Science Corner: Seeing Red

Tigre d'Asie à robe blanche

Are fangs like these central to your concept of evolution? Photo by Céréales Killer

The X-Men character Cyclops has to wear ruby quartz glasses at all times to control his mutant power; consequently, his whole world is tinted red. Lately, I’ve been wondering if he isn’t alone in that respect; maybe a lot of people see the world tinted red, as in ‘nature, red in tooth and claw.’

Take this report on the genetics of why some fruit flies have more predictable behavior than others. The research itself seems sound and has intriguing implications. The discussion of possible evolutionary pathways then goes immediately to selection via predator-prey dynamics based solely on speculation. Maybe it’s confirmation bias, but I’ve noticed the same narrow take evolution, particularly in popular science domains like TED talks. Science fiction often follows suit; for example, X-Men comics and films often discuss evolution as if it is all about selection within direct, violent encounters.

Yet the picture evolutionary biologists are painting is much more complex. The variety we see in organisms can sometimes be explained by neutral drift or other mechanisms that don’t involve selection at all. And even when there is selection, it needn’t involve direct physical confrontation or predation. I can’t help but wonder if evolutionary biology would be more palatable to some if it weren’t so strongly linked to images of bloody violence and death.

Why the emphasis on predator-prey dynamics then? It’s a compelling pattern, and we humans love our patterns (a tendency which, of course, is often explained as an adaptation to avoid being eaten by predators). It provides a simple, compact explanation which is easy to comprehend and repeat, giving it a fitness advantage in the world of ideas — a world, it should be noted, where there is no violence or death and yet selection still occurs. And, as yesterday’s post on expectations suggests, once you start looking for the predation pattern, it can be hard to not see it.

When you think about evolution, do you immediately picture predators and prey?

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drandrewwalsh@gmail.com'

Andy Walsh

Andy has worn many hats in his life. He knows this is a dreadfully clichéd notion, but since it is also literally true he uses it anyway. Among his current metaphorical hats: husband of one wife, father of two elementary school students, reader of science fiction and science fact, enthusiast of contemporary symphonic music, and chief science officer. Previous metaphorical hats include: comp bio postdoc, molecular biology grad student, InterVarsity chapter president (that one came with a literal hat), music store clerk, house painter, and mosquito trapper. Among his more unique literal hats: British bobby, captain's hats (of varying levels of authenticity) of several specific vessels, a deerstalker from 221B Baker St, and a railroad engineer's cap. His monthly Science in Review is drawn from his weekly Science Corner posts -- Wednesdays, 8am (Eastern) on the Emerging Scholars Network Blog.

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5 Comments

  • Gerald Rau commented on May 20, 2015 Reply

    As a challenge to evolution, neutral drift is actually old hat (pardon the reference to your hobby). More specific to your question are theories that emphasize the cooperative nature of many species, such as kinship selection, and the Extended Evolutionary Synthesis, which claims there are many other factors that are at least as important in evolution as natural selection, including developmental bias, plasticity, niche construction, and extra-genetic inheritance (see http://www.nature.com/news/does-evolutionary-theory-need-a-rethink-1.16080). But I do think that part of the reason many Christians oppose evolution is the view that ‘God would not work that way,’ in reference to the common view of evolution as ‘nature red in tooth and claw.’ And maybe he did not – because that is not really the way evolution works, or at least not its most important cause.

    • drandrewwalsh@gmail.com'
      Andy Walsh commented on May 20, 2015 Reply

      True, neutral drift is old hat. The extent of its role still seems to be debated, but I gather it is fairly well accepted as having some place within evolutionary biology. In fact, as I read that Nature piece, all of the factors you listed are widely accepted within evolutionary biology. The discussion is about whether they are different enough to warrant rebranding the present model or not; there seemed to be little or no dispute about whether those mechanisms can and have contributed to biological diversity.

      But awareness of all that complexity is largely within the evolutionary biology community. That never gets to the general public. And what struck me about the fruit fly story (ostensibly my news item of the week) is that perhaps the complexity of contemporary evolutionary biology hasn’t even really reached the wider biology community. In my own experience, I had 9 years of undergraduate and graduate education in biology and never once learned anything about evolution; it wasn’t until I did a postdoc in computer science that I was formally introduced to it. Perhaps other biologists have similar experiences, which is why they fall back to just-so stories involving predators and prey when it comes time to speculate on the evolutionary history of whatever aspect of biology they are studying. In the fruit fly story, it’s completely unnecessary; we don’t invoke predator-prey dynamics to explain variability in genomes (mutations), so why is it necessary to explain variability in behavior?

