mosimann team recognizes that it is a key step, but not the end of the journey in the debate about paired appendages.

“I wouldn’t say we’ve solved the question, or even disproven either existing theory,” says Lalonde. “Rather, we’ve contributed meaningful data towards answering a major evolutionary question.”

Divination is hard work, they tell the dean. Hey, at least we got our fish story published in Nature. Keep the funding coming, and some day the coveted prize—Understanding—will come. Take our promissory note. It’s good for perpetuity.

What a fish story! This is hilarious that they would fall back on Aristotle, Molière and Haeckel in one swell Poof Spoof. But we can’t tell them because they are protected behind the one-way glass and sound-proof barrier that only lets them hear supportive voices from the Darwin Echo Chamber. It is very effective at filtering out laughter.

It’s not just hilarious, though, but sad. From their offices and labs in the academic halls of CU, after work they walked to their engineered cars and used their symmetrical arms to steer their bodies down the street, then walked into their homes and used their hands to eat dinner, not thinking about every breath they took through paper-thin alveoli in their lungs that brought oxygen to the hemoglobin in their blood, that nourished every cell with mitochondria gently ushering every toxic oxygen molecule to extract ions to drive their ATP synthase rotary engines, to power their taste buds and olfactory organs with the pleasant sensations of life.

It all just happened, they believe. There’s nobody to thank for all this exquisite bioengineering. The body has a propensity to form bilateral, two-sided structures like themselves. Stuff Happens.

Darwinism has a dormitive virtue, too; or rather, a dormitive vice.

 

 

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