Tag Archives: Darwin

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

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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…

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Why you have (or had) an appendix

CT scanThe image of the appendix has been getting a makeover. Two years ago, Duke U. researchers suggested it is not the useless evolutionary vestige that Darwin said it was.

The appendix, they said, is a safe haven where good bacteria could hang out until they were needed to repopulate the gut after a nasty case of diarrhea, for example.

Now some of the team suggest the appendix has been around a lot longer than Darwin thought.

[Surgical sciences professor William] Parker and colleagues found that the appendix has evolved at least twice, once among Australian marsupials and another time among rats, lemmings and other rodents, selected primates and humans. “We also figure that the appendix has been around for at least 80 million years, much longer than we would estimate if Darwin’s ideas about the appendix were correct.”

Parker says Darwin just didn’t have access to enough information about the organ.

“If he had known about the widespread nature of the appendix, he probably would not have thought of the appendix as a vestige of evolution.”

He also was not aware that appendicitis, or inflammation of the appendix, is not due to a faulty appendix, but rather due to cultural changes associated with industrialized society and improved sanitation. “Those changes left our immune systems with too little work and too much time their hands – a recipe for trouble,” says Parker.

[Story tip: Phoenix New Times blog; CT image by jellywatson]

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Darwin as a religious icon

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Charles Darwin portraitIt is, of course, the 200th anniversary of Charles Darwin’s birth, which is a cause for celebration if you’re of a scientific mind. But how much celebration is really appropriate? [image courtesy Wikimedia Commons]

Responding at the Guardian to artist Damien Hirst’s gushing foreword to a new edition of The Origin of Species (as well as to Darwin’s unfortunate position in the middle of the tug-o’war between fundamentalist religion and militant atheism) Andrew Brown wonders whether the pedestal on which we’ve put Darwin is too high – and whether some of his more fervent supporters, in using him as an icon against religion, have in fact made a religion of him:

… treating Darwin, or any other scientist, as a wonder-worker just turns science into a priesthood. That doesn’t do anyone any good, neither scientists nor the rest of us. Darwin was a good man and his theory was a great one. But believing it, even understanding it, won’t make the goodness and the greatness rub off on the believers.

To be honest, the whole battle between the crusading atheists and their target pockets of the irrational is starting to worry me in just the same way as the fundamentalist sects. I’m an atheist myself, but I work on the principle that if I object to having someone else’s ideology crammed down my throat, they probably won’t like me doing it to them either.

And, as a matter of pragmatism, persecuting the irrationally religious does little beyond creating martyrdom, and the last thing we need is more people fixated on that.