A Good Idea Gone Bad? Part I

Earlier today, I posted a little rant about mischaracterizations of evolution, but I did little to set out exactly what my thoughts are on the matter. As requested, below is an attempt to do so. It’s still rough and needs editing, but I’ll put it out for y’all to chew on.

Part I: Introduction, and Why (Micro)Evolution is Good Science

Part II: What Molecular Biology Tells Us about Macroevolution, and How This is Compatible with Orthodox Christianity

The modern world is not evil; in some ways the modern world is far too good. It is full of wild and wasted virtues. When a religious scheme is shattered (as Christianity was shattered at the Reformation), it is not merely the vices that are let loose. The vices are, indeed, let loose, and they wander and do damage. But the virtues are let loose also; and the virtues wander more wildly, and the virtues do more terrible damage. The modern world is full of the old Christian virtues gone mad. The virtues have gone mad because they have been isolated from each other and are wandering alone. Thus some scientists care for truth; and their truth is pitiless.

– GK Chesterton, Orthodoxy

Chesterton, as usual, was both correct and a bit ahead of his time. Some scientists, indeed most, care for truth above all–hard, empirical, incontrovertible truth. They search for all-encompassing theories to explain everything they see; they constantly search to simplify, to reduce, to explain with fewer and fewer terms. But this virtue–truthfulness–is divorced from any other, and for most of my co-workers, truth has been reduced to only the tangible. The problem with modern science is not in its search for material truths, nor even in its self-limitation to material things, but in its declaration that nothing else matters, or even exists.

Evolution is the example nonpareil of this unfortunate tendency. By itself, it is an admirable thing: a theory that seeks to explain in material terms how material life came to be. When looked at from a molecular level, it makes compelling sense. Because of the chemical structure of DNA, how it is reproduced, and how it interacts with the environment around us, errors happen, all the time. While the overwhelming majority of these errors are either detrimental or cause no harm, it is certainly possible for an “error” to be beneficial.

It is often quoted by folks who are against “evolution” that there is no evidence for “beneficial mutations.” But, this is simply not true, at least not for unicellular organisms and viruses. Take, for example, any number of bacteria that cause human infection. These organisms, because of their rapid growth (some go through generations every 20-30 mins), have thousands of generations in the time it takes us humans to go through one. Mutations are generated more quickly, and are perpetuated more readily if they are beneficial. We have been treating our sick with antibiotics for the past 60+ years now, and the bacteria have responded by “selecting” for mutant forms of the targets of the antibiotics, or getting around the antibiotics in some other way. Some antibiotics target the bacteria’s protein manufacturing machinery; resistant bacteria develop because they change the machinery so that the antibiotic no longer sticks to it. Other antibiotics, like penicillin, cause defects in the bacterial cell wall, but resistant bacteria co-opt an existing enzyme to chop the antibiotic up. There are countless examples. In unicellular, quick-reproducing organisms, there is no doubt that evolution happens. Not even most “intelligent design” advocates would dispute that. “Microevolution,” they say, is a fact of nature.

Before I get to the vastly more controversial topic of “macroevolution,” there is another type of “microevolution” that may not often be thought of as such, and that is cancer. Within our bodies, our cells have to act in concert in order to maintain proper bodily function; but, sometimes, a cell gains a “selective advantage” over its neighbors, through an increase in growth rate, or an inability to die when expected. These “advantages” lead to overgrowth, better known as a tumor, and qualitatively, there is no difference between the changes that have happened to a cancerous human cell and those that happen to bacteria. Both confer a cellular advantage; the difference is that the cancer cell is confined within a larger multicellular organism, and its proliferation is inevitably to the detriment of the organism as a whole. Most of the time, the changes that result in cancer are genetic ones, either inherited from our parents or produced by environmental or random DNA damage. Those are the same mechanisms that happen in “microevolution.”

So, the biochemical processes that lead to microevolution of bacteria also produce cancer. The same DNA replication and repair also goes on in normal human and animal cells. Why can they not also change in a way to produce evolutionary changes? Of course, there are several reasons why any such changes would be both much slower and more difficult to come by. First, because of our much slower generation times, and the changes have to be in the cells that pass down genetic material from generation to generation (germ cells/sperm/eggs), any changes will be hard to either produce or observe. But, I think that is only part of the story. The far more important reason why “macroevolutionary” changes are so scarce is that any change must result in an increased fitness for the organism as a whole, not just a single cell. Cancer is not macroevolution. But, these mutations leading to increased organismal fitness are not impossible, just rare. Over a very long time scale, they become likely.

The problem with this scenario, however, is that long time scales are inimical to experimental science. Macroevolutionary biology, as a result, becomes largely a historical field. We’re reduced to looking at things like the fossil record, which admittedly is open to a multitude of different interpretations (as is a lot of history). I frankly do not know enough about paleontology to make an argument either way, for or against evolution. But we can also do things like comparative genomics, where we look at the DNA of different organisms and see how they differ. In the next episode, I’ll deal with how comparative genomics and related fields can give us a handle on “macroevolution,” and try to come to some rough conclusions.


8 Responses to “A Good Idea Gone Bad? Part I”

  1. 1 Theocoid August 9, 2006 at 10:42 am

    I’m looking forward to the rest of your discussion.

