I’ve never really thought about this until recently, but evolution stops at procreation, I believe. So the only developments that my daughter might inherit from my own evolution have already been defined. (There’s a joke quite close to the surface there about regression as opposed to evolution, but I’ll leave that to the lesser people.)

I thought about this while cutting the skin off a couple of salmon fillets while preparing dinner yesterday evening. I thought how convenient it was that salmon skin is so resistant to my über-sharp knife, allowing me to slice the meat cleanly off the skin in one fell swoop.

Maybe people would be less likely to eat (and therefore kill) salmon if the salmon was less easy to skin. But salmon will never evolve to have more cuttable skin specifically to give chefs a headache, because the culinary experience not only happens after procreation, it happens after death.

And a side question: do events we see other people experience feed into our evolutionary pass-down? Or is it purely based on our own experience? If the latter, then surely humans will evolve at the detriment of people older than procreation age. It’s just a thought.


9 Responses to “Evolution”

  1. Bloom Blog on December 4th, 2007 06:36

    Evidence suggests that evolution doesn’t stop at procreation. It’s apparent that we’re born with a high degree of plasticity – our brains are wired partly by our own experience. This astonishing revelation has profound implications, not the least of which is that your work with your daughter is not done. You are moulding her – literally and figuratively – every time she sees you.

    No pressure though.

  2. Dan on December 4th, 2007 06:51

    In this particular instance, I’m thinking of evolution as purely the biological pass-down from parents, as opposed to the way in which we evolve through our experiences during life.

    If I, for example, decide to go for a run every lunchtime (unbeknownst to my daughter), then any evolution that ensues (increased lung capacity, for example) will not be passed on to her. Yet if I’d done it before her conception, then there’s a chance that she might have benefited…

  3. Bloom Blog on December 4th, 2007 18:06

    Yes but you’re running into trouble here because you are differentiating between biological and experiential evolution and this difference is not as straightforward as you make out. The way you interact with your daughter affects the biological make up of the brain. Therefore there is no way you can say that the biological pass-down has finished at conception.

    Even your example of going for a run every lunchtime is not straightforward, as your example is likely to influence your daughter over her lifetime. Given the evidence for the brain’s plasticity, it’s hard to argue that this sort of example is not part of your biological pass-down.

    And I didn’t understand your final point in the blog, but all very interesting.

  4. Tom on December 4th, 2007 19:16

    Sounds like you are thinking of the out of fashion idea of Inheritance of Acquired Characteristics called Lamarckism.

    You supply your daughter with a random half of your genome. Going for a run doesn’t make your genes any fitter.

    So Evolution is not something which occurs over a lifetime, it is simply the number of procreating descendants you end up having.

    You are also mistaken about the salmon. New characteristics first appear by random variation in the genome. So being less tasty or filletable could arise by chance, chefs would start asking for that type of fish less and they would prosper and become more numerous than their fellow tastier more easily prepared brethren.

    You really need to read a book or two by Richard Dawkins. I suggest The Selfish Gene for starters. You’ll enjoy it.

  5. Dan on December 5th, 2007 00:12

    Thanks, Thomas.

    Bloom, or can I call you Robert. Re. my last paragraph. If I see an old man struggling to open a Twix, do I evolve to better cope with Twix-opening, or indeed do I pass down some attribute allowing my daughter to more easily open Twixes in her old age? The opening of Twix bars serves merely as an example, and could be extrapolated to other bars of chocolate, nay other walks of life.

  6. Steve on December 5th, 2007 01:18

    Bugger, I meant to respond to this earlier and am a couple of comments behind by now…

    Not sure about your definition of evolution, as the collection of genes that form the organism that is you can’t alter throughout your life, no matter how much exercise you do. The best you can hope for is to pass them on to offspring.

    In order for you to benefit from increased lung capacity as a result of exercise, you would already have to possess the gene which predisposes you to this outcome. If the gene was new and existed only as an element of mutation, ie. had not existed in either your mum or dad (obviously this is not the case as cardio-vascular activity = increased lung capacity for all humans), there is a 50/50 chance your lovely daughter would inherit it through you.

    Ergo, if your daughter decides at some point to engage in similar foolish activities such as pounding the streets of Londontown, there’s a hypothetical half-chance she’ll already be fully equipped if she’s inherited the genes which will result in an increase in lung capacity, whether you have engaged in similar activity in any part of your life or not.

