<i>Wired Science</i>: One Long Bluff - Evolution News & Views

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Wired Science: One Long Bluff

According to a recent online report from Wired Science, "On one of the Galápagos islands whose finches shaped the theories of a young Charles Darwin, biologists have witnessed that elusive moment when a single species splits in two."

If it were true, this would be very important news. Evolutionary biologists have long recognized that Charles Darwin (despite the title of his most famous book) failed to solve what he called "the mystery of mysteries," -- the origin of species. Darwin argued that it happens by natural selection acting on small variations, but no one has ever observed the origin of a new species ("speciation") by this process. Evolutionary biologist Keith Stewart Thomson wrote in 1997 that "a matter of unfinished business for biologists is the identification of evolution's smoking gun," and "the smoking gun of evolution is speciation, not local adaptation and differentiation of populations." Before Darwin, the consensus was that species can vary only within certain limits; indeed, centuries of artificial selection had seemingly demonstrated such limits experimentally. "Darwin had to show that the limits could be broken," wrote Thomson, "so do we." 1

According to Wired Science, the mystery is now solved. "Evolution's smoking gun" has been found.

Or has it? Darwin called The Origin of Species "one long argument."2 Some of Darwin's modern followers have claimed to observe speciation by natural selection, but the evidence doesn't support their claim. In The Politically Incorrect Guide to Darwinism and Intelligent Design 3 I called it "one long bluff," and the report in Wired Science is part of the bluff.

Forget the fact that the Galápagos finches did not shape "the theories of a young Charles Darwin." On the voyage of the Beagle Darwin collected nine of the islands' thirteen species, but he identified only six of them as finches. Except in two cases, Darwin failed to observe any differences in the birds' diets, and even then he failed to correlate diet with beak shape. Only after the Beagle returned to England did ornithologist John Gould begin to sort out the birds' relationships, and much of the information Darwin provided turned out to be wrong. He never even mentioned the finches in The Origin of Species, and they were not named "Darwin's finches" until 1936. As for the claim that they impressed Darwin as evidence of evolution, historian of science Frank Sulloway wrote in the 1980s, "nothing could be further from the truth." 4 5

The deeper problem with the Wired Science report is not its perpetuation of the legend of Darwin's finches, but its false claim that biologists have now "witnessed that elusive moment when a single species splits in two." This is not what Peter and Rosemary Grant reported in their scientific article in the Proceedings of the National Academy of Sciences. 6

According to the Grants, in 1981 they found an unusually large male medium ground finch (scientific name: G. fortis) on the island of Daphne Major that they labeled 5110. They inferred that it had probably immigrated from the nearby island of Santa Cruz--though they could not be certain. For 28 years, the Grants followed all known descendants of this presumed immigrant, and genetic analysis suggested that after 2002 the descendants of 5110 bred only with each other (and were thus "endogamous"). The inbred group had a distinctive song that may have contributed to its reproductive isolation from other medium ground finches that were in the same area ("sympatric").

But the Grants did not go so far as to label the inbred descendants a new species. "We treat the endogamous group as an incipient species because it has been reproductively isolated from sympatric G. fortis for three generations and possibly longer." But an "incipient species" is not the same as a new species. In The Origin of Species, Darwin wrote: "According to my view, varieties are species in the process of formation, or are, as I have called them, incipient species." 7 But how can we possibly know whether two varieties (or races) are in the process of becoming separate species? Saint Bernards and Chihuahuas are two varieties that cannot interbreed naturally. The Ainu people of northern Japan and the !Kung of southern Africa are separated not only geographically, linguistically, and culturally, but also (for all practical purposes) reproductively. Are dog breeds and human races therefore "incipient species?"

There's no way we can know, unless we observe varieties becoming separate species at a future date. Designating two reproductively isolated populations "incipient species" is nothing more than a prediction that speciation will eventually occur. It is a far cry from observing the origin of a new species.

Indeed, in their scientific article the Grants acknowledge that "many episodes of incipient speciation probably fail for every one that succeeds." In the present case, "it is too early to tell whether reproductive isolation is transitory or is likely to be enduring. The odds would seem to be against long-term persistence of the immigrant lineage as a reproductively isolated population." Among other things, it could go extinct due to inbreeding or an environmental catastrophe. Or it "might disappear through interbreeding with other G. fortis."

Interbreeding among supposedly reproductively isolated species of Galápagos finches is nothing new. The Grants themselves reported widespread hybridization among those species in the 1990s.8 9 This is one reason why, according to a November 16 report in the journal Nature, "the Grants aren't yet ready to call 5110's lineage a new species." Indeed, "the Grants think there is only a small chance that 5110's descendants will remain isolated long enough to speciate." 10

So, will the inbred population described by the Grants become a new species? Maybe; maybe not. Does the Grants' work explain how different species of finches descended with modification from a common ancestor? Maybe; maybe not. Does the report in Wired Science mean that "biologists have witnessed that elusive moment when a single species splits in two?" Absolutely not.

By the way, none of this has anything to do with ID, which asserts only that some features of living things are better explained by an intelligent cause than by unguided processes. The splitting of one species into two species that are very similar to each other (as the Galápagos finches are) could happen without design. No, the issue is honesty in science reporting, and whether -- when it comes to the central claim in Darwin's theory, from which all else follows -- modern Darwinists have anything better to offer than one long bluff.

References:
1 Keith Stewart Thomson, "Natural Selection and Evolution's Smoking Gun," American Scientist 85 (1997): 516-518.

2 Charles Darwin, On the Origin of Species (London: John Murray, 1859), p. 459.

3 Jonathan Wells, The Politically Incorrect Guide to Darwinism and Intelligent Design (Washington, DC: Regnery Publishing, 2006).

4 Frank J. Sulloway, "Darwin and His Finches: The Evolution of a Legend," Journal of the History of Biology 15 (1982): 1-53.

5 Frank J. Sulloway, "Darwin and the Galápagos," Biological Journal of the Linnean Society 21 (1984): 29-59.

6 Peter R. Grant & B. Rosemary Grant, "The secondary contact phase of allopatric speciation in Darwin's finches," Proceedings of the National Academy of Sciences USA (published online before print November 16, 2009).

7 Charles Darwin, The Origin of Species (London: John Murray, 1859), p. 111.

8 B. Rosemary Grant & Peter R. Grant, "Evolution of Darwin's finches caused by a rare climatic event," Proceedings of the Royal Society of London B 251 (1993): 111-117.

9 Peter R. Grant & B. Rosemary Grant, "Hybridization of Bird Species," Science 256 (1992): 193-197.

10 Daniel Cressey, "Darwin's finches tracked to reveal evolution in action: A new species of finch may have arisen in the Galapagos," Nature (published online November 16, 2009).


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