Thursday, July 27, 2006

"Instant" Evolution Seen in Darwin's Finches, Study Says #5

"Instant" Evolution Seen in Darwin's Finches, Study Says, National Geographic, Mason Inman, July 14, 2006 ... [Continued from part #4. Graphic: Woodcut of Galapagos finches included by Darwin in the 1845 Second Edition of his "Journal of Researches" (later "Voyage of the Beagle"). See below.]

.... Ironically, naturalist Charles Darwin missed signs of evolution among these finches during his 1831 visit to the Galápagos. Only later, with the help of other collectors and scientists, was he able to see how evolution was responsible for the variety of finches. [This is an important point. That it still has to be written ~ 175 years after the event, to correct the legend in the public mind that Darwin (in my opinion dishonestly and deliberately) created by rewriting history in his "Journal of Researches" (1839, 1845) (which after his death was abridged and republished in 1905 as "The Voyage of the Beagle"), to make it sound like it was while he was at the Galapagos Islands he saw the grades of beaks of its finches from different islands and that was what converted him from a Bible-believing creationist into an evolutionist.

But in fact, in Darwin's daily diary, he only mentioned the finches once and that very briefly, i.e. "It was however sufficient to draw together all the little birds in the country; Doves & Finches swarmed round its margin":

"(October 1st.) Albemarle Island is as it were the mainland of the Archipelago; it is about 75 miles long & several broad; is composed of 6 or 7 great Volcanic Mounds from 2 to 3000 ft. high, joined by low land formed of Lava & other Volcanic substances. Since leaving the last Island, owing to the small quantity of water on board, only half allowance of water has been served out (i.e. ½ a Gallon for cooking & all purposes). This under the line with a Vertical sun is a sad drawback to the few comforts which a Ship possesses. From different accounts, we had hoped to have found water here. To our disappointment the little pits in the Sandstone contained scarcely a Gallon & that not good. It was however sufficient to draw together all the little birds in the country; Doves & Finches swarmed round its margin. I was reminded of the manner in which I saw at Charles Isd a boy procuring dinner for his family. Sitting by the side of a Well, with a long stick in his hand, as the doves came to drink he killed as many as he wanted & in half an hour collected them together & carried them to the house. To the South of the Cove I found a most beautiful Crater, elliptic in form, less than a mile in its longer axis & about 500 feet deep. Its bottom was occupied by a lake, out of which a tiny Crater formed an Island. The day was overpoweringly hot; & the lake looked blue & clear. I hurried down the cindery side, choked with dust, to my disgust on tasting the water found it Salt as brine. This crater & some other neighbouring ones have only poured forth mud or Sandstone containing fragments of Volcanic rocks; but from the mountain behind, great bare streams have flowed, sometimes from the summit, or from small Craters on the side, expanding in their descent, have at the base formed plains of Lava. The little of the country I have yet seen in this vicinity is more arid & sterile than in the other Islands. We here have another large Reptile in great numbers; it is a great Lizard, from 10-15 lb. in weight & 2-4 feet in length; is in structure closely allied to those "imps of darkness" which frequent the sea-shore. This one inhabits burrows to which it hurries when frightened, with quick & clumsy gait. They have a ridge & spines along the back; are colored an orange yellow, with the hinder part of back brick red. They are hideous animals; but are considered good food: this day forty were collected." " (Darwin, C.R., "Charles Darwin's Diary of the Voyage of HMS Beagle," Barlow, N., ed., Cambridge University Press: Cambridge, 1933, p.338)

Darwin arrived back in England in 1836 and later found in 1837 (i.e. ~2 years after he was at the Galapagos) that the ornithologist John Gould had classified the finches as separate species.

