Uncommon Descent Serving The Intelligent Design Community

Introgressive hybridization and the Galapagos finches


A branching pattern of variation was central to Darwin’s concept of speciation. As one population of organisms follows one trajectory, another population may spin off in a different direction. When they are sufficiently far apart, they are considered to be separate species. The Galapagos finches have been regarded as exemplars of Darwinian transformation, even leading to the claim that one newly developed population is “behaving as a separate species”. However, the most recent study, from one of the smaller islands (Floreana), concludes that the most likely cause of the disappearance of one of these species is hybridization.

“The authors suggest that hybridization may have been responsible for the disappearance of the large tree finch from Floreana, and that it may now be causing the remaining two species to fuse into one: speciation in reverse.” (p.179)

Please can we have some realism from researchers adhering to the Darwinian paradigm. In the main, their research findings cast light on ecology but they are failing to touch the real challenges facing evolutionary biology.
Of the greatest urgency is attention to educational textbooks. For too long, the Darwinists have maintained a hegemony that resists all critiques of their arguments. Typically, they present any questioning of their interpretation of the evidence as religiously motivated and anti-science. For the good of science, this situation has to change.

For more, go here.

The primary objective takeaway from the finch beak observations (and the peppered moths and the bacteria resistance to antibiotics, etc., etc.) is that, in response to environmental changes, populations tend to oscillate around a norm while ultimately resisting fundamental change. That is the real takeaway from the alleged examples of speciation or the breathless claims of "natural selection in action". Eric Anderson
Mahuna, From what I recall of Origin, Darwin repeatedly remarks on there being many species of pigeon. Perhaps you’re referring to where Darwin argued that there was one species of domestic pigeon which, he argues, derived from the rock pigeon. Apparently, that’s still the general belief today: http://en.wikipedia.org/wiki/Domestic_Pigeon As for Darwin not knowing what a species is - does anyone? That’s been one of the most disputed topics in biology for centuries. Many animals are considered separates species and, yet, can readily interbreed. There are breeds of dog that cannot interbreed, but they are considered one species. The usage of “species” is quite inconsistent. But, anyway, I don’t think Darwin said that there were three species of dog, but rather that dogs are the result of the hybridization of several wild species. (A debated subject until genetic testing was done.) goodusername
In "Origin of Species", Darwin declares that in the entire world there is exactly one (1) species of pigeon. Wikipedia states that there are "about 310 species" of pigeon. Darwin then declares that there are exactly 3 species of dog. We now accept that there is exactly 1 species of dog, with chihuahuas and Great Danes being breeds within that species. So, Darwin had no idea what "species" meant, and holding 2 unrelated pigeons in his hands insisted they were the same, while claiming the 2 dogs at his feet were different. The man was simply making wild guesses and had nothing we would consider "science" behind any of those guesses. Late 19th century Socialists and other atheists found his crackpot ideas useful, and so made "evolution" their Creation Myth, since no respectable philosophy can exist without explaining Creation. mahuna
Read Jonathan Weiner's book, "The Beak of the Finch." Same bottom-line: after two rain-soaked years, two 'species' of finch that 'never' mated, began to mate. And, as the study went forward, began to dominate the population of finches on the island. If you read the book, there's a clue early on to what appears to be some rule, or law, of adaptation existing on the island, and perhaps applicable outside. I sort of find it humorous that good field biologists can't pick up on this. But, of course, 'picking up' on this would harm the interpretation of Darwinian theory. A definite no-no in the academy. PaV
This is from the article "Is Evolution a Fact?" from the September 2006 issues of Awake! magazine: "Modern evolutionists teach that as species spread and became isolated, natural selection chose those whose gene mutations made them most fit for their new environment. As a result, evolutionists postulate, these isolated groups eventually developed into totally new species. As previously noted, the evidence from research strongly indicates that mutations cannot produce entirely new kinds of plants or animals. Nevertheless, what proof do evolutionists provide to support the claim that natural selection chooses beneficial mutations to produce new species? A brochure published in 1999 by the National Academy of Sciences (NAS) in the United States says: “A particularly compelling example of speciation [the evolution of new species] involves the 13 species of finches studied by Darwin on the Galápagos Islands, now known as Darwin’s finches.” In the 1970’s, a research group led by Peter and Rosemary Grant began studying these finches and discovered that after a year of drought, finches that had slightly bigger beaks survived more readily than those with smaller beaks. Since the size and shape of the beaks is one of the primary ways of determining the 13 species of finches, these findings were assumed to be significant. “The Grants have estimated,” continues the brochure, “that if droughts occur about once every 10 years on the islands, a new species of finch might arise in only about 200 years.” However, the NAS brochure neglects to mention some significant but awkward facts. In the years following the drought, finches with smaller beaks again dominated the population. Thus, Peter Grant and graduate student Lisle Gibbs wrote in the science journal Nature in 1987 that they had seen “a reversal in the direction of selection.” In 1991, Grant wrote that “the population, subjected to natural selection, is oscillating back and forth” each time the climate changes. The researchers also noticed that some of the different “species” of finches were interbreeding and producing offspring that survived better than the parents. Peter and Rosemary Grant concluded that if the interbreeding continued, it could result in the fusion of two “species” into just one within 200 years. Back in 1966, evolutionary biologist George Christopher Williams wrote: “I regard it as unfortunate that the theory of natural selection was first developed as an explanation for evolutionary change. It is much more important as an explanation for the maintenance of adaptation.” Evolutionary theorist Jeffrey Schwartz wrote in 1999 that if Williams’ conclusions are correct, natural selection may be helping species to adapt to the changing demands of existence, but “it is not creating anything new.” The main point is here: Indeed, Darwin’s finches are not becoming “anything new.” They are still finches. And the fact that they are interbreeding casts doubt on the methods some evolutionists use to define a species. In addition, they expose the fact that even prestigious scientific academies are not above reporting evidence in a biased manner. Barb

Leave a Reply