  2. 2 Cheesehead October 19, 2006 at 8:19 pm

    Hi Ed,

    I have enjoyed our discussion over at WOF’s blog. You and Mr. Wonders are both intelligent and polite debaters. It sounds like he does not want to get into the scientific end of things over on his blog, so this looks like as good a starting point for the science portion of our discussion as any. I had a few ideas about how to try to frame our debate, but your first post here and the two which are promised to follow will do just fine as a springboard.

    Let’s start with the structure of DNA and how it is reproduced. This marks a high hurdle for evolutionary theory right off the bat. Where the heck did this stuff come from? The thermodynamics of the molecular structure of DNA militate against it arising spontaneously, and this is borne out by the fact that no actual experiments have been carried out which result in self-replicating proteins, let alone DNA using any remotely plausible primordial soup or atmosphere. When I say actual experiments I exclude computer models because of the virtually infinite array of interventions which can be subtly or even unwittingly woven into the model which make the model work but which would not happen in the real world.

    Next off is the inference to design inherent in DNA. When you read this post you will likely conclude that you and I speak the same language and that I intended to convey specific information in this long series of characters comprised of twenty-six letters, spaces, and several punctuation marks. You will also probably conclude that a human composed this string of characters, or at least that a human-designed computer programmed to spew forth creationist propaganda delivered this “message” to your blog. So it is with DNA. It encodes functionally specified complex information. The nature of the information is tied to the structure of the DNA but is not an inherent property of the molecule. IOW, in all cases except biology when we see functionally specified complex information we attribute it to design, not “lucky noise”. Why should biology be any different?

    Regarding “beneficial” vs. “neutral” or “harmful” mutations, this really mischaracterizes the terms of the debate (and is done by folks on both sides of the issue). The degree to which a mutation can be said to be beneficial is entirely dependent on the circumstances of the bearer of that mutation. If it conveys a survival advantage it is beneficial. If it hampers survival it is harmful. If this sounds like a tautology, it’s because it is. 😉 Here’s the rub–a “beneficial” mutation in one environment becomes “harmful” in another. A perfect example of this is sickle cell anemia. In the presence of frequent outbreaks of malaria it is “beneficial”. Absent malaria it is definitely “harmful”.

    This ties in well with drug-resistant bacteria. The mutations which cause them to become drug resistant are beneficial as long as the drug in question is in use where they are. However, these mutations are almost invariably accomplished by loss of genetic information. The resistant cells lose the ability to transport some molecules through their membranes or give up some metabolic pathway which renders them resistant to the antibiotic in question. However, remove the antibiotic in question and the resistant cells will eventually be overgrown by more fit cells which code for the molecular transport or metabolic pathway which confers a competitive advantage in the absence of the antibiotic. Reintroduce the antibiotic and the population will again shift to favor the cells which under other circumstances would be considered impaired. This is why “superbugs” resistant to multiple antibiotics have not left hospitals and rampaged through the population as a whole. The mutation is not beneficial under any and all circumstances.

    Of course the example of cancer you present is much more in keeping with the effects of mutations on multicellular organisms. There are very few mutations (in fact none that I can think of) which could be said to be beneficial in any and all circumstances. Instead mutations result in corruption of genetic code or outright loss of portions of it.

    The key issue in all of this to my thinking is that in order for mutation to be an engine of evolution, we need to find mutations which result in previously uncoded for functionally specific complex information. IOW the mutations need to result in an increase in genetic coding which results in new metabolic pathways or new organism functions. I submit that this does not happen. Furthermore even if it did happen this is not sufficient to demonstrate the plausibility of evolution. We would also need to be able to observe these increases in usable genetic code accumulate within a population to the point that we could observe macroscopic changes (as opposed to minor adaptations to environment) that moves unicellular organisms into multicellular organisms with specialization of cells within the organism, or in multicellular organisms having new populations emerge which cannot be bred back with the organisms from which they were derived. These sorts of experiments have been done with bacteria and fruit flies, etc. and the result has always been the same–no success. IOW environmental adaptations accomplished by activating and expressing previously unexpressed traits which are coded for in DNA, or mutation by loss of membrane transport ability or loss of metabolic pathway, or by picking up previously existing genetic code through such things as plasmid transfer do not constitute evolution. They constitute adaptation, and no amount of adaptation by this means will result in more complex organisms unable to breed with their simpler ancestors but able to breed with each other. That would require the formation of new gentic code which specifies new functions, and we have no empirical data to demonstrate the possibility of this occuring spontaneously (i.e. without intelligent design and intervention).

  3. 3 Edmund C. October 19, 2006 at 8:34 pm

    Hey Cheesehead,

    Welcome! We do indeed speak the same language, and I agree with you much more than you may think 😉

    It may take me a few days to get back to you, but I think there’s enough fodder for a very long discussion in what you’ve written.

  4. 4 Edmund C. October 19, 2006 at 8:35 pm

    And that will force me to complete the series that I abandoned when I shut down the blog back the first of September…

  5. 5 Cheesehead October 19, 2006 at 9:56 pm

    Wow!! Who knew I was so powerful and influential? Now if only I could harness that power and influence into either more money or less work…

  6. 6 Edmund C. October 25, 2006 at 9:13 pm

    I haven’t forgotten about this…just been way too busy to give it the thought it deserves.

  7. 7 Cheesehead October 26, 2006 at 7:05 pm

    Standing by.

  8. 8 Cheesehead December 5, 2006 at 9:51 pm

    Drop me an e-mail if you ever get around to addressing this.

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