Darwin Devolves: “Devolution” is Not a Thing

In Michael Behe’s new book, he touts the concept “Devolution” using what he calls the first rule of adaptive evolution, that is, that unguided natural selection usually works through random mutations that damage, diminish, or break the genes in which they occur. To do more than that, the actions of a supernatural intelligent agent are required, according to Behe. (For a more comprehensive review of Behe’s ideas about Intelligent Design, see the first few sections of my recent review of “Darwin Devolves.”)


I have lots of problems with this book. I detail some of them in this review in Science, but I take a detailed scientific look at his opening example in this post, which I think captures Behe’s general approach of presenting data in a very misleading way. But in addition to the problems with his individual claims and examples, the whole concept of “devolution” is rather puzzling and I’d like to expand on that.

You have probably never seen the word “devolution” in a scientific context, because it is not a concept within biological science (as far as I know). Behe uses the terms devolve and devolution to indicate a loss or diminishing of function, as though these were the opposites of evolve and evolution. According to Behe, a protein evolves if it improves in function (or gains a new function), and it devolves if it’s function is reduced, degraded, or destroyed. These are not terms that chemist, biochemists, or molecular biologists use and understand. “Devolve” is a pure Behe-ism.

It also doesn’t make any sense. Evolution simply means change over time, and it is not a steady march toward perfection or increasing complexity. In fact, evolution favors simplicity, efficiency, and streamlining as often as it favors complexity. While it’s possible that Behe is using the term in a jocular manner, there’s no indication of that, and he uses the term repeatedly throughout the book in that very specific way. Let’s call this…

Misunderstanding #1: Behe seems to think that evolution is the accumulation of  complexity. If so, it’s no wonder that he has such angst about it. The reality is that evolution is aimless, sloppy, and produces clunky solutions as often as it does elegant ones. Our own bodies are filled with glitches and goofs left over from the imprecision of natural selection. This may be deeply unsatisfying to some, but nature cares little about our satisfaction.

This fundamental misunderstanding of the nature of evolution is a serious error, especially for someone who has dedicated his career to critiquing modern evolutionary theory. But it not the only one.

Misunderstanding #2: Behe’s notion of “irreducible complexity” demands that natural selection can only work if every single step on an evolutionary path is advantageous. We know that’s not true. Populations of organisms harbor a great deal of genetic diversity generated by gene duplications, neutral mutations (and even slightly deleterious ones), recombination, and even rare but dramatic events like chromosomal duplications or rearrangements, and horizontal gene transfer (which may actually be not as rare as we thought). Evolutionary forces then act on all that diversity in unpredictable ways. In Darwin Devolves, you will not find discussions of any of this. Behe either ignores or quickly dismisses these phenomena, despite the key role they play in the generation of the very complexity that Behe doesn’t think that nature can build.

Misunderstanding #3: Behe frequently speaks as though natural selection (which he often calls Darwinism) is the only evolutionary force and speaks about in only the simplest terms, as if we haven’t learned a great deal since the mid-19th century. Natural selection encompasses many permutations that Behe rarely, if ever, acknowledges including exaptation, sexual selection, and frequency-dependent selection. Moreover, natural selection is joined by other forces such as genetic drift, gene flow, hybridization, and meiotic drive. Behe constantly repeats his refrain that natural selection cannot account for everything we see in nature. Yeah, we know. And we’ve known that for a very long time.

[ED: The “#3 paragraph” above has been revised after Jerry Coyne pointed out some sloppy “semantic errors.” I apologize for being rushed and lazy with my readers and I thank Jerry for helping me get the language precise.]


The tendency to see intelligent design in nature is an old one, but science moved past it long ago. As François Jacob wrote in Science over 40 years ago, “Natural selection does not work as an engineer works. It works like a tinkerer — a tinkerer who does not know exactly what he is going to produce but uses whatever he finds around him… to produce some kind of workable object.”

