Darwin's Finches: What Evolved, the Birds or the Story?
Imagine spending 40 years of your life promoting Darwinian evolution with Galapagos finches, only to find out on Darwin Day that the birds hybridize and cross-breed.
It’s Darwin Day, in case anyone noticed. Charles Darwin’s birthday hasn’t quite become the global holiday some of his ardent devotees have wished. (It’s also Abraham Lincoln’s birthday in America.) What better way to remember Darwin than with a fresh look at his iconic finches from the Galapagos Islands?
A new paper came out in Nature about Darwin’s finches, suspiciously timed for Darwin Day. It describes genome comparisons of 120 individual birds from various Galapagos islands and the mainland, comprising 15 species of finches. The results are hardly supportive of Darwin’s main theory of biological innovation by an unguided mechanism (more on that in a bit), but the mere mention of Darwin+finch is bound to give the reporters a high:
- DNA Reveals How Darwin’s Finches Evolved (National Geographic)
- Evolution of Darwin’s finches and their beaks (Science Daily)
- A gene that shaped the evolution of Darwin’s finches (Princeton press release)
- Genomes of Darwin’s finches may explain the shape of human faces (Science Magazine)
The BBC News was slightly less celebratory with its headline, “Genomes reveal Darwin finches’ messy family tree.” Messy it is. Contrary to Darwin’s picture of speciation from a common ancestor, the genome data shows a lot of crossbreeding between the supposedly-separate species.
The study also revealed a surprisingly large amount of “gene flow” between the branches of the family.
This indicates that the species have continued to interbreed or hybridise, after diversifying when they first arrived on the islands.
The researchers looked for genetic bases for diversification, and honed in on one gene named ALX1 that appears to be implicated in beak changes. It’s not completely responsible, the articles point out; it’s just one gene of several involved in beak formation. In humans, mutations to this gene are implicated in facial deformations such as cleft palate. It’s not giving humans any evolutionary advantage, in other words.
Some scientists were surprised to find so much gene mixing. The BBC article continues:
Other geneticists have expressed mixed reactions to the results. Dr Julia Day, from University College London, was impressed by the level of mixing reported between the finch species – which she said are “a textbook example of radiation“.
She told the BBC: “The fact that they’re finding this hybridisation going on – this genetic mixing – it’s quite a seminal finding.
“When you look at their results, you can see the trees are quite messy, in terms of the traditional species groupings.”
Another was not surprised. The birds have wings, after all, and can fly between the islands. None of the articles mentioned that creationists are not surprised, either. They allow for variations in beak size and feather coloration, just like they see wide variations in dogs and cats. They just point out that the finches are still finches: beaks, wings, eyes and all. Nothing new, requiring new genetic information, has evolved. In fact, the variability in beaks is more pronounced when the finches interbreed, restoring the inherent variability in the ALX1 gene and other genes. This implies that some variants can become genetic dead ends; they lose genetic information.
In short, nothing about Darwin’s finches distinguishes Darwinian evolution from young-earth creationism. Creationists are fully comfortable with “horizontal” genetic changes that do not add new information. The information for building beaks, eyes and wings are all present in each of these varieties.
Most of the articles re-tell Darwin’s adventures on the Beagle, how he collected the finches, and used them to formulate his theory of natural selection. His theory of universal common ancestry, though, amounts to a huge extrapolation from limited data, and turns “horizontal” variation (as exemplified by animal breeders’ “artificial selection”) into “vertical” variation, for which there is no evidence.
The articles also give prominence to Peter and Rosemary Grant, the Princeton pair that has spent 40 years researching the finches (see photo on Princeton press release). They found that drought favored birds with stronger beaks, but the variants reverted to the mean when rainy seasons returned. Nature quotes Peter speculating about what Darwin would think of the new genetic data (after getting a crash course in genetics). “I think he might wish to redraw that tree by making connections between some of the branches, representing the hybridization and gene exchange.” All in all, Grant counts this a Darwinian success story. “But then he would be delighted. The results are entirely consistent with his ideas.”
What else could Mr. Grant say, after spending four decades trying to prove Darwin right? That it was all a waste of time?
For Darwin Day (Feb. 12), get a copy of Darwin Day in America by John West (see this video trailer). It will really open your eyes to the damage wrought by this one man’s terrible idea that all the beauty and variety of the living world could be explained by struggle for existence and the survival of the fittest due to random variations and unguided natural processes. His chant should be, “Darwin lied, millions died”. Make that 100 million. Now, 155 years later, to find out that Charlie’s “Exhibit A” for natural selection shows no gain in complexity, should seethe in your brain.
For earlier posts about the Grants, see 7/14/06, “Darwinism Confirmed! How? Finch Beaks Got Smaller!” and 1/05/11, “Never Say Die: Researchers Spend 37 Years Looking for Evolution in Darwins Finches.” Or, search on “Rosemary” in the search bar.
Nothing is ever a complete failure. It can always serve as a bad example.