Was Lamarck right along? Why evolution doesn’t work like we thought it did

I expect most Futurismic regulars, much like myself, think they understand the basics of Darwin’s theory of evolution: random mutations occur in each generation, natural selection culls the poor adaptations, repeat and rinse ad infinitum, and the life a creature lives doesn’t affects its genetic legacy.

Well, here’s the thing: it turns out that the last point there – one which I’ll freely admit to having pedantically called people out on for years – may well not be true at all [via Kate Feld]:

… we’ve come to understand that the awesome power of natural selection – frequently referred to as the best idea in the history of science – lies in the sheer elegance of the way such simple principles have generated the unbelievable complexities of life. From two elementary notions – random mutation, and the filtering power of the environment – have emerged, over millennia, such marvels as eyes, the wings of birds and the human brain.Yet epigenetics suggests this isn’t the whole story. If what happens to you during your lifetime – living in a stress-inducing henhouse, say, or overeating in northern Sweden – can affect how your genes express themselves in future generations, the absolutely simple version of natural selection begins to look questionable. Rather than genes simply “offering up” a random smorgasbord of traits in each new generation, which then either prove suited or unsuited to the environment, it seems that the environment plays a role in creating those traits in future generations, if only in a short-term and reversible way.


Epigenetics is the most vivid reason why the popular understanding of evolution might need revising, but it’s not the only one. We’ve learned that huge proportions of the human genome consist of viruses, or virus-like materials, raising the notion that they got there through infection – meaning that natural selection acts not just on random mutations, but on new stuff that’s introduced from elsewhere. Relatedly, there is growing evidence, at the level of microbes, of genes being transferred not just vertically, from ancestors to parents to offspring, but also horizontally, between organisms.


Among the arsenal of studies at Shenk’s disposal is one published last year in the Journal of Neuroscience, involving mice bred to possess genetically inherited memory problems. As small recompense for having been bred to be scatterbrained, they were kept in an environment full of stimulating mouse fun: plenty of toys, exercise and attention. Key aspects of their memory skills were shown to improve, and crucially so did those of their offspring, even though the offspring had never experienced the stimulating environment, even as foetuses.

“If a geneticist had suggested as recently as the 1990s that a 12-year-old kid could improve the intellectual nimbleness of his or her future children by studying harder now,” writes Shenk, “that scientist would have been laughed right out of the hall.” Not so now.

And cue selective quote-mining by adherents of Creationism and other theologically-compromised pseudosciences in three, two, one…

6 thoughts on “Was Lamarck right along? Why evolution doesn’t work like we thought it did”

  1. Okay, if I’m to ultra-simplify this down to one sentence it would read: Evolutionarily relevant mutations can occur DURING a person’s life, and can occur due to lifestyle and environment.

    Is that a reasonable way of interpreting this? I’m just trying to wrap my head around it.

  2. You’re close, I think; mutations only happen between generations, but environmental effects can modify the level to which subsequent mutation express. That said, I’d like the input of someone with a firmer grounding in evolution and biology to be sure…

  3. I wonder if you could get Peter Watts to write for you. These days he’s my favourite source for riding that thin edge between hard science and future speculation.

  4. “Evolutionarily relevant mutations can occur DURING a person’s life, and can occur due to lifestyle and environment. Is that a reasonable way of interpreting this?”

    Not really, at least according to the original sense by which most people understood “mutation”. If you imagine one’s genetic makeup as, say, a billboard made up of lightbulbs, a “mutation” in the old understanding was thought to be a complete change in the position, colour or existence of some of the bulbs, such that a 2nd-generation sign was a physically different construct from its predecessor; and the only time such bulbs could move, change or be removed was during the “building” of the next generation of signs, which was why it took so many generations for the “picture” on the sign to completely change.

    In the epigenetics understanding, a “mutation” is simply a change as to which lights actually get turned on or off, but the “off” lights are still there (as opposed to the original idea which had them being completely destroyed or removed) and could theoretically re-express in another generation given proper environmental cues. The next generation may show a different picture than its predecessor, but the potential to change is much greater and quicker than anticipated.

    In some ways epigenetics actually bolsters the case for random variation, because it hugely increases the frequency with which variations can occur in a set time and simultaneously includes a mechanism by which such variations can occur without killing the majority of their carriers (as most actual mutations which produce actual genetic differences do; it’s called cancer). In other ways, it completely undermines evolutionary psychology, because if genetic expression can be contingent on behaviour then that suggests the evolution follows the psychology, and not the other way around. (Which resonates neatly with some fascinating developments in neuroplasticity: read “The Brain that Changes Itself”, by Norman Doidge, for some startling revelations on this.)

  5. I have asked him a few times, actually, but he’s a busy man (especially at the moment, courtesy US Border Patrol), and I can’t afford to pay him even a tenth of what his work would be worth, sadly. But if you’re reading, Peter, the door’s always open…

  6. Hmm. But wouldnt it be fair to say that theologically minded people would predict that the actions of the parents affect generations after them–and that could even be genetically transmitted? This of course has huge implications–our behavior affects future generations.

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