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The Beak Of The Finch -
A story of evolution in our time
by Jonathan Weiner, 1994

In response to my Evolution FAQ, a participant recommended I read this book. So here goes.

Getting through this one was a chore. I had to renew the book from the library twice - the maximum - and even then it went overdue before I could force myself to finish it and write up this report.

If you expect to find any description or explanation of the evolution of new body parts, these 300 pages will be a waste of your time. Don't expect to read of evidence - or speculation, even - of how the 13 Galapagos finch species got their different beak shapes. All of the so-called evolution which the author and the main characters gush over is limited to tiny shifts within the bounds of variations that already exist within a species.

Peter and Rosemary Grant and other members of their team have been making detailed observations of finches on one island in the Galapagos since 1973. The main measurements they take are dimensions of the finch beaks. They are very precise measurements, indeed:

(Page 5) "Beak length, 14.9 millimeters," Peter recites. Beak depth, 8.8. Beak width, 8 millimeters."

I hope all of the team members are in agreement as to where the beak starts, exactly.

As in all writings on evolution, it seems, you will find loads of ammo from the skeptics' camp. Here are some passages early in the book; there are more further down.

(Page 6) The Origin Of Species says very little about the origin of species. Darwin's full title is On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. Yet the book does not document the origin of a single species, or a single case of natural selection, or the preservation of one favored race in the struggle for life.

(Page 7) Fossils argued that evolution has happened. Logic argued that natural selection can make it happen. But neither bones nor logic could demonstrate the one leading to the other, natural selection causing evolution. In 1893, in an essay entitled "The All-Sufficiency of Natural Selection", the German biologist August Weismann confessed "that it is really very difficult to imagine this process of natural selection in its details; and to this day it is impossible to demonstrate it in any one point."

(Page 8) In 1990, in a one-volume Encyclopedia Of Evolution, a physical anthroplogist wrote that the "complaint of a half-century ago holds good: The number of experimental tests of natural selection is pitiful; the few that have been conducted still do heavy duty as examplars."

What Weiner intends to show is that

(Page 8-9) Biologists are observing year by year and sometimes even day by day or hour by hour details of life's unrolling and opening, right now.... [Darwin] vastly underestimated the power of natural selection. Its action is neither rare nor slow. It leads to evolution daily and hourly, all around us, and we can watch.

(Page 16) With the conditions of life on this planet changing everywhere faster and faster, the pressures of natural selection are everywhere increasing in intensity, daily and hourly, even on islands as remote as the Galapagos. Whether or not we choose to watch, evolution is shaping us all.

During the period of the finch watch, there were 2 extraordinary meteorological events: an extreme drought in 1977; and extreme rainfall due to El Nin~o in 1983. Only one in 7 finches survived the drought, with more of the smaller finches getting killed off. The larger finches - with larger beaks - survived better. Their offspring also had larger beaks... Natural selection! Evolution! In Weiner's words:

(Page 78) And what made the difference between life and death was often "the slightest variation," an imperceptible difference in the size of the beak, just as Darwin's theory predicts.

Something tells me you'd get much the same result if you put human beings on a thousand mile forced march. I'll bet you the offspring of the hardier humans who survived would have bigger noses.

The 1983 El Nin~o was probably the strongest of the 20th century (page 100). It had the opposite effect of the drought; the larger finches died. The explanation of why the big birds had a rough time with a superabundance of small seeds sounded strained to me. My mouth handles potatoes, and it handles rice grains, too.

In any case, the net effect was to undo the effects of the drought. The author enthuses:

(Page 106) Not only can evolution push a species fast in one direction. Evolution can reverse directions and push it back just as swiftly.

As for me, I'm disappointed that we don't seem to be getting anywhere.

(Page 192) The width of the [medium ground finch] beak... is measurably narrower [in 1991] than the beaks of the generation before them - down from 8.86 millimeters at the time of the flood to 8.74 millimeters now. That does not take [medium ground finches] back where they were at the start of the Grants' watch, but nearly so.

The author unwittingly details another recent, major catastrophe in the lives of the finches.

