Why do we grow older?

Discussion in 'Biology & Genetics' started by Gale, Dec 4, 2010.

  1. Gale Registered Member

    Is there any benefit to animals aging? Why do we physically age; why do we die of old age; what is the point of aging (in evolutionary terms)?
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  3. cosmictraveler Be kind to yourself always. Valued Senior Member

    I always enjoy a good slice of aged meat, it is much better tasting and a glass of aged wine to go along with it makes it even more enjoyable.

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  5. James R Just this guy, you know? Staff Member


    Another question would be: is there any benefit to animals staying alive beyond reproductive age? And the answer to that, from the point of view of the genes, is mostly "no", I think.
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  7. Kennyc Registered Senior Member

    For evolution, for the species, for ever.

    Life is bigger....bigger than you and you are not me.
    - Michael Stipe
  8. francois Schwat? Registered Senior Member

    In our day, I find it increasingly common to see grandparents taking care of grandchildren.

    There are a number of old people who are still relatively strong and are glad to take on caring for their kin. That may be why we're able to be as old as 125.
  9. francois Schwat? Registered Senior Member

    As for why we get older, it is helpful. It makes sure our genes continue to shuffle.

    Though it's helpful, I doubt that's why we age. I think it has something to do with an inherent limitation in how we evolved. Our genes exhibit their traits not just against the backdrop of our physical environment, but against the backdrop of their respective neighbor genes. Our genes have pleiotropic effects (meaning, they don't just have a singular phenotypic effect, but potentially many). When you consider that we have a bunch of genes (around 40,000?) which all have complicated interweaving effects on one another, and you consider that it's lucky if a single given gene has a positive effect, then you're pretty damn fortunate that you're healthy at any given time.

    As we know, genes' effects on us change as we age. Of course they're going to be good effects when we're young because they need to be; otherwise, we wouldn't be capable of reproducing. But as you get older, man, it's simple statistics. There's no great reason for those genes to continue to have great function in your old age, and so those changes which must occur, as they are part of our genetic mechanism, are going to be harmful. As you get older and older, you accumulate more and more damage until one of your organ systems collapse and you die.
  10. kmguru Staff Member

    The situation may change though based on evolution. You see as life becomes highly complex, beyond hunting, gathering, eating and making babies - the society requires Knowledge Management to reach the stars - the ultimate spreading of human seeds.

    Under those scenarios, humans have to live longer to manage the development cycle of the specie. So, either nature will turn on/off a few genes or we will do it for ourselves.

    Already research is going on to safely activate Telomeres...who know, what else is out there...
  11. WillNever Valued Senior Member

    We grow older because of time.

    You need to redefine what you are talking about. Are you talking about why humans develop osteoarthritis in old age? Why they develop heart failure? Why renal function declines? Which part of "growing older" are we talking about?

    There are completely explainable and nonmysterious reasons for why these diseases occur that have nothing to do with "telomeres" or the other crap people have so-far mentioned in this thread.
  12. Gale Registered Member

    I am not speaking of any specific health problem associated with age, I speak of all the usual symptoms of aging: Becoming wrinkly, having hair go grey and fall out, becoming gradually more vulnerable to disease, sagging breasts, declining ability to remember and learn, an increasingly raspy voice, the need to sleep more, loss of hearing. Even before reaching menopause, women experience disadvantage from aging as your chance of giving birth to a deformed baby increases as you grow older.

    Past puberty, increasing in age brings nothing but disadvantages to your health, and disadvantages to your community as they have to help to sustain you.

    "Time" seems like a fairly weak reason for aging, as some animals age much faster than others, and some forms of life do not age at all.
    So why don't some plants die of old age if they only need to be alive for a few years to pass their genes onto the next generation? Some trees have been alive for thousands of years.
  13. Fraggle Rocker Staff Member

    Every year they produce more seeds, spores, whatever. This increases the chance of their own genes surviving longer.

    This is rather common. All vertebrates and many of the lower orders of animals also go through more than one reproductive cycle.

    Many plants die of "old age" after just one reproductive cycle.

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