Is Convergent Evolution Explainable?

Creationists constantly repeat their fictitious “law” that evolution can’t create new “information,” and therefore all new features of organisms must have a supernatural source.

We’ve previously written about two specific instances of new features that arose from the familar mechanism of gene duplication, followed by mutation in one of the duplicates to perform a new function. See ICR: Full Blown Reality Denial, about how E. coli developed the ability to digest citrate, and see also How One Gene Becomes Two Different Genes, about how Antarctic eelpout developed the ability to survive in frigid waters.

Now we have another example, and it’s far more spectacular because it involves the same new feature occurring in several species. At the PhysOrg website we read: Far from random, evolution follows a predictable genetic pattern, researchers find. Here are some excerpts, with bold font added by us:

Evolution, often perceived as a series of random changes, might in fact be driven by a simple and repeated genetic solution to an environmental pressure that a broad range of species happen to share, according to new research.

Princeton University research published in the journal Science suggests that knowledge of a species’ genes — and how certain external conditions affect the proteins encoded by those genes — could be used to determine a predictable evolutionary pattern driven by outside factors. Scientists could then pinpoint how the diversity of adaptations seen in the natural world developed even in distantly related animals.

“Is evolution predictable? To a surprising extent the answer is yes,” said senior researcher Peter Andolfatto, an assistant professor in Princeton’s Department of Ecology and Evolutionary Biology and the Lewis-Sigler Institute for Integrative Genomics.

Wow — convergent evolution is not only explainable, it may be predictable! Here’s a link to the paper: Parallel Molecular Evolution in an Herbivore Community. We’ll continue with the PhysOrg article:

The researchers carried out a survey of DNA sequences from 29 distantly related insect species, the largest sample of organisms yet examined for a single evolutionary trait. Fourteen of these species have evolved a nearly identical characteristic due to one external influence — they feed on plants that produce cardenolides, a class of steroid-like cardiotoxins that are a natural defense for plants such as milkweed and dogbane.

Or, as the creationists would put it, the Designer — blessed be he! — swooped down and gave these unrelated insects the genetic “information” necessary to feed on cardenolides. Let’s read on:

Though separated by 300 million years of evolution, these diverse insects — which include beetles, butterflies and aphids — experienced changes to a key protein … . The protein in these insects eventually evolved a resistance to cardenolides, which usually cripple the protein’s ability to “pump” potassium into cells and excess sodium out.

That ol’ designer must have been really hopping around to get all that done. We continue:

“The finding of parallel evolution in not two, but numerous herbivorous insects increases the significance of the study because such frequent parallelism is extremely unlikely to have happened simply by chance,” said Zhang [Jianzhi Zhang, a University of Michigan professor of ecology and evolutionary biology], who is familiar with the study but had no role in it.

If it’s unlikely to have happened by chance, you know what the creationists will be thinking. They’ll be screaming Oogity Boogity! as loud as they can. But perhaps there’s a rational explanation. Here’s more:

“It shows that a common molecular mechanism is used by many different insects to defend themselves against the toxins in their food, suggesting that perhaps the number of potential mechanisms for achieving this goal is very limited,” he [Zhang] said.

Moving along:

The researchers found that the genes of cardenolide-resistant insects incorporated various mutations that allowed it to resist the toxin. During the evolutionary timeframe examined, the sodium-potassium pump of insects feeding on dogbane and milkweed underwent 33 mutations at sites known to affect sensitivity to cardenolides. These mutations often involved similar or identical amino-acid changes that reduced susceptibility to the toxin. On the other hand, the sodium-potassium pump mutated just once in insects that do not feed on these plants.

They all had the same thirty-three mutations? The creationists will be screaming “irreducible complexity!” But wait — hold on — there’s a mechanism:

Significantly, the researchers found that multiple gene duplications occurred in the ancestors of several of the resistant species. These insects essentially wound up with one conventional sodium-potassium pump protein and one “experimental” version, Andolfatto said.

[…]

“These gene duplications are an elegant solution to the problem of adapting to environmental changes,” Andolfatto said. “In species with these duplicates, the organism is free to experiment with one copy while keeping the other constant, avoiding the risk that the new version of the protein will not perform its primary job as well.”

Aha! Just as in the other cases to which we linked, when you’ve got an extra gene to play with, it can mutate and thus provide new “information.” And random mutation can blunder into the same solution again and again. Well, that’s the explanation. One last excerpt:

“The power of what we’ve done is to survey diverse organisms facing a similar problem and find striking evidence for a limited number of possible solutions,” he [Andolfatto] said. “The fact that many of these solutions are used over and over again by completely unrelated species suggests that the evolutionary path is repeatable and predictable.”