(Page 145) To find out what the [Galapagos] finches were eating, [American ornithologist Robert] Bowman shot them by the hundreds and inspected the contents of their stomachs.

But, no, there isn't a single word about how evolution responded that upheaval. Another instance of a major change for one of the finch species was a big decrease in the number of cacti.

(Page 192) In spite of all this selection pressure [that is, diminished numbers of cacti], the cactus finches have not changed in the last ten years. By all the Grants' measures, their beaks and bodies are the same now, on the average, as before the flood. This too makes sense in terms of the adaptive landscape, because in evolutionary terms these birds have nowhere to go.

Very convenient... It makes perfect sense when a species evolves in response to such changes; and it makes perfect sense when it doesn't.

Given the fuzziness of the notion of species in general, it's no surprise that there is some fuzziness as to whether the 13 Galapagos finch species are really separate species.

The Grants have focused on the ground finches because they are easy to watch. Three species of the ground finches are the large, medium and small ground finches. They have, respectively, large, medium and small beaks (surprise!) Page 42: "Within each of these three species, the beaks of the individual birds are variable." Thus, the largest small ground finches (and their beaks) are as big as the smallest medium ground finches. Likewise, with the largest medium ground finches and the smallest large ground finches. How they can tell themselves apart is a good question, one which the Grant team devoted some effort to.

Still, the 13 species rarely interbreed. At least that was the case before the floods of 1983. For some reason, after the floods, there has been much more interbreeding. The extent of this hybridization caused a gear shift in the thinking of the finch watchers. Where natural selection had been the be-all-and-end-all up to that point, now they think hybridization is a big part of the evolutionary picture.

(Page 158) As [the Grants] contemplate the rise of the hybrid finches, they are beginning to suspect that selection and crossing [between existing species] work together as part of the same creative process.

Besides giving the impression of another "theory du jour", this all remained a little unclear to me - partly because I wonder how you can have hybrids until you've developed different species or breeds in the first place. In any case, it sounds like hybridization is undoing a lot of evolution:

(Page 206) Roughly one out of ten birds born on [the island] now are hybrids, and the hybrids are doing better than any of the others on the island. In a blink of evolutionary time, all of Darwin's finches could run together and congeal...

Again, it would have been a lot more fascinating to read about the appearance of new and fantastic finches on the island. I liked this little typo:

(Page 141) [Darwin's] vision had nothing to do with... the matings of hybirds.


(Page 19) "Peter Grant's service to biology has been extreme," says William Hamilton, an evolutionist at Oxford university. "He has shown that the most important and pervasive theory that biology has really does work, and that almost all of the varied and fine details of evolution that he has found occurring are understandable by this theory, and, so far, seem to need no other.... I think it can be claimed that the [Grant group's] work as a whole give the most detailed unified support to the Neo-Darwinian view of evolution that the theory has yet received."

What rankles me about that passage is that nowhere in the book are we told what "neo-Darwinism" is, or how it relates to Darwinism. As I've expressed elsewhere, it seems that evolutionists won't hang up a stationary target.


(Page 39) Variation is both universal and mysterious, one of the deepest problems in nature, and for Darwin it was for a long time completely bewildering. He wondered why, if his thinking was right, we see any species at all. Why not a continuous spectrum from tiny individuals right on up the scale to kingdoms? Why for instance do we find a vampire finch and a vegetarian finch?... Why not a whole smooth series of omnivores between the two, with a perfect series of intermediate beaks? Why not a blur, a chaos, an infinite web... of continuous variation?

(Remember that there are those in who say that this is exactly what we do see.) Weiner explains it this way:

(Page 39) When we look around us... the species of animals and plants we see are survivors. Varieties in between them have died off and disappeared...

Does that work for you?

There was a discussion (page 91) of a study of the colorful spots on guppies. The guppy spots attract mates and predators. Over the course of generations the spots "evolve" to more or less gaudy depending on the type of predators around, and the mottling of the stream bed.

That's all very interesting, but I still wonder why Darwinism wouldn't give rise to a thousand other solutions. Why wouldn't females start to prefer the drabbest males? Why don't the males evolve shells, poisons, or killer teeth?

