Darwin’s Finches Are Evidence for Evolution? Think Again

Darwin's finches or Galapagos finches. Darwin, 1845. Journal of researches into the natural history and geology of the countries visited during the voyage of H.M.S. Beagle round the world, under the Command of Capt. Fitz Roy, R.N. 2d edition.

By Michael Denton Published on February 11, 2016

Today is Darwin Day, marking the birthday of Charles Darwin. As the world looks back on the achievements of the great man, you are likely to see many “icons of evolution” triumphantly displayed. These famous, yet often flawed, success stories of Darwinian theory are held up as reasons to believe that the neo-Darwinian synthesis and everything it entails — scientifically and philosophically — has vanquished all legitimate challenges. But that is not so.

One of the most famous such icons is a small group of birds, an inspiration for Darwin’s On the Origin of Species, that populates a remote cluster of islands in the equatorial Pacific. The Galápagos finches, with their different beak sizes, are brandished as one of the clearest examples of evolution at work.

However, that is true up to only a very limited extent. These birds are, indeed, a clear example of micro-evolution. They are closely related to each other and their beaks have obviously been adapted through natural selection to the different food sources on the various islands. However, the finches also show what is required in order to expand the mechanism of natural selection to the larger or macro scale.

The Galápagos finches put on display the two strict requirements that must be present in order for natural selection to work its magic. If these two factors are not present, natural selection is impotent to change any creature at all, much less create a new species.

First, the finches’ beaks are clearly adaptive. Each distinct variation gives the lucky individual a definitive leg-up in its specific environment. There is an obvious, practical reason why the differentiation is helpful to the species in question. This is absolutely essential in order for natural selection to pick between variations in species. Natural selection can only “see” those variations that are adaptive — causing one individual to live, and carry on its genes, and another to die and not leave offspring. If a variation is neutral or does not somehow increase fitness in the specific environment the creature lives in, Darwin’s mechanism cannot select it.

Second, there is a functional continuum among the finches’ beaks. That is, between a finch with a tiny beak and a finch with a large beak, there are tiny, step-by-step changes, and each change makes the creature slightly more fit in its environment. This is also essential for natural selection to work.

The problem for Darwinian theory comes in explaining evolutionary change where, unlike the case of Darwin’s finches, these requirements are absent. First, there may not be a continuum. That is, natural selection cannot make large jumps or drastic changes. There must be small steps. Secondly, each single step must be beneficial to the individual. It is not enough for the first and last versions of the adaptation to be helpful — all the intervening steps must increase fitness as well.

There are examples of creatures throughout the biological world that break one or both of these rules. Many creatures just don’t fit the natural selection story like the Galápagos finches do.

For example, what is the adaptive significance of the many examples of geometric or abstract forms we see in the world, such as the shapes of leaves or the concentric whorls of flowers? Or consider the case of the enucleated red blood cell in mammals, which was the subject of my postdoctoral work. Not only have we found no obvious reason that such features increase fitness, there is no plausible continuum leading from a blood cell that keeps its nucleus to one that ejects it.

There are no such intermediate forms in nature, and it is impossible to plausibly imagine intermediates that are even stable, much less adaptive. I document many more examples in my new book, Evolution: Still a Theory in Crisis.

Without workable explanations for these many anomalies, Darwinian evolution may just go the way of Newtonian physics — applicable to a small area where specific rules apply, but unable to make universal statements about the world in general.

So when you see the media promoting the Galápagos finches as evidence for Darwinian evolution this Darwin Day, take it with a grain of salt. Not every species in the world is as obliging to the requirements of Darwinism as the famous finches. And this is just the beginning of life’s richness and complexity that cannot be reduced to Darwinian biology.