Because he is an accomplished biochemist, Behe’s writing gives the air of scientific authority. However, the answers to the questions he poses have been worked out for quite some time. In 1918, H. J. Muller proposed a process of how natural selection can create complexity: “Add a part; make it necessary.” Behe has long been skeptical of this perhaps because the precise molecular mechanisms of “make it necessary” can be difficult to figure out after the fact.

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However, “Muller’s two-step” received a powerful update in 2012, which we now call “Innovation, Amplification, and Divergence,” In this study, Andersson and colleagues showed that, under the right conditions, bacteria would naturally evolve to get over a metabolic hurdle through gene duplication and diversification, all in under 2000 generations. That should have been the end of this debate, but Behe and others insist that this incredible study actually supports Intelligent Design since intelligent scientists designed it. Yes, the scientists were smart, but they designed the way to observe the bacteria’s evolution, they didn’t design the evolution itself.

I find it poetic that the very title of this book, Darwin Devolves, is a misnomer. There is no such thing as devolution and there is no great crisis in evolutionary biology. There are, however, a great deal of interesting unanswered questions. Our new era of cheap genome sequencing can begin to interrogate some of these questions. As with all great interrogations in science, the answers will come from the proper interpretation of all available evidence.




21 thoughts on “Darwin Devolves: “Devolution” is Not a Thing

  1. Natural selection is still the only proposed mechanism said to be able to produce the appearance of design without a designer. With exaptation you have to be able to account for the body parts and plans that were involved. And right now you don’t even have a mechanism for producing eukaryotes. Endosymbiosis can only account for the organelles mitochondria and chloroplasts. Eukaryotes are much more than prokaryotes with one of those organelles. So please, stop talking about sexual selection when you have nothing to explain its existence.

    Also Dr. Behe is OK with the premise that organisms were designed to evolve. Devolution can be found with a simple google search. Basically it means to go from an advanced state to a less advanced state. It can happen with societies or genomes.


    1. Oy vey.

      “Natural selection is still the only proposed mechanism said to be able to produce the appearance of design without a designer.” Which, as the text describes, interest nobody interested in evolution but creationists like Behe.

      “you don’t even have a mechanism for producing eukaryotes”. So where have you been these last few years while eukaryotes took its rightful place in the Tree Of Life as sharing more closely related ancestor with Asgard archaea than Asgard archaea shares with other known archaea? [ See for example https://www.nature.com/articles/nature21031 ; disclaimer: I was Katia’s room mate when I practiced at Ettema Lab.]

      “Devolution can be found with a simple google search.” “Flat Earth can be found by a simple google search. How does that reject what the article describes as a term irrelevant to biology (including genomes)?

      Since the appended flagellum question was answered already in the Nature review, I guess we have emptied out the shallow pot of questions motivated by impotent defense of superstition?


  2. And seeing that Dr. Lenski avoided the question I will ask you:

    How can we test the claim that any bacterial flagellum evolved by means of blind and mindless processes, like natural selection, drift or whatever else you have?


    1. Simple, recreate all the conditions and run the experiment. Not so easy a task, and not unique to biology (try recreating a mountain range, and if one can’t, does that mean mountains don’t form naturally?). Increasingly the pieces are coming into clarity, though, so theoretically paleogenomics will be able to do that. Now how can “design” be tested, Frank? Or don’t those advocates have to play by the same rules? Going by Behe, who constantly begs off from supplying comparable level of detail while demanding it of “Darwinists,” the double standard is one of the big defensive modes of people who don’t want to think about most of the data, let alone account for it.


      1. OK, yes, intelligent design can be detected and tested. As Dr. Behe said:

        “Our ability to be confident of the design of the cilium or intracellular transport rests on the same principles to be confident of the design of anything: the ordering of separate components to achieve an identifiable function that depends sharply on the components.”

        So if we see that and nature doesn’t have anything to account for it, we infer intelligent design. That follows Isaac Newton’s four rules of scientific reasoning.