There is a story (page 107) which seems to me another example of what I call the "ouija board" effect in science - an unconscious massaging of the data until it says what you want it to. Jamie Smith observed natural selection in song sparrows over a period of years. He analyzed the data and concluded there was no evolution. But Dolph Schluter was determined to find evolution - and he did! Even though the birds ended up the same as when they started, he managed to find tiny variations year by year.

(Page 108) Dolph says, "A species looks steady when you look at it over years - but when you actually get out the magnifying glass you see that it's wobbling constantly. So I guess it's evolution in action. The world is not as stable as you think!"

No doubt if you had gone over your grandparent's generation with a pair of calipers you would've found some measurement which differs slightly from your own generation (if not in actuality, at least as a artifact of the measuring process.)

Well into the book there is more ammo for the skeptics. I was more than a little surprised myself to see how badly Darwinism had fallen out of favor earlier in this century. (Made me wonder if is the only surviving bastion of support, and why I went to the trouble to write that little essay in the first place...)

(Page 129) After Darwin's death, many biologists found it easy to accept evolution and impossible to accept Darwin's chief explanation for it. Evolution, yes; selection, no. William Bateson, the founder of modern genetics, wrote an elegy for Darwinism in 1913, calling it "so inapplicable to the facts that we can only marvel... at the want of penetration displayed by the advocates of such a proposition."

Nordenskiold's History Of Biology dismissed Darwinism forever in 1924:

To raise the theory of selection, as has often been done, to the rank of a "natural law" comparable in value with the law of gravity established by Newton is, of course, quite irrational, as time has already shown; Darwin's theory of the origin of species was long ago abandoned.

And Singer's A Short History Of Biology killed Darwin with kindness in 1931:

...natural selection by the survival of the fittest, is certainly far less emphasized by naturalists now than in the years that immediately followed the appearance of Darwin's book. At the time, however, it was an extremely stimulating suggestion.

As part of the 1981 permanent exhibit "The Origin Of Species" at the British Museum's Natural History Building, a film loop tells visitors:

(Page 130) The Survival of the Fittest is an empty phrase; it is a play on words. For this reason, many critics feel that not only is the idea of evolution unscientific, but the idea of natural selection also.... The idea of evolution by natural selection is a matter of logic, not science, and it follows that the concept of evolution by natural selection is not, strictly speaking, scientific.

That sparked a year-long debate in Nature magazine.

(Page 130) Even Darwin himself admitted twinges of doubt. He asks in the Origin: "Can we believe that natural selection could produce, on the one hand, an organ of trifling importance, such as the tail of the giraffe, which serves as a fly-flapper, and, on the other hand, an organ so wonderful as the eye?" And though he answers in the affirmative, the question is more than rhetorical, for in a letter to a friend, Darwin confesses:

"I remember well the time when the thought of the eye made me cold all over, but I have got over this stage of the complaint, and now small trifling particulars of structure often make me very uncomfortable. The sight of a feather in a peacock's tail, whenever I gaze at it, makes me sick!"

If you expect the author to come charging back in shining armor on a white horse to slay these doubts, here's what you get:

(Page 131) Watching natural selection in action is one way to get beyond the debates and abstractions that have wrapped this subject in a century and a half of philosophical fog. The Grants can look and see. And this year [1991], with the help of hybrids, they hope to see a little more than they have seen before.

A scientist named Robert Bowman made an interesting observation:

(Page 145) Time and again Robert Bowman watched the sort of mixed flocks that Darwin himself had noticed when he first got off the Beagle. Time and again he saw four or more species of ground finches feeding in the very same bush, small peaceable kingdoms of ground finches. "And since there is no evidence that competition is occurring at the present time," Bowman declared in his thesis, "I see no logical reason to assume that it must have occurred in the past."

To argue that the absence of competition is proof of its power seemed to Bowman infuriatingly circular [?] reasoning.

The invoking of computer modeling may cause a twinge of embarrassment.