Okay, that’s very nice, but what’s the creationist reaction? We’ve got one for you. It’s from the Institute for Creation Research (ICR). If you don’t know who they are, you can read about them in the Cast of Characters section of our Intro page. Their article is How Some Insects Can Eat Poisonous Plants.

We’ll skip their description of what the scientists did, because you already know that. All we care about is how they dismiss the science and cling to their mythology. Here we go, with bold font added by us:

Convergent evolution is conceivable, but it is scientifically meaningless unless researchers can actually detect it. Otherwise, to claim convergent evolution as these authors did is merely to beg the question of convergent evolution. In other words, the study authors ignored all non-evolutionary explanations for how these remarkably specific DNA differences arose.

Oh, we hadn’t noticed that. Yes, the biologists ignored “non-evolutionary explanations.” What might they be? You’ll see. On with ICR’s article:

Perhaps the DNA differences were directly created, or perhaps well-designed cellular systems put them in place at some point after creation.

Hey, those are two hot possibilities! Why don’t the creation scientists get to work researching them? They have their reasons. Behold:

The first possibility is blind to scientific experiment, which cannot directly investigate the past. No scientific experiment has verified the second possibility, but no experiment showed that these systems arose by convergent evolution either.

Satisfied? And now we come to the end:

These researchers conducted a rigorous study, to their credit. However, there was no scientific reason for them to have excluded origins possibilities that are at least equally valid.

So there you are. Teach the controversy!

Copyright © 2012. The Sensuous Curmudgeon. All rights reserved.

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35 responses to “Is Convergent Evolution Explainable?

  1. By demonstrating a workable natural process to explain convergent evolution, scientists showed that no supernatural process was necessary. They didn’t consider it, true, but they didn’t need to.

    It’s one less gap to be filled by ICR’s god.

  2. Another finger in the dike leaking ignorance into the village. Yay.

  3. For an experiment to include any element of mysticism, all elements of mysticism must be included. What if data is actually more enjoyable while Buddha is smiling? What reason is there to starve their suggested control by excluding deities and minions that other cultures have believed in? The goal is after all, an objective point of view.

  4. Ceteris Paribus

    @Dean: Thanks for reminding me of the power of The Flying Spaghetti Monster [aka FSM], which during a Kansas State school board investigation a few years ago, was introduced as a viable supernatural alternative to the evils of Darwin.

  5. I am wondering who will jump on the dike comment above. first…….

  6. ICR screed protest that the PNAS scientists

    ignored all non-evolutionary explanations for how these remarkably specific DNA differences arose

    And let’s face, that is a shocking omission on part of the scientists — as bad as consulting a doctor, about a pain in the lower back, who failed to enquire if one had any enemies who are skilled in the dark arts of voodoo…

  7. While you evolutionists have been claiming all along that the path of evolution is not predictable, this research has shown the evolutionist claim to be false. Another failure of evolutionism, I say.

  8. Christine Janis,

    @Tom.
    The overall outcome of evolution in the long term is not precisely predictable. However, some of the mechanisms may be. For example, all mammals that return to the sea evolve a similar suite of adaptations to cope with living underwater. Here they have shown that the same suite of molecular mechanisms may be enacted to solve the same biochemical problem. But they can’t predict exactly which animals may or may not evolve this in the future.

    Should the world heat up the way it is projected to, we know plenty of what has happened to animal populations in other times of global warming to be able to make some general predictions to what will happen where in the world (although the precise outcome is subject to stochastic influences and can’t be predicted)

    Meanwhile, your comment just reflects the usual creationists’ view of evolutionary biology.

    Evolutionary biologists find something new

    Thus what they knew before wasn’t 100% correct

    Thus they have proven evolution wrong.

    Err — that’s it.

  9. Ceteris Paribus

    But maybe the scientists are proving that evolution will converge on the production of a beast which looks like a leopard, but has the mouth of a lion and the feet of a bear, and features seven heads with ten horns each, and converses with a talking dragon? Sure beats a mere Croc-a-duck

  10. @TomS:
    While you evolutionists have been claiming all along that the path of evolution is not predictable, this research has shown the evolutionist claim to be false. Another failure of evolutionism, I say.

    Well, you don’t know squat about debates about convergent evolution, but you use this as an excuse to invoke Creationist Argument #13. (I’ve seen all the creationist arguments, so I numbered them.)

    Creationist Argument #13 “Learned Something New”: If scientists observe something they didn’t expect, that shows they know nothing about about anything. If scientists observe something they did expect, that shows they’ll stop at nothing to prop up their atheist dogma.