        Also, it is the evolutionists which claim to have a step-by-step process of producing structures like bacterial flagella. That means the onus is on them to demonstrate such a thing. ID, on the other hand, has a step-by-step process for determining whether or not intelligent design exists. ID doesn’t say anything about the how because that comes only after design has been detected and studied (along with all relevant evidence)


      2. Once again Frank you invoke Behe like an oracle, repeating his position like a comforting mantra, while avoiding discussing the details (just as Behe had). In not even a single case of the claimed five irreducibly complex examples in “Darwin’s Black Box” had Behe actually nailed down his case (all five of them had unresolved issues regarding what exactly was going on, such as the exact nature of the flagellum motor proteins and cap system, a snag for Behe claiming that “Darwinism” ought to have accounted for systems that were not in fact resolved at the level of detail Behe’s anti-model required). Behe noted only in passing these caveats, but failed to account for any of them himself.


      3. Hi Joe! Still using the same “Frank Huggins” sockpuppet? What happened to “Sharon Mahoney”?

        Are you going to shitbomb this board too with your usual C&Ped Creationist idiocy? How long until we get “your side can’t explain eukaryotes!!!” in BOLD ALL CAPS screaming? 🙂


      4. There’s a JAndrew on Twitter who plays that prokaryote/eukaryote card (or at least used to, until I kept on challenging him to discuss the technical literature on those topics). Antievolutionists actually have very few cards to play, and “Origins or Bust” is the default mode for those who draw only from secondary wells, be it Michael Behe or Reasons to Believe or Answers in Genesis or Kent Hovind.


      5. Again, no one on this planet knows how to test the claim that blind and mindless processes produced any bacterial flagellum. And you don’t have a mechanism capable of producing eukaryotes. I would gladly go over the evidence. It definitely does NOT support blind and mindless processes.

        Yes, of course origins is key. If life was designed then it is a given they were designed with the ability to evolve and adapt. It is only if the OoL was via blind and mindless processes do we say the subsequent evolution was also blind and mindless.


      6. You’ve studied much on either topic, Frank? Flagella or eukaryote origins, or merely culled these examples from the ID literature you’ve drawn from? This is still an “Origins or Bust” slant, though, and leaves unaccounted for several billion years of life after eukaryotes and flagella appeared on the scene, which current evolutionary theory has shown itself quite adept at accounting for, and ID equally adept at not thinking much about it all (like that reptile-mammal transition case).

        And btw do you have any idea who the “Designer” supposedly was in any of these cases? Just the one, or a bunch of them over time? And are any of the putative designers currently doing any designing? Let’s try to nudge this matter closer to the present, instead of wallowing in the life events of billions of years ago (eukaryotes and flagella).


  3. As for “devolution” you can actually google the word. You may also remember the 1970’s and a band called “Devo”. The word refers to “evolutionary degeneration”


    1. “Devolution” is an archaic term last used in science in the 19th century. It was based on the long discredited idea evolution has an “upward” direction toward more advanced, “higher” creatures. Today it’s only used by ignorant Creationists and ID charlatans trying to push their bogus anti-science “design” ideas.


      1. Actually the context in which it is being used just means “evolutionary degeneration”. And that evolution doesn’t have a direction actually works against your position’s claims. Finally, seeing that design is very pervasive in science, only the ignorant would call it anti-science. Especially given the fact there aren’t any viable scientific alternatives to Intelligent Design.


      2. One does not speak of “alternatives” to fictions or pseudoscience. There is no Intelligent Design model, not at least so far. ID consists of merely antievolution, not a positive argument. And that is compounded by their failure to deal with most of the data (which process I measure at the source level in my TIP research). Someday perhaps advocates of Design will up their game to offer a clearer conception of what they think happened regarding the full data field, but based on their activities so far, I’m not holding my breath on that one.


      3. Whatever Joke. The fact is Behe is getting laughed at far and wide for his latest book attempt to con the mouth-breather IDiots. I bet you already sent money for your autographed copy. 😀


      4. Whatever, timmy. The fact that all you can do is get all belligerent sys it all. But thank you for proving evolution does not predict a nested hierarchy (it requires a direction of added traits).