    If you’d never pulled on a pair of Nike’s in your life and chose to live your life glued to the sofa with a tartan blanket on your knees, subsisting on a diet of fish suppers and Werther’s Originals, your offspring (if you discount more temporal influences such as diet, culture and upbringing) is just as likely to be an Olympian as if you were a complete Sport Billy.

    In a nutshell, if a mutation develops which is found to be beneficial to the perpetuation of life for itself (irrespective of the larger organism in which it operates), then it will prevail and continue down the generations. There is no way a man can influence the genes of potential offspring while he is alive as he is already the inheritor of generations of genetic muddling (women, while unable to alter genes, are obviously able to affect the health of offspring in other ways by not smoking fags etc. but these are superficial effects and in no way influence the “construction” of the individual).

    So relax and put your feet up…

  7. Thomas on December 5th, 2007 19:25

    Thanks for explaining the twix point Dan, I see what you’re getting at now.

    It’s like saying if we lived on the N.E. coast of England & were pure descendants of Anglo-Saxons living in that region for centuries, is it possible that we would find the sight of a helmet with upturned horns *inherently* frightening. A kind of Genetic Memory.

    The problem with this idea is that DNA–>body is a one-way process. As Dawkins puts it, DNA is *not* like a blueprint for a human body (or mind). It is much more like a recipe, such that there is *not* a simple correspondence between a part of the body (or mind) and a region in DNA. This is why something that you do or experience in you life *cannot* affect your DNA in a meaningful way.

    Again, see The Selfish Gene for a very lucid explanation of this whole area.

  8. Bloom Blog on December 6th, 2007 08:45

    Hmm, a fascinating debate and Dan you may remember that I recommended The Selfish Gene to you some 12 months ago. It is a genuinely life changing book, full of numbers and probability, which you are sure to enjoy. However, as an aside I never understood how a random mutation leads to the acquisition of entirely new, revolutionary phenomena. Like wings for example – were they a mutation? Perhaps someone can explain that to me?

    My point is a narrower one which by extension leads me to disagree with Steve and, I think, Tom, even though everything they have said is 100% accurate. I disagree for two reasons:
    1. If you were to deprive your daughter of love – if you ignored her cries and refused to acknowledge her, she would be deeply unhappy. But the difference would not simply be experiential. It would also be biological. Being deprived of love at an early age affects the development of the prefrontal cortex – that is the make up of the brain itself is altered(hence the importance of plasticity). So it is not so much nature vs nurture, but nature, followed by nurture influencing nature.
    Of course, depriving your daughter of love is somewhat more drastic than going for a run. But if we accept the point about the brain’s plasticity, then although the direct evolutionary benefits of you going for a run will have no impact, your overall shaping of your daughter’s world, over time, will.
    2. My secondary argument is about what evolution actually is. It is not impossible to imagine that the example you set for your daughter – not to mention the heightened energy, lessened depression, increased happiness, will almost certainly help form an attitude in her about the positive benefits of exercise. And how is an attitude any less a pass down (though admittedly not biological)? Indeed, this is akin to Dawkins’ idea of memes, and overlaps your point about twix bars. No, we won’t evolve biologically to open Twix bars more easily, but we will evolve through ideas to the stage where Twix bars are easier to open.

    But this is a secondary argument. My primary argument is that everything you consistently do influences your daughter, and in some instances this influence is biological as well as psychological.

  9. Tom on December 6th, 2007 17:57

    Dan said:
    In this particular instance, I’m thinking of evolution as purely the biological pass-down from parents, as opposed to the way in which we evolve* through our experiences during life.

    Bloom that’s the only reason I may have sounded a bit DNA-nature is everything. I actually totally agree with both your points. Humans make for just about the most helpless infants in the whole animal kingdom. Moreover we have the longest period of mental and physical growth during which we need and benefit from almost constant parental care.

    If you see video of places like the heart breaking Albanian orphanages (and the present day equivalents which still exist to this day within this continent) you’ll see skinny but fed kids. They are literally tragically starving for love.

    I apologise for making you think about that. hmmm.

    Re wings: spontaneous mutation i.e. the whole wing appearing in one generation would be like tossing a 5000 picture jigsaw in the air and it landing fully complete. The ONLY way it can form is gradually, what’s more each intermediate must benefit the organism. But the body part is allowed to start off being used for a completely difference purpose. So maybe big lizards benefited from superior cooling by having flaps between their arms and sides. Then maybe that enable
    them to glide like several animals do today. Each time they randomly got bigger or stronger or lighter they could more successfully live their life and escape prey are make more babies than their rivals. You have to take in to account the long time spans.

    *By the way we don’t evolve during our lives, not in the technical sense. We develop.

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