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Macroevolution by Loss: Flightless Birds Grounded by “Relaxed Selection”

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flightless cormorant

Evolutionists wanting to make a big deal out of flightlessness in birds are like the merchant who lost money on every sale but tried to make it up in volume.

Watch any documentary about Darwin, and you’re certain to get scenes of animals on the Galápagos Islands. In the panorama of unique creatures, you’re likely to see the flightless cormorant with its pitifully shrunken wings. Darwin made up a story about how this might have been good for the birds, but surely they’d rather fly like all other cormorants. Now for the first time, researchers have now tried to determine what happened genetically…and here’s the reason: they’re sick with a genetic disease.

With the help of a Chilean local expert, eight American scientists looked into the genome of the flightless cormorant, Phalacrocorax harrisi, and compared it with its flying relatives. It’s surprising that since Darwin’s time nobody had a clue what caused the change in this icon of evolution. The Introduction to the paper in Science Magazine states:

Changes in the size and proportion of limbs and other structures have played a key role in the evolution of species. One common class of limb modification is recurrent wing reduction and loss of flight in birds. Indeed, Darwin used the occurrence of flightless birds as an argument in favor of his theory of natural selection. Loss of flight has evolved repeatedly and is found among 26 families of birds in 17 different orders. Despite the frequency of these modifications, we have a limited understanding of their underpinnings at the genetic and molecular levels. [Emphasis added.]

Well, it’s about time to check Darwin on his speculative idea. Phys.org introduces the hero:

The flightless cormorant is one of a diverse array of animals that live on the Galapagos Islands, which piqued Charles Darwin’s scientific curiosity in the 1830s. He hypothesized that altered evolutionary pressures may have contributed to the loss of the ability to fly in birds like the Galapagos cormorant.

We see the Darwinian escape valve at work again. It’s crystalized in those two words, “may have.” Anything may have happened. Pigs may have flown millions of years ago, when nobody could observe them. As luck would have it, they didn’t leave any fossils. But altered evolutionary selection pressures “may have” contributed to pigs’ loss of ability to fly.

To Darwinians, “evolutionary pressure” can point in any direction: up, down, or sideways. But think again. Some forces, like gravity, point only down. Suppose we suggested that gravity can point in any direction: sometimes making pigs fly. That would be ridiculous. Darwin needs to prove that selection pressure can point up toward innovation and progress; he can’t merely assume it. But we’ll take him up on this example of negative selection. Sure, evolution can break things, and it did so in the case of flightless cormorants.

Phys.org explains what broke:

The team also found that the flightless cormorants have an abnormally high number of genetic mutations affecting cilia — small, hair-like structures that protrude from cells and regulate everything from normal development to reproduction.

Cilia play a critical role in bone growth. People born with skeletal ciliopathies have shorter limbs, narrowed chests and stunted rib cages — as do the Galapagos cormorants. The UCLA results suggest that CUX1 controls many aspects of cilia, some of which influence bone growth.

These birds are sick. They continue to breed because the genetic sickness has spread to the whole colony, and there’s nobody else to breed with. They have what’s called ciliopathy, or a genetic disease that hinders the healthy development of cilia. Cilia, remember, are examples of irreducible complexity that Michael Behe described in his book, Darwin’s Black Box. Almost all cells have these molecular machines; some are motile, like those that sweep dust out of the airways, but many are stationary, acting like antennae. A lack of healthy cilia, when not fatal, leads to numerous genetic diseases. One feels sorry for these poor birds, but good icons of evolution they are not.

Some evolutionists try to rescue Darwin in this case by suggesting that the genetic disease helps the birds in some way: “changes that lead to flightlessness may help birds survive because they enhance their ability to do something else, like swimming — so-called positive selection.” Nice try, but more likely, selection pressure for costly flight and wings was “relaxed” because of a lack of predators on the island. “When flying isn’t essential for survival, the mutations that hinder flight can gradually accumulate in the gene pool.” Lives there a Darwinist who would consider this a helpful argument for universal common descent by mutation and selection?

“Relaxed selection” is like relaxed maintenance on your car. Without upkeep, it will rust and parts will break. You still may be able to drive it a little, but relaxation is not going to build a better car, or build a car in the first place.

The researchers found a way to manipulate the genetic data to affirm that 3 out of 11 genes showed evidence of “positive selection toward flightlessness.” They do this not by measuring actual benefits to the bird, but just measuring the ratio of synonymous to non-synonymous mutations. “These results suggest that selection toward flightlessness may be partially responsible for the phenotype of P. harrisi.” The results “suggest” that it “may” be “partially” responsible. Let’s try that on our relaxed-maintenance automobile: “The results suggest that positive selection toward rust may have been responsible for the car’s inability to drive faster than 20 mph.” Hooray! Evolution confirmed!

In a last-ditch effort to rescue Darwin, the research team suggested that the birds are stuck in a Peter-Pan-like juvenile stage, a condition called “heterochrony” (“other-timing”). Scientific jargon loses some of its power to impress when you translate it out of Latin. They also dazzle with “paedomorphosis” — “baby shape” (pedo as in pediatrician, morph for shape or form). Translation: “other-timing” led to “baby-shape.” Question: What, exactly, does that explain, other than to conceal the observation in a language most people don’t understand? And what does it have to do with Darwinian evolution?

Although we have identified multiple variants that likely contribute to the flightless phenotype of P. harrisi, we cannot exclude the possibility that other genes and pathways may contribute to the phenotype, nor the contribution of noncoding regulatory variants. Further characterization of the individual and joint contributions of the variants found in this study will help us to reconstruct the chain of events leading to flightlessness and to genetically dissect macroevolutionary change. We hypothesize that mutations in cilia or functionally related genes could be responsible for limb and other skeletal heterochronic transformations in birds and diverse organisms, including humans.

All is not in vain. At least we now know a little bit about genetic variants in flightless cormorants compared to flying cormorants. That’s interesting. We’ve learned part of what broke to make the birds genetically sick and grounded. But if there was any macroevolution happening, it was downwards, from the skies to the dirt, from working cilia to broken cilia. If there was a transformation, it was from powered flight to pitiful flopping.

It’s a loss every way you look at it. But don’t worry; Darwin will make it up in volume!

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Evolution News & Science Today (EN) provides original reporting and analysis about evolution, neuroscience, bioethics, intelligent design and other science-related issues, including breaking news about scientific research. It also covers the impact of science on culture and conflicts over free speech and academic freedom in science. Finally, it fact-checks and critiques media coverage of scientific issues.



ciliacormorantDarwin's Black BoxflightlessnessGalápagos IslandsMichael BehePhalacrocorax harrisiUCLA