    I know there’s no point getting technical with witch-doctors, but the number of possible solutions to a problem is going to vary from one gene to the next. In some genes, there may be a couple dozen ways of getting the same functional change, in other genes there may be two or three or (I suppose one– though I’ve never seen it) ways of getting the same functional change. For complex multigenic features, the number of ways of solving a problem may be astronomical. Evolution can also “look” convergent on the outside (like the fusiform shape of dolphins vs. ichthyosaurs) but be divergent at the genetic level.

    Funny how the known examples of convergent evolution at the genetic level are within the limits of population genetic estimates.

  11. @Ed:
    “They had no need of that hypothesis.”

    @Megalonyx:
    Good one!

  12. Hey, guys, ease up a little. Consider that I may have been joking.

  13. Christine Janis,

    OK, Tom. But maybe we can get Diogenes to post his Creationist Arguments #s1-12!

  14. Ok, here is a real question that I have been pondering after reading this study. Did the majority of the species start to mutate together to develop this trait or did it occur in one or a few individuals and then quickly spread and get fixed?

  15. Here is another thought that I believe has merit, consider psuedogenes or sometimes called broken genes, we have all these sections of dna inside us as do other species. Now encode has discovered that most of this dna, though it doesn’t code for a protein, it performs regulating tasks and is functioning. One of these genes in particular is thought to be a gene that used to synthesize vitamin C, but it’s now broken and doesn’t work, so we can’t synthesize vitamin C and must get it from our diet. I realize there’s no way to test this but let me suggest anyway, what if some of these genes are there for use if we need them in the future. Let’s say there is extreme famine and we do not have access to fruits and vegetables and are not able to get the vitamin C we need, maybe then, this gene will turn on and we will survive that crisis. Another thing that makes me wonder why this is considered a broken gene is because we don’t currently need it. How many people are presently suffering from scurvy for lack of vitamin C, likewise how many apes that have this broken gene are suffering from vitamin C deficiency. I don’t have the statistics but would venture a guess of slim to none. So if we can easily get the amount of C we need then why is this considered broken, instead of maybe turned off. The insect study is a perfect example of those that needed it had it turned on and those that didn’t, may in the future need it or not. Here is a good question to test this, if the other insects had randomly mutated to develop poison resistance but not need it, is there any reason that trait would be selected against and not remain, even if not used. These are questions, so if there is evidence to answer them, I welcome it.

  16. Lisa O says: “I realize there’s no way to test this but let me suggest anyway, what if some of these genes are there for use if we need them in the future.”

    As you say, your idea that those genes were providentially placed where they’d be needed one day is untestable, so it’s not science. There may be rare individuals in which those are functioning genes, which, under normal circumstances, is irrelevant to their survival, However, if the environment changes in a way to make that gene essential, they’re the ones that will survive and reproduce. If there are no mutated individuals with those genes, the species goes extinct. That’s how it works.

  17. “There may be rare individuals in which those are functioning genes, which, under normal circumstances, is irrelevant to their survival.”

    That’s what I was wondering, if there are only a few predictable, repeated, mutations available and this trait does not hurt the reproductivity or survival rate, then wouldn’t we see quite a few insect species who have developed this trait even though they don’t need it. Why do we see it only in the species that are using it as if it were turned on and in the other species there is only one mutation in that same gene, compared to 33 in the species that developed the trait. I’m saying there must be a reason that there isn’t a more similar number of mutations or some species that have the trait and don’t need or use it, but we don’t see either of those things. So, in your example above, all these species developed the poison resistance before they needed it and in other examples an already existing trait will allow a species to avoid extinction, so we should see other insects that evolved this trait and don’t need it, do we see this, the study says 1 mutation verses 33.

  18. Ceteris Paribus

    @Lisa: The PhysOrg article referenced is much less than clear about that 1 mutation vs 33 mutations which puzzles you. It appears that 29 “distantly related” species of bugs were studied. In 14 species which dined on milkweed or dogbane, a total of 33 DNA sites were found which produced essentially similar mutations which then allowed the bugs to tolerate the poison in the plants. In the other species which did not dine on the poison plants, only 1 mutation in the relevant DNA sites was found, meaning it was kind of a random event not related to adaptation.

    So basically the article is just saying that the bugs that didn’t have any need to eat the poison didn’t evolve a defense against the poison. But the bugs that did evolve a defense against the poison were able to eat the plants which other bugs could not, and so provided them with the advantage of a food source which other insects left unused. Which is what adaptive advantage is all about.