(Page 153) Peter Grant had asked [Dolph Schluter] to find a way of pulling together all the group's work on beaks and seeds in one framework; to create an all-embracing mathematical model that would help the finch watchers understand what they were seeing. Dolph decided to draw their data in terms of adaptive landscapes, with the aid of computers...

Dolph fed in all of the information on beak sizes and seed sizes.

(Page 153) Then he programmed the computer to calculate how many finches a hypothetical island could support....

Dolph assumed it would draw a peak corresponding to the best of all possible beaks, that is, the beak that would produce the maximum number of finches on that idealized Galapagos island.... The valleys on either side of the peak would represent all the miscellaneous beak sizes that were relatively unfit.

He set the computer going, and he was thrilled by what he saw. The computer did not draw a single peak. Instead it drew three peaks, with deep valleys between them.

What the computer noticed was that there are three categories of seeds - soft, medium and hard - and came up with a beak for each. Hooray for computers.

Similarly, on page 205, we read about the "succinct mathematical formula" that takes into consideration heritabilities of beak dimensions and seed abundances. The researchers plugged in the 1984 values, and the formula predicted the 1987 beak dimensions - to within a hundredth of a millimeter! Whew, that's some formula! Take that, you who criticize natural selection on the grounds that it doesn't submit to quantitive predictions.


(Page 180) How did blind creation make so many new kinds of tools?... As one of Darwin's early critics writes, it is hard "to see how such indefinite oscillations of infinitesimal beginnings can ever build up a sufficiently appreciable resemblance to a leaf, bamboo, or other object, for Natural Selection to seize upon and perpetuate."

No one has ever put this problem more forcefully than Darwin himself, in the Origin. "To suppose that the eye with all its [complexity] could have been formed by natural selection, seems, I freely confess, absurd in the highest degree," he writes.

(Page 181) Richard Dawkins defends Darwin's position vigorously in his book The Blind Watchmaker.... Dawkins argues that selection on even the slightest nubbins and rude beginnings can build up instruments as complicated as watches, telescopes, or the human eye. As long as each stage in the evolution of a complex adaptation is adaptive for its own sake, it is likely to be preserved within each generation and embellished by the next, by Darwin's process of natural selection.

"Likely to be... embellished"??? Surely such a phrase implies some sort of guiding force. How can random mutations be likely to embellish anything when they can head off in any number of directions with equal probability?


(Page 218) But every living thing carries its [genetic] code in the same invisible characters, always the same four letters [G, A, T, C], because ultimately every living thing shares the same ancestor, about four billion years back, near the birth of the planet.

That does not follow logically. There may be reasons why life appearing at different times and places always uses the same "four letters".


(Page 231) But evolutionists are forever dividing and subdividing into schismatic sects, Kingdoms of Either and Or. Do new species arise in [geographic isolation], or do they arise among neighbors? Is the origin of species fast or slow? Is the mechanism natural selection or sexual selection? And so on.

But Weiner assures us that "none of these questions really have to be framed either-or." Thanks.

On the subject of the isolation of species - generally, or in the Galapagos - here are 3 passages of interest:

(Page 141) But Darwin's finches are not marooned, each species to its own island. On average there are 7 or 8 species to each island in the archipelago. Beyond that there is the constant traffic of visiting finches. The birds may have diverged - or begun to diverge - in isolation, but they are not in isolation now.

(Page 138) So there are endless streams of wanderers between the islands.... [Darwin's finches] are still wandering and straying across their islands, all across the archipelago. The Rothschild expedition at the turn of the century spotted a single specimen flying many kilometers out at sea.

(Page 246) Around the world almost one hundred species of birds are known to have gone extinct since the 17th century, together with more than 80 subspecies; more than 9 out of 10 of these lost species and subspecies lived on islands.

Taking a look at microscopic life, here may be what was for me the most interesting passage in the whole book:

(Page 258) It is easy to start a resistance movement in the most common bacteria in the human gut, E. coli. First, one establishes a colony of E. coli in a Petri dish. The bacteria multiply so rapidly that a single microscopic cell can grow into a visible pile of 10 million E. coli between morning and mid-afternoon....