      Or take the story of how humans came to prefer explanation involve agency that so many, including arch-skeptic Michael Shermer, love to retell. Assuming the rustle in the grass is a predator will keep you alive, so that kind of assumption was selected for, or so the story goes. Now, that’s certainly a plausible story. But as far as I am aware, we have no way of knowing whether any of that actually happened. Maybe that particular cognitive bias is a by-product of some more fundamental aspect of sensory integration — maybe binocular vision works better if there is a bias towards assuming that two very similar objects in the two different visual fields are actually the same object, for example. Or maybe it’s just neutral drift. But neutral drift doesn’t have a pattern, and doesn’t involve any agents, and so our cognitive biases steer us toward narratives involving the familiar pattern and agents of predators and prey. Now, if we actually have data the strongly supports the predator-in-the-grass scenario, then fair enough. But if not, and if we want more people to accept evolutionary biology as a central part of natural history, maybe we should try something like the binocular vision version.

      • Gerald Rau commented on May 21, 2015 Reply

        Wow, I am amazed that you got through that much biology without evolution. Having placed out of the intro course with AP, as a freshman I took a required semester course on it (a course which destroyed my faith in recent creation and almost my faith in God). Evolution is also the golden thread running through every intro textbook I have seen, and popped up many other places as well.
        On the other hand, I think you are right that few outside evolutionary biology understand much beyond natural selection and the Modern Synthesis. The article on fruit flies keeps coming back to genes – even the tab title is ‘Individuality may be a genetic trait’ – ignoring all the other possibilities, which is exactly the point the proponents of EES are making, that there is a need to extend the Synthesis (and implicitly to make the extension part of first year textbooks) so all biologists have at least a rudimentary understanding of other options well-accepted within their specialties, but largely unknown outside of them. For example, both plasticity and extra-genetic inheritance could be possible explanations for the fruit fly data, but the scientists involved do not seem to be examining those options, only looking for a gene, in spite of the fact that they are working with inbred lines that are supposedly genetically identical (which is probably not true either, as just about every organism tested has shown to be a chimera, with developmentally induced mutations present in some body cells). And natural selection leads naturally to a competitive predator/prey mentality, even though some of the others (niche construction and some aspects of extra-genetic inheritance, in particular) are very much based on a cooperative framework.

  • kennethdlitwak@gmail.com'
    Ken Litwak commented on June 17, 2015 Reply

    I can’t speak for the motivations of scientists in a discipline I know precious little about, but what you have described reminds me of the quip, “If all you have is a hammer, everything starts to look like a nail.” Having one particular explanation that can be pulled out and used every time, in spite of a lack of evidence to prove that, is common in all manner of human reasoning, not least theological. This isn’t my area, so forgive me if I pose something that is naïve. However, my understanding of genetic mutation is that it is random. That some feature might be beneficial to my offspring in no way influences what genes my offspring get. A predator-prey explanation assumes that over and over and over again, highly convenient genetic mutations occurred. That is one of my issues with the theory of evolution. Time alone does not guarantee convenient mutations.

    Of course, as a non-scientist (except for training in certain areas of computer science, the history of evolution having a lot of predator-prey interaction, so to speak, is problematic for me theologically. I believe that the human sense of justice reflects the fact that human nature comes from God, who is just. So if I find it disturbing that God either a) designed a method for the development of life forms that requires a massive amount of innocent suffering by prey–which is unjust I think, or b) God started a process that he couldn’t or wouldn’t control that has resulted in massive innocent suffering, it gives me pause to wonder if such a being is even worthy of acknowledgement, let alone worship.

    That is, was the being who “invented” evolution too incompetent to prevent all this tooth and claw business, or too unconcerned about the needless suffering such a process creates to bother to do anything differently? If human nature reflects God’s image somehow (which I would contend cannot be physical, since I doubt seriously that the biblical God needs organs for reproduction or digestion, to name two), then if I care about animals sufferings needlessly at the hands of humans, what does that mean about God? If evolution alone is how all living things came into existence, that suggests to me that many humans are far far superior to any deity who might have started the process. What do you think?