    So the real question is, is it a big deal that these 14 distantly related insects all found mostly pretty similar ways to avoid the poison problem? Probably not, if you consider that distantly related water animals such as dolphins, sharks, and extinct reptile ichthyosaurs all evolved very similar body shapes to allow swimming in oceans at high speeds. The unrelated insects all had the same chemistry problem to solve, so their genetic solutions were of course quite similar.

    (The PhysOrg article cited appears to be merely a very poorly written press release from Princeton University – note that it says:
    Though separated by 300 million years [emphasis added] of evolution, these diverse insects—which include beetles, butterflies and aphids—experienced changes to a key protein called sodium-potassium adenosine triphosphatase, or the sodium-potassium pump, which regulates a cell’s crucial sodium-to-potassium ratio.”

    And: “During the evolutionary time frame examined [emphasis added], the sodium-potassium pump of insects feeding on dogbane and milkweed underwent 33 mutations at sites known to affect sensitivity to cardenolides.”

    But flowering plants, such as dogbane and milkweed, did not even exist until about 140 million years ago.

    The misuse of “convergent evolution” as a strawman argument in the ICR article is also inexcusable, but probably the best the ICR can do.)

  19. I’m new here so I’m not sure what ICR stands for, also these are my own comments, ponderings and questions, I am not affiliated with any group, nor do I read and repeat other people’s comments or arguements, if my comments resemble something you’ve heard before, rest assured it is pure coincidence and not conspiracy. You point out that it says these species are seperated by 300 million years of evolution, I do believe that means when they diverged from their common ancestor, not when they actually developed the poison resistant trait as you are implying. So in 300 million years the other insects only had 1 mutation, where as the ones who developed the trait had 33, I say that’s important, you say, no, none of this matters, this article was poorly written. I will continue to learn from the interesting new studies and information we are learning about dna and evolution, and you can continue to study fruit flies, learn nothing new and be left behind, to each their own.

  20. Christine Janis,

    “and you can continue to study fruit flies, learn nothing new and be left behind”

    Sorry, dear, that little comment tags you as someone who disparages real science.

  21. So the only real science is to continue studying something that prevents comprehensive views and understanding of how evolution works on a real world scale, shouldn’t everyone disparage that? Don’t be sorry, I’m sure not.

  22. And just to be clear, are you saying that this study is not real science? It was conducted using scientific methods. I am simply professing my preference of type of study, one which actually shows us something verses one that as these scientists actually claim could never give us any comprehensive results. I have long felt that these fruit fly studies are a waste of time and money and only serve to keep certain biologists in a job and do nothing to further our understanding of evolution, which this study only confirms. Maybe at first there was something to be learned but that deal is played out and I for one am excited and ready to see what these new comprehensive studies are going to teach us, maybe you are not so much, if that’s “real” science, then I would do best to avoid it, thanks for the warning.

  23. Lisa O says: “I for one am excited and ready to see what these new comprehensive studies are going to teach us, maybe you are not so much, if that’s “real” science, then I would do best to avoid it, thanks for the warning.”

    *Sigh* It always starts with an innocent-seeming comment or two, and then the mask falls away and it swiftly degenerates. Sorry, Lisa, but since you’re trying to incite a flame war with Christine Janis, I’ll have to put a stop to this. She definitely knows what science is, and that’s what we’re all about here. This isn’t the blog for you.

  24. Ceteris Paribus

    @Lisa: The “real” science you seek is done by real scientists who use a specialized vocabulary to communicate their newly found knowledge with other scientists who are working in the same or related fields.

    But, general readers such as we do not have the training and ability to understand the precise language used by scientists. So instead we have to rely on summaries and news articles available to us on line or books or magazines.

    Some summaries are well meaning, but poorly written such as the Princeton University press release, which was unfortunately reprinted without comment in the PhysOrg journal that was referenced in the original post.
    This communication problem will always exist for as long as universities turn out many more journalism majors than science majors.

    Only a very few real scientists make time to publish books or articles which are intended for a general audience. In the field of evolutionary biology, you could start by looking for books and articles written by Jerry Coyne who does not have a theistic view of evolution; or Ken Miller, who does have a theistic view.

    Still other summaries or books are written by proselytizing organizations such as the ICR – which are the initials of the Institute for Creation Research. Beware of the ICR articles because the ICR sees no moral problem with mis-using scientific reports if they can take just bits and pieces of what the scientists publish in order to make their own ICR article support something that the ICR has already decided must be true because of their religious views. That is not the way science works.

    Just practice questioning any easy answers to complex questions, and you will do fine. Good luck.