Next, one doses the colony with an antibiotic. As fast as it grew, the colony disappears. Only a few cells in the colony have survived - the one or two or three cells that carry a rare resistance gene for that antibiotic. These several survivors multiply and pass their successful gene to their descendants. Soon there is a new colony in the dish, a colony in which virtually every member cell is resistant to the antibiotic.

And to think that in a few hours some of the resistant bacteria could be parenting new colonies half-way around the world, having flown there in the gut of some businessman. Fascinating! BUT... notice, as in the case of the moths "evolving" from light to dark and back again depending on the soot on the trees, we haven't gotten any new creature that didn't already exist.

Weiner gives another interesting example: how elephants are becoming more tuskless where they were being poached for their tusks. The tuskless elephants avoid being poached, and then pass on their tusklessness.


(Page 55) It was some time after [British ornithologist David] Lack got home to England [about 1938] that, like Darwin before him, he did a double-take. As he looked over his data he noticed that the species of finches whose beaks are most nearly identical do not live together on any of the islands in the archepelago.... Lack had never seen breeding colonies of both cactus finches (G. scandens and G. conirostris) on any one island. What is more, if two finch species with rather similar beaks do share an island, their beaks are more divergent in their measurements on that island than they are elsewhere. That is, the longer beak is longer than average, and the shorter beak is shorter than average, almost as if they were consciously trying to get out of each other's niches. Lack found these patterns in case after case, not only in his own data books, but also in measurements of the thousands of museum specimens that had been collected since Darwin.

(Page 145) Lack pointed out that on Santa Cruz the small beaks [of the small-beaked species] are small and the medium beaks [of the medium-beaked species] are medium. On Daphne, where there are very few small beaks, the medium beaks have become smaller. On Los Hermanos where there are very few medium beaks, the small beaks have become larger. Lack saw this pattern with many other pairs of finches on the islands...

Admittedly, all quite interesting, too. It's almost enough to get you wondering about the notion of "niches". For half a second. If the circularity of the concept isn't obvious, notice you've just shifted the problem from explaining the creation of species to the creation of "niches" - and why there isn't one for a medium ground finch with 360 degree vision and a 195 IQ.


Comments on the above book report

In June 2000 I invited participants to read the above book report on "The Beak Of The Finch." Here is a brief discussion of the most significant comments. If desired, you can track down the complete postings using I used the subject line, "Welcome to my evolution FAQ - round 4."

Matt Silberstein and Mark VandeWettering were both miffed that I didn't mention the book winning the Pulitzer Prize for science writing. Silberstein wrote: "You did know that, didn't you?" Well, no, actually. I did notice in the acknowledgments that the Grants were very reluctant to have the book written.

Silberstein wrote: "And you did notice that the book was not about the evolution of 'new body parts' (whatever that means)..."

New body parts are anatomical features present in a given species which the ancestors of that species did not possess. It would seem to me that someone who can't fathom "new body parts" is obliged to believe in the completely independent origins of the species.

Regarding the observation that the beak sizes of the survivors of a terrible drought were larger than the preceding average, I wrote "Something tells me you'd get much the same result if you put human beings on a thousand mile forced march. I'll bet you the offspring of the hardier humans who survived would have bigger noses."

To Silberstein, this was ridiculous. He wrote: "Why?"

To VandeWettering, it was self-evident. He wrote: "Well, yes. That is an example of natural selection and evolution as well."

Oh well, the important thing is to keep up the attack. I'm reminded of my earlier argument in that the human race is "special"; that there couldn't be alien races out there as advanced as humans - else, we'd know about them. Half of t.o. screamed, "The galaxy is sick with intelligent populations, you moron!" The other half hollered, "Just because we're the only ones, how does that make us special??? Somebody has to win the lottery, you nitwit!"

Silberstein wrote: "Yep, Darwin did fall out of favor. But with the modern synthesis (something you don't know about, but ignorance does not seem to be a barrier for you) Darwin rose again."

I presume modern synthesis is the same as "Neo-Darwinism", or forms part of it, or overlaps with it. The word appears twice in the Pulitzer Prize award-winning "The Beak Of The Finch", but without a single sentence explaining or defining it.


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