Peppered Moths–Fraud or Textbook Case for Evolution–Face The Test

(Photo: Ben Sale/Flickr)

by Richard Conniff/Takepart.com

The peppered moth has long been one of the most popular stories in all of evolution—for Darwinians and creationists alike. The Darwinians have always treated the sudden appearance in the mid-nineteenth century of a dark-winged variety of this moth species (Biston betularia) as the first evidence of evolution taking place within a single human lifetime. Creationists have countered that this supposed slam-dunk for natural selection was instead just a product of biased scientific research, bordering on fraud.

A new study being published this week in the journal Nature finally resolves this often-bitter debate with irrefutable genetic evidence. So which side wins? Is it the textbook case for Darwinism? Or was it all a terrible mistake, as the creationists have alleged? I’m going to make you hold your breath for a bit while I fill in the background.

Until the mid-nineteenth century, the common form of peppered moth had a pale coloration suited to hiding on the bark of light-colored or lichen-coated tree trunks. The theory was that this camouflage enabled it to avoid being eaten by birds. But in 1848, in the English industrial city of Manchester, a specimen with black wings turned up, and by the end of the nineteenth century, this version of the peppered moth was everywhere. The paler, mottled version disappeared, almost becoming extinct.

The sudden shift was no accident, according to scientists. Reliance on coal for heating and industrial production in the nineteenth century blackened skies and forests. An editorial in the same issue of Nature quotes an 1851 railroad guide to the English industrial midlands: “The pleasant green of pastures is almost unknown, the streams, in which no fishes swim, are black and unwholesome … the few trees are stunted and blasted.” Pale moths could no longer hide against blackened tree trunks, and birds presumably devoured them. But the random appearance of the black form of the same species conferred a distinct advantage, because those moths were much harder for hungry birds to spot. It was natural selection in action.

(Incidentally, the same shift occurred in the same species at about the same time in the United States, particularly around

Science & The Rise of the American University–The Patriarch Conclusion

James Dwight Dana, 1857

Continued from “Spreading the Word about Science”:

The line dividing science and theology was, however, still practically nonexistent, and in this somewhat delicate context, James Dwight Dana was undoubtedly the most important of Silliman’s disciples. He was both a deeply religious man and the greatest American geologist of the nineteenth century, and much as Silliman had done for Timothy Dwight, he made it possible to expand the role of science without seeming overly threatening to religion or the humanities. Dana also explicitly took up Silliman’s mission of using the sciences to build Yale into a university.

In 1856, Dana gave a speech to Yale alumni lamenting those “who still look with distrustful eyes on science.” They seem, he said, “to see a monster swelling up before them which they cannot define, and hope may yet fade away as a dissolving mist.” That specter was twofold: the shadow cast by geology on the Genesis account of the Earth’s history, and the idea of evolution, which was already in the air. (Among other developments, a former student of Silliman’s named Thomas Staughton Savage, a missionary, had recently brought home from Africa the bones of an unknown primate with a disturbing resemblance to humans—the gorilla.) But Dana was deeply committed to a biblical view of creation, and he assured his listeners of the evidence provided by geology “that God’s hand, omnipotent and bearing a profusion of bounties, has again and again been outstretched over the earth; that no senseless development principle evolved the beasts of the field out of monads”—that is, unicellular organisms—“and men out of monkeys, but that all can alike claim parentage in the Infinite Author.” (Silliman shared this belief. In one of his last lectures he had declared, “Young men, those people may think as they please but for my part I shall never believe or teach that I am descended from a tadpole!”)

Having dismissed the evolutionary bugaboo, Dana went on to argue for

Unlocking the Secrets of the Polar Bear’s Amazing Evolution

(Photo: Ariadne Van Zandbergen/Getty Images)

We are a self-centered species, and what follows will seem at first like a particularly blatant example of it: Take polar bears, a species we seem to be pushing rapidly toward extinction, and study them—quick, before it’s too late—to learn how their biological adaptations can help us cope with our own deep-fried, high-fat modern diet.

“For polar bears, profound obesity is a benign state,” said one researcher, in the press release for a new study being published today in the journal Cell. “We wanted to understand how they are able to cope with that,” added another. “If we learn a bit about the genes that allow them to deal with that, perhaps that will give us tools to modulate human physiology down the line.”

Wow, and could I please have a side of bacon with that?

OK, I think the press release was pandering (starting with the headline “Humans May Benefit …”). The scientists, possibly nudged along by the news office, were just succumbing to the myth that most people will care about the study of other species only to the extent that it might somehow make their own lives more comfortable. Let’s be honest, though, polar bears are amazing all by themselves, and that’s what this new research is really all about.

What interested the scientists was the chance to learn how polar bears have adapted to live all winter in some of the coldest and least hospitable conditions on Earth, without access to drinking water, subsisting almost entirely on a heart-attack diet of seal blubber, and yet also swimming ultramarathon distances in summer.

“How is that even possible?” said Eline Lorenzen in an interview.

Dogs Have Evolved to Be With Us Even In Thin Air

Last month I posted a story about studies demonstrating that both Tibetans and Sherpas, the celebrated Himalayan climbers, have evolved a special set of adaptations to their high-altitude way of life.

From my point of view, that explained why I am such a high country wuss. Damn you, EPAS1!

Now it turns out their dogs have me beat, too.

Here’s the press release:

As humans have expanded into new environments and civilizations, man’s best friend, dogs, have been faithful companions at their sides. Now, with DNA sequencing technology readily available to examine the dog genome, scientists are gaining new insights into canine evolution.

In a new study published in the journal Molecular Biology and Evolution, author Dong-Dong Wu, et. al., explored the genetic basis of high-altitude adaptation of Tibetan Mastiffs, which were originally domesticated from the Chinese native dogs of the plains.

The authors examined genome-wide mutations (called single nucleotide polymorphisms, or SNPs) of 32 Tibetan Mastiffs, and compared them to 20 Chinese native dogs and 14 grey wolves. Overall, they identified more than 120,000 SNPs, and in their analysis, narrowed these down to 16 genes that have undergone positive selection in mastiffs, with 12 of these relevant to high altitude adaption.

These candidate genes have been shown to be