  25. Though I agree, this is not the blog for me and will leave you all to it, I would also like to make the point that I did not incite a war with Christine, I was only defending my opinion against her assault, it seems everytime someone wants to challenge me, they get offended when I don’t just lay down and say, oh, you’re right please walk right over me, my thought and opinions, these are valid opinions and I was searching for comments on this particular study and line of study, I am disappointed that none of you scientists are discussing this in an intellectual, informative way, I’m not sure there is a “blog” for me because everywhere all I get is ignorant people arguing against each other’s empty chairs instead of looking for real answers. I will plague you no more.

  26. Lisa O said:

    I am disappointed that none of you scientists are discussing this in an intellectual, informative way,

    You keep using that word “intellectual”. I do not think it means what you think it means.
    Yes, you need a different blog. Based on your posts on other pro-science sites (e.g. Why Evolution is True), it sounds as if you should start your own. That way, you can post all you want about how God and aliens created everything in “an intellectual, informative way”.

  27. If you want me to go away, why do you keep replying to me, there were people on WEIT who wanted to discuss that with me but Jerry wouldn’t let us and so I haven’t mentioned it again, I’m not saying they agreed with me, but it was a respectful exchange, that is not what I’m referring to with challenging, I expect people to challenge that, though I do have very much to say on it, I should start my own blog. The challenging I’m talking about is when discussing scientific studies and questions, I believe it is very common and not all bad that we challenge each other but when I try to debate on the defense, I get shut down, everyone else can do it but you don’t want an opposing view to fight back. If you would notice the other comments I’ve made on WEIT is very on topic. The real argument here would be what recent contributions have fruit fly studies made to science, and what things are remaining undiscovered because of the narrow view this fly species is keeping science in tunnel vision. This would be arguing in what I consider an intellectual way, instead of just saying yeah, those creationists are really dumb aren’t they. I’m not trying defend their science, I’m challenging yours, it has nothing to do with them. If you have a valid argument to show how we have anything new to learn from fruit flies, I would love to hear it, my argument for.the.opposing point of view is this study.

  28. I’m not sure there is a “blog” for me because everywhere all I get is ignorant people arguing against each other’s empty chairs instead of looking for real answers. I will plague you no more.

    Whew, that’s a relief! For a minute there I thought someone actually expected us to engage in intellectual conversation. Now we can get back to our worship of false science, and depraved swilling of spirit-based entities.

  29. Your IP number keeps changing, Lisa O. Not a problem. We have other ways to say goodbye.

  30. … but when I try to debate on the defense, I get shut down, …

    Somehow that does not surprise me in the least. Consider the possibility that the cause of the problem does not lie with other people, but in yourself.

  31. Ceteris Paribus

    -30-

  32. Once the DI actually performs a controlled study of something tangible, the intellectual debate can begin. Until that day comes, creationists have no valid context to use the word “science” within.

  33. Lisa O, now that you’re banned, the only thing you’ll be able to do is listen. So listen up: Everything you’re talking about has already been covered a thousand times over. Science is about evidence and logic. You keep trying to force fit selected pieces of evidence into your “worldview”. That’s not how it works. Years ago, during discussions on whether the Big Bang theory effectively explained the evidence, one scientist came up with the hypothesis that the reason that light was being shifted in wavelength from other stars was due to it being “tired”. No kidding. It was called the “tired light theory”. The idea was that the light lost energy as it propagated. Energy and wavelength of electromagnetic waves are inversely related. The less the energy, the longer the wavelength. The problem was that it explained one part of the evidence (the light was shifted) but not all of it (How about the light that was shifted up, meaning it had more energy?). Guess what? It was thrown out. That’s how science works. Based on everything you’ve written, you keep trying to find the juiciest bits of evidence to fit your “Genesis” account of history. It doesn’t work that way. You don’t start with a conclusion and then fit the evidence to it; it works the other way. You develop a theory based on all of the evidence. And pretty much everyone on this blog has heard or read everything you’re spouting. Further, we’ve heard it better. If you’re really going to go with this crusade of yours, check out Lee Bowman or a commenter named “FL” on Panda’s Thumb. They can spout nonsense and make it sound perfectly reasonable. At first. The problem is that, as Tomato Addict and Dean pointed out, you’re going to find your “arguments” shut down pretty quick. Scientists actually like to talk about science, not non-sense (unless they enjoy the occasional episode of the Kardashians or “Jersey Shore”).

  34. Scientists actually like to talk about science, not non-sense (unless they enjoy the occasional episode of the Kardashians or “Jersey Shore”).

    Or even, {dramatic chord} Monty Python!