But Is it Evolution? 02/18/2011
Feb 18, 2011 — Scientists have been noticing some things that seem contrary to Darwin’s predictions – but they give Darwin credit anyway.
- Not till us: The chambered nautilus is a “living fossil,” that uses “jet propulsion,” New Scientist said, with origins way back in the Cambrian. Has its fitness improved over all that time? “Its movement is ungainly and slow, but it has survived virtually unchanged for at least 450 million years, so it must be doing something right,” reporter Michael Marshall remarked. “Its relatives the ammonoids dominated the oceans for millions of years before going extinct along with the dinosaurs 65 million years ago – but the nautilus came through that disaster and is still with us today,” despite having “much simpler brains than other cephalopods.” They also have weaker eyes and take longer to mature, and are currently endangered by overfishing. Wouldn’t evolution get rid of adaptations that are inferior? “Such jet power is a cumbersome way of getting around the seas, and most modern cephalopods have largely abandoned it,” Marshall explained in a personification of negative selection. “Despite its primitive way of getting around, however, the nautilus is no mental slouch.”
- Debunking neo-Darwinist genetics: According to neo-Darwinism, beneficial genetic mutations become established by “selective sweeps” in a population. “The selective sweep model was introduced in 1974 and has pretty much been the central model ever since,” Molly Przeworski [U of Chicago] said. In an article posted by PhysOrg. “It is fair to say that it is the model behind almost every scan for selection done to date, in humans or in other organisms.”
Unfortunately, the model doesn’t fit the DNA. Looking at the human genome in more detail, the article concluded, “The result suggests that classic selective sweeps could not have been the most common cause of these low diversity troughs, leaving the door open for other modes of evolution.” Unfortunately again, no other mode was provided:
“Phenotypic variation in humans isn’t as simple as we thought it would be,” [Ryan] Hernandez [UC San Francisco] said. “The idea that human adaptation might proceed by single changes at the amino acid level is quite a nice idea, and it’s great that we have a few concrete examples of where that occurred, but it’s too simplistic a view”....
Przeworski said... “These findings call into question how much more there is to find using the selective sweep approach, and should also make us skeptical of how many of the findings to date will turn out to be validated.”
- Mystery of Mysteries: What was Darwin’s “mystery of mysteries?” Believe it or not, it was the thing his famous book set out to explain. “Although Charles Darwin titled his book On the Origin of Species, speciation was one thing he could not explain,” wrote Bob Holmes in New Scientist. “He called it the ‘mystery of mysteries’, and even a century-and-a-half later the mechanism by which two groups of animals become genetically incompatible remains one of the greatest puzzles in biology.” That is a surprising statement, because in popular understanding, it was Darwin’s mechanism of natural selection that promoted evolution into a scientific theory over earlier speculations about common ancestry.
Holmes went on to describe suggestions that a “speciation gene” named Prdm9 might be “evolution’s missing X factor” to solve the mystery. It’s a rapidly evolving gene, he claimed – a virtual “evolutionary sprinter” on the basis of sequence dissimilarities between humans and chimpanzees. After a convoluted tale about how this gene blinks on and off, and incompatible mutants make mice sterile, he proposed an “intriguing idea” that “Variation in this gene could be driving a wedge between different parts of our human population.” But alas, “the evidence to date seems not to corroborate it.” Evidence, however, should never be allowed to get in the way of a good story. One expert he quoted said, “We can speculate that this could be some sort of universal reproductive-isolation gene in animals, which would be beautiful,” but, alas again, we shall have to wait, after waiting 150 years already since Darwin, to find out “If that turns out to be the case”.
- Feathery evolution: Ken Dial, the Montana man one who watches the partridge family run up ramps (12/22/2003), got notoriety again in National Geographic’s story on the evolution of feathers. Writer Carl Zimmer could never quite figure out if feathers arose for sexual display, or for insulation, or for flight, but they evolved somehow, he is sure. Dinosaurs with imaginary feathers also made the final cut of the Darwinian script. “The origin of this wonderful mechanism is one of evolution’s most durable mysteries,” Zimmer said. Whatever happened, or why, “there is one natural wonder that just about all of us can see, simply by stepping outside,” he teased: “dinosaurs using their feathers to fly.” From there he went on to describe the marvelous design of feathers:
Airplane wings exploit some of the same aerodynamic tricks. But a bird wing is vastly more sophisticated than anything composed of sheet metal and rivets. From a central feather shaft extends a series of slender barbs, each sprouting smaller barbules, like branches from a bough, lined with tiny hooks. When these grasp on to the hooklets of neighboring barbules, they create a structural network that’s featherlight but remarkably strong. When a bird preens its feathers to clean them, the barbs effortlessly separate, then slip back into place.Most people believe airplane wings came from intelligent design, but all Zimmer could propose for the origin of those “vastly more sophisticated” feathers from simple scales were suggestive analogies. “The long, hollow filaments on theropods posed a puzzle,” he said of the barbs on some dinosaur skins that lack the complex interlocking structures of flight feathers. “If they were early feathers, how had they evolved from flat scales? Fortunately, there are theropods with threadlike feathers alive today: baby birds.” He then said that reptiles and birds both have tiny patches in their skins called placodes that produce bristles. Did reptile placodes evolve into feathers via a “simple switch in the wiring of the genetic commands inside placodes”? If so, “Once the first filaments had evolved, only minor modifications would have been required to produce increasingly elaborate feathers.”
Obviously. Stuff happens all the time in evolution. Voila, said the viola: “In other words, feathers were not merely a variation on a theme: They were using the same genetic instruments to play a whole new kind of music.” Unmixing of metaphors is left as an exercise. Complete that exercise before tackling the more difficult assignment: understanding the evolutionary significance of another of Zimmer’s evidence-challenged plot lines: “So perhaps the question to ask, say some scientists, is not how birds got their feathers, but how alligators lost theirs.” (Caution: do NOT visualize a magic dragon.) It would seem that if the ancestor of all these animals already had feathers, the origin of feathers has just been pushed back into the unknown. Ken Dial’s partridge family (05/01/2006, 01/25/2008) got the final exit pun, complete with an apparition of Haeckel’s friendly ghost: “Perhaps, says Dial, the path the chick takes in development retraces the one its lineage followed in evolution—winging it, so to speak, until it finally took wing.” So to speak.
We could go on and on. This borders on the criminal. Taking data that falsifies evolution and using it to praise Charlie is like election fraud. Unlike Dawkins, though, we will not stoop to calling our opponents ignorant, stupid, insane, or wicked – just deceived. So deceived, in fact, that they cannot even receive the sight to conceive their own deception. The only remedy for the self-deceived is truth given with tough love.Young’s Law confirmed
Next headline on: Marine Biology • Birds • Genetics • Darwin and Evolution • Dumb Ideas
By accident, researchers at UCLA seem to have found a cure for baldness, at least in mice (PhysOrg). Now they are seeking funding to study it further. See Young’s Law, right sidebar.
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