4 ms·

It's true that individuals that live a little bit longer but have the same end of their reproductive period do no better in the gene pool. However, if it were

by araneae 17y ago

It's true that individuals that live a little bit longer but have the same end of their reproductive period do no better in the gene pool. However, if it were advantageous to live longer, and those folks had a slightly longer reproductive period, then we would expect the lifespan-while-fertile to increase. Presumably this would also increase the overall lifespan as well, but really that's irrelevant to this discussion. Yes, we keep accumulating damage. But we have mechanisms to control that damage. And clearly there's not a set limit on it. Tarantulas that only live 2 years are not constrained by cell damage. Cell damage is allowed to happen.

dfranke 17y ago
Through your own argument, you've conceded that aging happens when the body doesn't invest enough resources in controlling damge, and that the amount of investment made can vary widely between species and even within a species. So then what in the world leads you to believe that, provided with appropriate medical support, the body can't be made to invest far more?
- araneae 17y ago
  I conceded nothing. You're confusing investment on an evolutionary timescale with investment on an individual timescale. A male spider couldn't spontaneously decide to live another 6 years- it would take hundreds of thousands of years of evolution to achieve that. On a physiological level, increasing investment in the individual is difficult because so much about how we are built is developmentally fixed. You can't cure a kid with Down's Syndrome by taking out every extra third chromosome in every cell. However, we know what genotype would produce a non Down's baby. In the near future, we might be able to clone a trisomy 21 person and produce a non Down's syndrome clone. But we can't produce a clone of that person that won't age. We have no idea which genes contribute to aging, and how, and even how many. In all likelihood a simply astronomical number of genes would have to be altered to extend life.
  - MikeCapone 17y ago
    Here's you've just shown that you have no idea what Aubrey and SENS are proposing. Maybe, like with Hofstadter's book, you've just "read the introduction" and then stopped? >We have no idea which genes contribute to aging, and how, and even how many. In all likelihood a simply astronomical number of genes would have to be altered to extend life. The whole point of SENS is that it DOESN'T try to fiddle with metabolism (our genes). All of the genetic diseases you mention are different from the diseases of aging, so they're a bad example. SENS is all about maintenance and periodical repair (like with an antique car, for example). Every, say, 10 years you go in and they remove accumulated damage (which can only be present in a limited number of long-lived molecules) BEFORE it causes pathologies. Most of this can probably be done with your own immune system (you train it to recognize some molecules), and some of it will have to be done other ways (gene therapy to make your body produce certain enzymes, etc).
    - araneae 17y ago
      I know exactly what he's proposing. What I am saying is that it won't work, because aging has to do with developmentally fixed processes. Sure, you can replace blood cells, but do you really think we can replace all your cells, including your neurons? If you want to go in for a complete brain transplant, be my guest.
    - MikeCapone 17y ago
      > I know exactly what he's proposing. What I am saying is that it won't work, because aging has to do with developmentally fixed processes. No you don't know "exactly" what he's proposing, and you don't understand what senescence is, as you've made clear many times here. I'm starting to feel this isn't very productive so we should probably stop this conversation. > Sure, you can replace blood cells, but do you really think we can replace all your cells, including your neurons? If you want to go in for a complete brain transplant, be my guest. Here you show again that you have no idea what SENS is proposing and you are making up strawmen. If you want to criticize something, please learn about it first.
MikeCapone 17y ago
1) For most of history, humans and their ancestors didn't live very long. When you die at 30, there's not much selection for biological mechanisms to fix the problems that happen in someone who is 60. Natural selection is looking for genes that are good at reproducing themselves, not genes that are good at giving an individual long life. Once you have sexual reproduction in place, it is much simpler to just have lots of offspring than to evolve even more repair mechanisms to extend life (at no great benefit to genes). 2) That's the whole point of SENS; repairing the damage for which we DON'T have repair mechanisms because of point #1. For example, our lysosomes (the "garbage collector/incinerator" in our cells) accumulate some molecules that they can't break down because they don't have the right enzymes, so they accumulate throughout our lives and end up affection cell function all around our bodies (lysosomes are full and can't do their jobs anymore). SENS has found other organisms that do have these enzymes, and are looking at ways for us humans to use those enzymes to clean up that "long-lived garbage". > Cell damage is allowed to happen. Yes, because your genes don't care about you (so to speak - read Dawkins's The Selfish Gene). After you've reproduced, there's no pressure to fix damage that only affects you after reproduction age. Nothing causes more suffering in the world than the diseases of aging, and curing those diseases should be priority #1. Living longer is just a welcome side-effect.
- araneae 17y ago
  >For most of history, humans and their ancestors didn't live very long. Again, this is completely irrelevant to your argument. You can still evolve to live for a longer time while reproductively viable. >Once you have sexual reproduction in place, it is much simpler to just have lots of offspring than to evolve even more repair mechanisms to extend life (at no great benefit to genes). Again, it's all about trade-offs. For some organisms, it's most advantageous for them to reproduce as much as they can all in one go, and for others it makes sense to live a really long time and reproduce throughout that time period. See http://en.wikipedia.org/wiki/Semelparity_and_iteroparity http://en.wikipedia.org/wiki/Semelparity_and_iteroparity I own The Selfish Gene. And unlike you, I've read most of his actual scientific work as well, not just his work for the plebeian.
  - 17y ago

by araneae 17y ago

dfranke 17y ago

Through your own argument, you've conceded that aging happens when the body doesn't invest enough resources in controlling damge, and that the amount of investment made can vary widely between species and even within a species. So then what in the world leads you to believe that, provided with appropriate medical support, the body can't be made to invest far more?

