"Instant" Evolution Seen in Darwin's Finches, Study Says #4

"Instant" Evolution Seen in Darwin's Finches, Study Says, National Geographic, Mason Inman, July 14, 2006

[Graphic: The Galapagos finch family tree (click here to enlarge): Dr George Johnson. Continued from part #3.]

The Galápagos Islands' 14 species of finches [As previously quoted, Peter Grant himself acknowledged that there may be only six (or even less) species of finches on the Galapagos, because "if species were strictly defined by inability to interbreed" (which is the usual Biological Species Concept definition of species) "then ... At the extreme, six species would be recognized in place of the current 14, and additional study might necessitate yet further reduction":

"Writing in Science in 1992, the Grants noted that the superior fitness of hybrids among populations of Darwin's finches `calls into question their designation as species.' [Grant P.R. & Grant B.R, `Hybridization of Bird Species,' Science, Vol. 256, 1992, pp. 193-197] The following year, Peter Grant acknowledged that if species were strictly defined by inability to interbreed then `we would recognize only two species of Darwin's finch on Daphne,' instead of the usual four [Grant P.R., "Hybridization of Darwin's finches on Isla Daphne Major, Galapagos," Philosophical Transactions of the Royal Society of London B, Vol. 340, 1993, pp.127-139]. `The three populations of ground finches on Genovesa would similarly be reduced to one species,' Grant continued. `At the extreme, six species would be recognized in place of the current 14, and additional study might necessitate yet further reduction." (Wells, J., "Icons of Evolution: Science or Myth?: Why Much of What We Teach About Evolution is Wrong," Regnery: Washington DC, 2000, pp.172, 312n) ]

all evolved from one ancestral species, which arrived from the South American mainland about two to three million years ago. [Note that these finches have had "two to three million years" for natural selection to do its stuff, yet these finches are still finches! Since the ancestor(s) of these finches "arrived from the South American mainland," which is an unbroken stretch of ocean ~570 miles (~900 kms) away, presumably these finches have no great difficulty flying between the islands, which Darwin noted in his Origin of Species were "situated within sight of each other."

So the scenario that the Grants are reporting of the large ground finch (Geospiza magnirostris) arriving on Daphne Major island and competing with the medium ground finch (Geospiza fortis) for the larger seeds, presumably must have happened many thousands of times in the past "two to three million years"!

Therefore, the most reasonable assumption is that these finches completed their adaptive radiation into the various ecological niches open to them comparatively soon after their ancestor(s) arrived "two to three million years ago" and thereafter they have been in stasis.

If so, then far from demonstrating the power of natural selection, they are in fact demonstrating its limitations, and far from Finch Beaks Say Darwin Was Right, they are in fact showing that Darwin was wrong in his assumption that there was "no limit to this power" of natural selection:

"... there seems at first sight no limit to the amount of profitable diversification of structure, and therefore no limit to the number of species which might be produced" by "the continued action of natural selection" (Darwin C.R., "The Origin of Species," Sixth Edition, 1872, Senate: London, 1994, reprint, p.101)

"If man can by patience select variations useful to him, why, under changing and complex conditions of life, should not variations useful to nature's living products often arise, and be preserved or selected? What limit can be put to this power, acting during long ages and rigidly scrutinising the whole constitution, structure, and habits of each creature,-favouring the good and rejecting the bad? I can see no limit to this power, in slowly and beautifully adapting each form to the most complex relations of life. The theory of natural selection, even if we look no farther than this, seems to be in the highest degree probable." (Darwin, 1872, p.412)]

That original species branched out into many others, with each one specialized for different roles. [That's right. And once the finches had "branched out" and had become "specialized for different roles," that was that!]

The woodpecker finch, for example, has evolved to the point where it can drill holes in trees, while the vampire finch drinks other birds' blood [There again is the Fallacy of Equivocation on the word "evolution" (i.e. its cognate "evolved"). All these finches have done is adapt their behaviour (not their bodies or their species) to various ecological niches open to them.

Of the "woodpecker finch," Wikipedia says that "Tool use, however, is not a common behavior; most prey items are extracted using the beak in the usual manner." And of the "vampire finch," Wikipedia says it "feeds primarily on the blood of the Nazca Booby and Blue-footed Booby, pecking at the boobies' skin with their sharp beaks until blood is drawn" and "It is theorized that this behavior evolved from the pecking behavior that the finch used to clean parasitesfrom the plumage of the booby."

Hardly "evolution" unless, as I pointed out in the previous post, one defines "evolution" so broadly that it cannot be false. But then it is not falsifiable, and hence not science.]

Continued in part #5.

Stephen E. Jones, BSc (Biol).
`Evolution Quotes Book'