    Ken

    • drandrewwalsh@gmail.com'
      Andy Walsh commented on July 8, 2015 Reply

      Thanks for your thoughts, Ken. A couple of observations:

      Yes, I think sometimes there is a hammer/nail dynamic. There is almost always a way to craft a narrative for why some trait confers a selective advantage, often in a predation context; it is something else entirely to prove that’s what actually happened historically. (Evolutionary psychology, for example, is often criticized as too much of the former and not enough of the latter.) To be clear, the field of evolutionary biology acknowledges a whole range of mechanisms by which diversity arises — a whole toolbox, if you will — but when it comes to communicating with a broader audience it seems like the discussion very quickly narrows to selection only. I think that’s unfortunate, because it creates a lot of misconceptions.

      For example, it creates the impression that predation and the associated suffering of the prey are essential features of evolution, which reasonably raises the question of why God would use a process that requires such suffering. In fact, it is perfectly possible for evolution to occur without that kind of violent, predatory competition. For example, your immune system evolves antibodies to closely match with whatever pathogens you encounter; it needs to be able to do so to keep up with the pathogens themselves evolving. To achieve this, your body doesn’t pit white blood cells (which make antibodies) against each other in violent combat; the matching white blood cells simply divide more, while the non-matching cells live on in case they are needed next time.

      On a larger scale, I heard a talk last week about how Hawaii has a relative dearth of poisonous animals and insects, and plants which have toxic defenses elsewhere in the world lack them in Hawaii. The lushness of the islands means resources are plentiful so competition is less pronounced and brutal tactics aren’t as necessary. To me, this resonates with the way the Bible talks about God want to provide abundantly and describes frameworks for taking care of everyone so as to minimize scarcity of resources that might lead to more pronounced competition.

      As for convenient mutations, there is a sense in which convenient, or advantageous, or useful, mutations are not guaranteed. On the other hand, there is growing evidence that the space of genetic sequences has properties that help the odds but which aren’t immediately intuitive. This is especially true if our intuition comes from thinking about genetic mutations as swapping letters around within words of natural language — ANDREW becomes JNDREW beomces JNKREW and so on until quickly we have gibberish.

      For starters, genetic “spelling” is more forgiving than English spelling. It mhigt be mroe hpleufl to csonider how yuor biran rdeas txet raheter tahn how yuor etiodr deos. Notice how your mind can read that sentence despite most of the words being jumbled; similarly the way the genetic code is read is more forgiving than the way a spell checker approaches text.

      Then, consider that your genetic code, like a document, can be modified in other ways than just the equivalent of letter substitutions. Verbs and nouns can be intensified or subdued by adding adjectives and adverbs, while leaving the basic meaning of the sentence intact. Clauses and phrases can be shifted in order within a sentence; sentences and paragraphs can be moved around. Punctuation changes can be significant, as in the joke about “eats, shoots, and leaves” vs “eats shoots and leaves” as applied to pandas. Equivalents to all of these methods of editing the written word can be found in genetic sequences. Granted, none of these kinds of changes are guaranteed to generate something “better.” But, for me at least, thinking in those terms makes it easier to see how it is possible to make changes that don’t quickly break things, which is the impression one gets just thinking about letter substitutions.

      From there, one has to consider that “better” is a highly dependent notion, rather than an absolute one. What is inconvenient today may be very convenient tomorrow, or vice versa. Since change in the environment is apparently inevitable, there’s a case to be made that it is just, or perhaps merciful, to have a system that creates diversity so that when those changes come, viable solutions are more likely to be available.

      And then one needs to take into account just how many organisms are involved in this searching. The individual chances of finding something convenient may be small, but the global changes are very good, demonstrating the importance of being fruitful and multiplying. This especially true when you get down to the bacterial level, and indeed some of the most critical searching appears to have been done there. The most essential functions of our cells remain, at their core, relatively unchanged from bacteria to us. It appears that the solutions found a long time ago stuck around; they were faithful with a little, and are now asked to be faithful with much. We couldn’t afford to break them in search of something better. Instead, we can only add to them.

      I hope you find that helpful in addressing your questions.

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