      5. rjdownard- there isn’t any blind watchmaker evolutionary model. ID is NOT anti-evolution. ID argues that evolution proceeds by means of intelligent design and not blind and mindless processes. That is ID says organisms were intelligently designed to be able to evolve and adapt. And I presented the positive argument for ID.

        And it still stands that to refute ID all one has to do is step up and show blind and mindless processes can. And yet no one has any idea how to do so.

        You lose.


      6. Sorry, Frank, but evolutionary naturalism definitely is a model (in fact its way above that, having graduated by the rough and tumble of the last century and a half of work into a full scientific Theory, the only one on the block when it comes to the history of life), which I see on display in the vast technical work I keep track of in my research. Likewise I can observe the nothing that is ID, an approach that consists of “not Darwinism” but never getting close enough to the data field to spot that their non-articulated model is never going to account for it.

        Let us test that out. Please describe for us, if you were to travel back to observe a “design event”, what it would look like, in a specific example. And how would that look different from a purely natural evolutionary process generating the outcome in question.


  4. “Natural selection does not work as an engineer works. It works like a tinkerer — a tinkerer who does not know exactly what he is going to produce but uses whatever he finds around him… to produce some kind of workable object.”

    As a working design engineer for several years, with patents and awards, yada yada yada, I think this is an unfair statement–unfair to natural selection and the evolutionary algorithm in general. When an engineer has a problem that has been solved before and uses Roark, Marks Handbook, or some other references, he or she is acting analogously to a gene in biology; using a process that has been developed previously. When an engineer tries to do something new, they (he or she), there is no magic that tells them what to do. They have to tinker until they either give up or solve the problem (usually by combining some other existing parts in a new way). Typically this takes years with a lot of trials and errors.

    As far as I know, the process and history of engineering design has not been intensively studied, as biological evolution has. The few studies I have been aware of all show similarities to biological evolution. Some examples:

    Neils Bohr: an expert is “a person who has made all the mistakes that can be made in a very narrow field.” (i.e., the power of trial and error)

    Priscilla Long:

    “Imagination, suggests Princeton molecular biologist Lee M. Silver, is related to the brain’s “noise” (random firings of neurons, or nerve cells), thus generating more associations. Brain scans of people with schizophrenia and their unafflicted family members show mega-amounts of random noise. Brain scans of control subjects (no schizophrenia in the family) do not.

    A recent major study  confirmed a high association between people in creative professions and their first-degree relatives (parents, offspring, and siblings) who have psychopathologies such as schizophrenia. Could there be inherited brain structures that produce thought patterns such as “broad associative thinking” in which contradictory images and ideas knock about together, structures that serve an artist’s work but that in some brains go too far and become the twisted thoughts of mental illness? Does selection for a more robust imagination – so very useful to us humans – keep imagination’s more dysfunctional forms from dying out?”

    Franklin Delano Roosevelt, during the Great Depression:

    “The country needs and, unless I mistake its temper, the country demands bold, persistent experimentation. It is common sense to take a method and try it: If it fails, admit it frankly and try another. But above all, try something…”

    Gall’s Law — A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works and cannot be patched up to make it work. You have to start over with a working simple system.  – John Gall, Systemantics: How Systems Really Work and How They Fail (1975, p.71)

    Popper : “there is no such thing as instruction from without … We do not discover new facts or new effects by copying them, or by inferring them inductively from observation, or by any other method of instruction by the environment. We use, rather, the method of trial and the elimination of error.” [I think this depreciates observation in an unfortunate way, but refers strictly to the mental processes which assess observations.]

    “It took a specialised team of silicon designers to create the Hololens DSP, because designing chips is hard work, fraught with trial and error … “

    I have many more examples, and I haven’t even mentioned Thomas Edison. The data are out there: engineering design and scientific development are just rarefied forms of evolution. There is no magic involved. We have all seen technology evolve in our life times. (Sometimes it “devolves” also, but such examples do not survive and reproduce in the marketplace.)

    By the way, see the Szostak Lab website for a working model of an evolvable cell, produced from mixtures of chemicals by trial and error.


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