araneae 17y ago
I conceded nothing. You're confusing investment on an evolutionary timescale with investment on an individual timescale. A male spider couldn't spontaneously decide to live another 6 years- it would take hundreds of thousands of years of evolution to achieve that. On a physiological level, increasing investment in the individual is difficult because so much about how we are built is developmentally fixed. You can't cure a kid with Down's Syndrome by taking out every extra third chromosome in every cell. However, we know what genotype would produce a non Down's baby. In the near future, we might be able to clone a trisomy 21 person and produce a non Down's syndrome clone. But we can't produce a clone of that person that won't age. We have no idea which genes contribute to aging, and how, and even how many. In all likelihood a simply astronomical number of genes would have to be altered to extend life.
- MikeCapone 17y ago
  Here's you've just shown that you have no idea what Aubrey and SENS are proposing. Maybe, like with Hofstadter's book, you've just "read the introduction" and then stopped? >We have no idea which genes contribute to aging, and how, and even how many. In all likelihood a simply astronomical number of genes would have to be altered to extend life. The whole point of SENS is that it DOESN'T try to fiddle with metabolism (our genes). All of the genetic diseases you mention are different from the diseases of aging, so they're a bad example. SENS is all about maintenance and periodical repair (like with an antique car, for example). Every, say, 10 years you go in and they remove accumulated damage (which can only be present in a limited number of long-lived molecules) BEFORE it causes pathologies. Most of this can probably be done with your own immune system (you train it to recognize some molecules), and some of it will have to be done other ways (gene therapy to make your body produce certain enzymes, etc).
  - araneae 17y ago
    I know exactly what he's proposing. What I am saying is that it won't work, because aging has to do with developmentally fixed processes. Sure, you can replace blood cells, but do you really think we can replace all your cells, including your neurons? If you want to go in for a complete brain transplant, be my guest.
  - MikeCapone 17y ago
    > I know exactly what he's proposing. What I am saying is that it won't work, because aging has to do with developmentally fixed processes. No you don't know "exactly" what he's proposing, and you don't understand what senescence is, as you've made clear many times here. I'm starting to feel this isn't very productive so we should probably stop this conversation. > Sure, you can replace blood cells, but do you really think we can replace all your cells, including your neurons? If you want to go in for a complete brain transplant, be my guest. Here you show again that you have no idea what SENS is proposing and you are making up strawmen. If you want to criticize something, please learn about it first.

MikeCapone 17y ago

1) For most of history, humans and their ancestors didn't live very long. When you die at 30, there's not much selection for biological mechanisms to fix the problems that happen in someone who is 60. Natural selection is looking for genes that are good at reproducing themselves, not genes that are good at giving an individual long life. Once you have sexual reproduction in place, it is much simpler to just have lots of offspring than to evolve even more repair mechanisms to extend life (at no great benefit to genes). 2) That's the whole point of SENS; repairing the damage for which we DON'T have repair mechanisms because of point #1. For example, our lysosomes (the "garbage collector/incinerator" in our cells) accumulate some molecules that they can't break down because they don't have the right enzymes, so they accumulate throughout our lives and end up affection cell function all around our bodies (lysosomes are full and can't do their jobs anymore). SENS has found other organisms that do have these enzymes, and are looking at ways for us humans to use those enzymes to clean up that "long-lived garbage". > Cell damage is allowed to happen. Yes, because your genes don't care about you (so to speak - read Dawkins's The Selfish Gene). After you've reproduced, there's no pressure to fix damage that only affects you after reproduction age. Nothing causes more suffering in the world than the diseases of aging, and curing those diseases should be priority #1. Living longer is just a welcome side-effect.

araneae 17y ago
>For most of history, humans and their ancestors didn't live very long. Again, this is completely irrelevant to your argument. You can still evolve to live for a longer time while reproductively viable. >Once you have sexual reproduction in place, it is much simpler to just have lots of offspring than to evolve even more repair mechanisms to extend life (at no great benefit to genes). Again, it's all about trade-offs. For some organisms, it's most advantageous for them to reproduce as much as they can all in one go, and for others it makes sense to live a really long time and reproduce throughout that time period. See http://en.wikipedia.org/wiki/Semelparity_and_iteroparity http://en.wikipedia.org/wiki/Semelparity_and_iteroparity I own The Selfish Gene. And unlike you, I've read most of his actual scientific work as well, not just his work for the plebeian.
- 17y ago