Darwin's 1839 First Edition of his "Journal of Researches" (which the Penguin edition of "The Voyage of the Beagle" is), was a model of objectivity:

"In my collections from these islands, Mr Gould considers that there are twenty-six different species of land birds. ... A group of finches, of which Mr Gould considers there are thirteen species; and these he has distributed into four new sub-genera. These birds are the most singular of any in the archipelago. They all agree in many points; namely, in a peculiar structure of their bill, short tails, general form, and in their plumage. The females are gray or brown, but the old cocks jet-black. All the species, excepting two, feed in flocks on the ground, and have very similar habits. It is very remarkable that a nearly perfect gradation of structure in this one group can be traced in the form of the beak, from one exceeding in dimensions that of the largest gros-beak, to another differing but little from that of a warbler." (Darwin, C.R., "Voyage of the Beagle: Charles Darwin's Journal of Researches," [1839], Browne, J. & Neve, M., eds, Penguin: London, 1989, pp.275-276. Emphasis original)

But in his 1845 Second Edition (which is the one that was later popularised as "The Voyage of the Beagle") Darwin added, "Seeing this gradation and diversity of structure in one small, intimately related group of birds, one might really fancy that from an original paucity of birds in this archipelago, one species had been taken and modified for different ends" (my emphasis):

"The remaining land-birds form a most singular group of finches, related to each other in the structure bf their beaks, short tails, form of body, and plumage: there are thirteen species, which Mr. Gould has divided into four sub-groups. All these species are peculiar to this archipelago; and so is the whole group, with the exception of one species of the sub-group Cactornis, lately brought from Bow island, in the Low Archipelago. Of Cactornis, the two species may be often seen climbing about the flowers of the great cactus-trees; but all the other species of this group of finches, mingled together in flocks, feed on the dry and sterile ground of the lower districts. The males of all, or certainly of the greater number, are jet black; and the females (with perhaps one or two exceptions) are brown. The most curious fact is the perfect gradation in the size of the beaks in the different species of Geospiza, from one as large as that of a hawfinch to that of a chaffinch, and (if Mr. Gould is right in including his sub-group, Certhidea, in the main group), even to that of a warbler. The largest beak in the genus Geospiza is shown in Fig. 1, and the smallest in Fig. 3; but instead of there being only one intermediate species, with a beak of the size shown in Fig. 2, there are no less than six species with insensibly graduated beaks. The beak of the sub-group Certhidea, is shown in Fig. 4. The beak of Cactornis is somewhat like that of a starling; and that of the fourth sub-group, Camarhynchus, is slightly parrot-shaped. Seeing this gradation and diversity of structure in one small, intimately related group of birds, one might really fancy that from an original paucity of birds in this archipelago, one species had been taken and modified for different ends." (Darwin, C.R., "The Voyage of the 'Beagle'," [1845], Edito-Service: Geneva, n.d., reprint, pp.379-380)

which most people took as meaning that Darwin saw them at the Galapagos, and so "a considerable [false] legend in the history of science" was created, which was only was corrected in the 1980's by a science historian and later psychologist, Frank J. Sulloway:

"As Darwin remarked in the second edition of his Journal of Researches. `Seeing this gradation and diversity of structure in one small, intimately related group of birds, one might really fancy that from an original paucity of birds in this archipelago, one species had been taken and modified for different ends' (1845:380). ... In fact, over the years Darwin's finches have become the focus for a considerable legend in the history of science, one that ranks alongside other famous stories that celebrate the great triumphs of modern science. . It has frequently been asserted that Darwin's finches, along with certain other organisms from the Galapagos Archipelago, were what first alerted Darwin to the possibility that species might he mutable. But as David Lack (1949:9) has pointed out, Darwin did not even discuss the finches in the diary of his voyage on the Beagle- except for a single reference in passing, and his treatment of them in the first edition of his Journal of Researches (1839:461-462) was brief and matter of fact compared with the famous statement about them that he added to the 1845 edition. Given these facts, Lack concluded that Darwin's evolutionary understanding of the finches was largely retrospective. This interpretation is essentially correct, although Lack, who did not examine Darwin's unpublished scientific notes from the Beagle voyage, failed to appreciate the reasons for Darwin's gradual insight." (Sulloway, F.J., "Darwin and His Finches: The Evolution of a Legend," Journal of the History of Biology, Vol. 15, No. 1, 1982, pp.1-53, pp.3,5)

