Tag Archives: Finches

Are the Galapagos finch beaks evidence of Darwinian evolution?

I have a key that will unlock a puzzling mystery
I have a key that will unlock a puzzling mystery

Jonathan Wells has an article about it at Evolution News.

It says:

When Charles Darwin visited the Galápagos Islands in 1835, he collected specimens of the local wildlife. These included some finches that he threw into bags, many of them mislabeled. Although the Galápagos finches had little impact on Darwin’s thinking (he doesn’t even mention them in The Origin of Species), biologists who studied them a century later called them “Darwin’s finches” and invented the myth that Darwin had correlated differences in the finches’ beaks with different food sources (he hadn’t). According to the myth, Darwin was inspired by the finches to formulate his theory of evolution, thoughaccording to historian of science Frank Sulloway “nothing could be further from the truth.”

In the 1970s, biologists studied a population of medium ground finches on one of the islands in great detail. When a severe drought left only large, hard-to-crack seeds, 85 percent of the birds perished. The survivors had beaks that were about 5 percent larger than the average beak size in the original population. The biologists estimated that if similar droughts occurred once every ten years, the population could become a new species in only 200 years. In a 1999 booklet defending evolution, the U.S. National Academy of Sciences called the finches “a particularly compelling example” of the origin of species.

But after the drought, birds with smaller beaks flourished again, and the average beak size of the population returned to normal. No net evolution had occurred. No matter; Darwin’s finches became an icon of evolution that is still featured in most biology textbooks.

In the 1980s, a population of large ground finches, with larger beaks than the medium ground finches, migrated to the island. When a drought in 2004-2005 again reduced the food supply, the medium and large ground finch populations both declined. But since even the largest beaks among the medium ground finches were no match for the beaks of the large ground finches, the latter pretty much monopolized the larger seeds and the former had to make do with smaller seeds. This time, the medium ground finches that survived the drought had beaks that were smaller than the average size in the original population. Biologists studying the finches argued that birds with smaller beaks were better able to eat the tiny seeds that were left after the large ground finches ate the big ones, and they concluded that this was again an example of “evolutionary change.”

[…]Wait a minute. Average beak size increased slightly during one drought, only to return to normal after the rains return. Then average beak size decreased slightly during another drought. A region of DNA is correlated with beak size. And somehow that tells us how finches evolved in the first place?

There is an important distinction to make between micro-evolution and macro-evolution. Changes within a type is micro-evolution. Evolving a new organ type or body plan is macro-evolution. There is plenty of evidence for micro-evolution, but no evidence for macro-evolution.

What needs to be proven by the Darwinists is that the same process that results in different average beak size in a population of finches after a drought can create the finches in the first place. I think that Darwinists are credulous – they believe what they want to believe because they want to believe it, even if the evidence is incredibly weak. Darwinists must demonstrate that heritable variations can result in the generation of new organ types and body plans. Changes in average beak size is not interesting. What is needed is to show how the beaks, much less the wings, evolved in the first place.

Icons of Evolution

Jonathan has actually written about a number of  misleading things that you may mind in Biology textbooks.

Here are the sections in his book “Icons of Evolution“:

  • The Miller-Urey Experiment
  • Darwin’s Tree of Life
  • Homology in Vertebrate Limbs
  • Haeckel’s Embroys
  • Archaeopteryx–The Missing Link
  • Peppered Moths
  • Darwin’s Finches
  • Four-Winged Fruit Flies
  • Fossil Horses and Directed Evolution
  • From Ape to Human: The Ultimate Icon

Dr. Wells holds a Ph.D in Molecular and Cell Biology from the University of California at Berkeley.

Wired Science misleads readers on what Galapagos finches really prove

Here’s the article. (H/T Neil Simpson)


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.

Well, that would be very interesting… if it were true. But whenever I’ve heard these finches mentioned, it turns out that what actually happened is that populations of different kinds of finches increase and decrease in response to changing environmental conditions. No finch’s beak actually changes size! Some finches with beaks more adapted to the environmental conditions survive and leave more offspring than other finches who are not as adapted. When conditions change, the changes in populations reverse themselves and return to equilibrium.

Evolution News explains:

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.

Read the rest here. References to peer-reviewed literature are provided.