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  • ARB

    While I agree with the general thought, and many of my own reflect these, I find some of these assertions uncertain. Specifically, a sequence of evolutions does not necessarily need to be a strict improvement at every stage to be tenable; it only must not be fatal at each stage. However, this requires substantially weakened selection demands, in which case the adaptation is likely not an selectable advantage and thus cannot achieve dominance within the species. This can still work, but it requires oscillating selection criteria: a species must encounter an effective balance of fat and plenty, and times of scarcity, in order to improve overall via natural selection. Too much scarcity, and only scarcity-optimized traits are preserved (or the species simply dies off). Too much fat and plenty, and the selection tends towards rapidly reproducing traits, which is usually deleterious to the fitness of the overall species. The only saving grace of the theory is that oscillating selection criteria may actually be intrinsic to certain life cycles, such as the traditional “hares and wolves” cycle found so often in differential equations textbooks.

    And the importance of continuity cannot be underestimated. It is this trait which I believe is most untenable in the evolutionary theory. While it is easy to see natural selection acting on *geometric* deformations, like the shape of a beak or the concavity of a simple eye, what we must really be concerned with is a form of *genetic* continuity which is poorly understood. It is not enough, as some evolutionists have argued, to show that every step in a continuous deformation from a light-sensing patch to an eye concavity is an improvement; evolution is not a homotopy of the creature, defined on a distinct time span [0,1] with start 0 and end 1, but rather it is a function tracing a complex sequence of discrete genetic code with bizarre continuity conditions. If such a homotopy argument is used, we must assume that there is a reasonable approximation to each of these given stages of eye geometry within this genetic code space, and that these are assigned a reasonable probability within the stochastic process describing genetic (not geometric) evolution. And while this is certainly not impossible, the mind-boggling complexity of this problem makes it nearly impossible to demonstrate the theory, or even argue its plausibility out of anything more convincing than secular scientific principle and the lack of a better natural theory.

  • tj10

    “Second, there is a functional continuum among the finches’ beaks. That is, between a finch with a tiny beak and a finch with a large beak, there are tiny, step-by-step changes, and each change makes the creature slightly more fit in its environment. This is also essential for natural selection to work.”

    I fully agree with this point! In most instances, the idea that such a continuum exists between point A and point B is just assumed. They don’t really know if such a continuum really exists, but they think it has to exist because they think evolution is true. But this is not science. This is true of so many evolutionary changes.

    One such transition that Dr. Denton wrote about in his first book was the transition from a dinosaur bellows type lung to a blow through bird lung. Since then, it has been pointed out that there is some evidence that perhaps therapy dinosaurs had a similar flow through type lung. But that really doesn’t solve the problem. The flow through type lung had to evolve from a different type lung somewhere in the past. Where did the therapod dinosaur get this lung – if indeed it really is a flow through lung? Does a continuum exist from one type of lung to another type of lung whereby each little step is beneficial and gives the organism enough of a survival advantage to be selected for?

    This is incredible to me. Such a claim is clearly hard to believe so I would think it would demand some concrete evidence to be taken seriously.

  • Dale Warren

    “For example, what is the adaptive significance of the many examples of geometric or abstract forms we see in the world, such as the shapes of leaves or the concentric whorls of flowers?”

    Actually the adaptive significances are very clearly understood. Leave shapes can have several different advantages. Surface area helps gather light for photosynthesis.. But shape channels rainwater in beneficial ways. (Ie: to avoid drowning the plant, to focus light, etc.)
    Other examples : concentric whorls on Flora can act as visual lures or visual warnings to creatures who’s brains take note of patterns.
    Birds, for example are vital to certain plants’ reproductive strategies. The spoor is ingested, and spread through defecation. The bird feces also act as manure to help germination. The attractive plant spreads while the other does not.
    Bees, are another example. Pattern recognition indicates which flowers are and are not suitable.. The bumble bee then pollinates one, but not the other.

    Other times, such as with a trees rings… There is a pattern… But it isn’t related to natural selection. Its simply a manifestation of the plants growth cycle and climate.

    So yeah.. Strike one I guess. I’m not a formally educated person, but I can rebuff these “proofs”.

  • John Emigh

    I see the adaptive point. But also, has anyone shown it was a mutation in DNA? Or was it just bringing out DNA that was already present. Do the finches have anything to say about mutation of DNA? Or only addresses the natural selection part of the equation?

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