As ecologist James G. Sanderson summarising Sulloway's findings pointed out: 1) "the familiar story of `Darwin's finches' that many people learned in school is mostly just that-a story"; 2) "Darwin gathered few examples of these supposedly crucial birds"; 3) "He failed to recognize the importance of the specimens that he did collect and neglected to so much as tag each one with the name of the island from which it came"; 4) "Darwin did not even realize that some of these birds were finches until six years later; 5) "His original account says very little about the finches, reflecting the minimal attention he paid to these birds when he first saw them"; 6) "One reads gushing descriptions in The Voyage of the Beagle only because Darwin revised the text of his journal in 1845 to reflect what he had pieced together in the intervening years":

"Tradition holds that Charles Darwin glimpsed the signature of natural selection quite early in his career, after observing the finches of the Galapagos Islands. He visited these teeming shores of the tropical East Pacific in 1835, during his famous circumnavigation of the globe. One passage in his Journal of Researches into the Geology and Natural History of the Various Countries Visited by H.M.S. Beagle (a work usually published under the more compact title The Voyage of the Beagle) describes his reaction to the markedly different beaks of the six species of Galapagos ground finches: `Seeing this gradation and diversity of structure in one small, intimately related group of birds, one might really fancy that from an original paucity of birds in this archipelago, one species had been taken and modified for different ends.' A woodcut showing four finch heads in profile appears next to this statement, further suggesting that these birds were key to the development of Darwin's ideas about biological evolution. But as Frank Sulloway of Harvard University has shown, the familiar story of `Darwin's finches' that many people learned in school is mostly just that-a story. In actuality Darwin gathered few examples of these supposedly crucial birds. He failed to recognize the importance of the specimens that he did collect and neglected to so much as tag each one with the name of the island from which it came. Indeed, Darwin did not even realize that some of these birds were finches until six years later, when John Gould, an eminent British ornithologist, set him straight. One reads gushing descriptions in The Voyage of the Beagle only because Darwin revised the text of his journal in 1845 to reflect what he had pieced together in the intervening years. His original account says very little about the finches, reflecting the minimal attention he paid to these birds when he first saw them." (Sanderson, J.G., "Testing Ecological Patterns," American Scientist, Vol. 88, No. 4, pp.332-339, July-August 2000, p.332)

and 7) in addition to Darwin's "Seeing this gradation and diversity of structure in one small, intimately related group of birds, one might really fancy that from an original paucity of birds in this archipelago, one species had been taken and modified for different ends"; 8) "A woodcut showing four finch heads in profile appears next to this statement, further suggesting that these birds were key to the development of Darwin's ideas about biological evolution" (see graphic above).

This will be included with a number of other examples in my `Evolution Quotes Book' and in my "Problems of Evolution" under "Darwin's Dishonesty'. As Darwinist pioneering geneticist C.D. Darlington noted, "Darwin was slippery" with "a flexible strategy which is not to be reconciled with even average intellectual integrity":

"These were virtues or accidents. But side by side with them were what I shall describe as vices. These, we now have to admit, were almost as great a help, almost as valuable a combination in achieving his success, as the virtues that accompanied them. By that I mean his public and political success in mass conversion. These vices were of three kinds: a conservative outlook in every respect except the evolutionary hypothesis; a failure to recognize or to relate his own ideas, his larger ideas, with those of others working in the same field; and a flexible strategy which is not to be reconciled with even average intellectual integrity: by contrast with Wallace, Lyell, Hooker, Chambers or even Spencer, Darwin was slippery." (Darlington, C.D., "Darwin's Place in History," Basil Blackwell: Oxford UK, 1959, p.60)]

Coontinued in part #6.

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

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