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I'm not sure that makes any sense. If there are sudden changes in the environment then the less fit animals will die off without any need for a death gene. If

I'm not sure that makes any sense. If there are sudden changes in the environment then the less fit animals will die off without any need for a death gene. If there aren't any changes in the environment then there's no need for animals to die off. Evolution works just fine with prokaryotes which don't really get old in the sense that we do. Also technology allows us to do many things that aren't allowed for by our evolution, like flying to the Moon. Evolution isn't an all-powerful force but something that works strictly through variation and selection. If we find the physical process that cause aging and how to stop them then there's nothing evolution can do to stop us.

alejohausner 11y ago
Granted, sudden changes to the environment would kill off the less fit individuals. So I'll change my argument a bit: Suppose you've overcome infant mortality, and have also solved the problem of adult mortality, so all subsequent people are immortal. Suppose moreover that young adults insist on having more than zero children (that's likely to continue, you'll agree). Now you've got a population that won't stop growing. Resources are finite, and there will be mass starvation. What are your options in such a scenario? Should you kill off old people, kill off young people, or prevent all future babies? Suppose you prevent all future babies. Then you end up with no more sex, no more genetic variability, and now the whole species might be susceptible to a sudden environmental change. So my argument is that old people must die to make room for genetically-different young people. Without natural death, there will be less room for evolutionary adaptation.
- Symmetry 11y ago
  The question you're asking there is one of human morality and politics rather than evolution or technological feasibility. I'll tell you what solution evolution "wants" to pick: population increase, starvation, and may the fittest win. Obviously that's not something you or I would want but it's why evolution doesn't have any problem with creatures living indefinitely.
  - deleted 11y ago
    [deleted]
  - alejohausner 11y ago
    Well, I wasn't trying to make a moral argument, although I guess the way I phrased things might suggest otherwise. Heck, I just have this strong intuition that there's a countdown timer inside us, which will lead us inexorably to death. Maybe I can't argue convincingly for it, but I feel there have to be evolutionary reasons for why such a timer must exist, and the idea of making room for young organisms seemed like a fruitful way towards an explanation. So here's a last and final argument for such a countdown timer: there are no immortal species in nature. That's more of an "existence proof" than a "constructive proof", but it does strongly argue that there is a reason why death is necessary (without providing the reason, for I can't think of one that will persuade you).
    - ItsDeathball 11y ago
      https://en.wikipedia.org/wiki/Biological_immortality#Organisms https://en.wikipedia.org/wiki/Biological_immortality#Organis... There are actually a few immortal or extremely long-lived species in nature. Evolution still acts upon them because there are other selection forces at work, like not being eaten by predators.
- ewzimm 11y ago
  Depending on what climate change models you believe, we may already have passed the point at which we can prevent mass death due to a sufficiently large population overusing resources. The only realistic ways to deal with this problem is to get more room and resources by developing technology to send people to live on other planets or wrangle asteroids into orbit and build habitable environments on them. We're already well into this process, but the more people we have and the longer they can live, the more able we'll be to build on these technologies. Essentially, the problem is already here, and the solution is more people working on it, which preventing people from losing their ability to function would significantly contribute to.
- ap22213 11y ago
  I like the thought experiment. But, continuing further a little bit, if we had sufficient technology to gain practical immortality, couldn't we also engineer our species to not want to have children AND engineer enough genetic variability?
darkmighty 11y ago
The issue is rate of environment change. If your individuals have 100-year lifetimes and changes occur at 1-year rate, then clearly there's a problem. Even if those 100-year individuals reproduce throughout their lives, the older individuals won't bear modifications. So if the environment can change quickly, it's plausible there's a mechanism to secure existential threats to the species by maintaining a short reproductive cycle at the expense of extra overhead to recreate individuals.
- Symmetry 11y ago
  Generally the metric is how fast the environment changes versus how fast new generations are produced. If a population can breed rapidly then it can adapt to fast environmental changes no matter how long the members live. If it breeds slowly it cannot adapt to rapid environmental changes no matter how long it's members live.
  - darkmighty 11y ago
    I was being careful because I think it's not so simple. Some changes are not deleterious (don't cause death), but still confer subtle cumulative benefits. If individuals live arbitrarily long, you might be accumulating old material that slows down evolution. In that example, if your individuals live for 100 years and you have a 1-year reproduction cycle, each year only 1% of your population is new.
    - Symmetry 11y ago
      That would only be true if all individuals were living to the full 100 years their biology allowed. That the sort of environment that bacteria in a growth medium have but not something you would see in a steady state. And also remember that every organism would reproduce each year so you would have %50 of you population new each year unless the oldest organisms can somehow prevent the youngest ones from reproducing. I would agree that that last would be something that evolution would tend to prevent.
      - 11y ago
deleted 11y ago
[deleted]
- alejohausner 11y ago
  Speaking of Freud, here's a joke: Someone once asked Freud, "what stands between fear and sex?" Freud replied, "ah... yes, that's a very interesting question: between vier and sechs stands funf!"

alejohausner 11y ago

Granted, sudden changes to the environment would kill off the less fit individuals. So I'll change my argument a bit: Suppose you've overcome infant mortality, and have also solved the problem of adult mortality, so all subsequent people are immortal. Suppose moreover that young adults insist on having more than zero children (that's likely to continue, you'll agree). Now you've got a population that won't stop growing. Resources are finite, and there will be mass starvation. What are your options in such a scenario? Should you kill off old people, kill off young people, or prevent all future babies? Suppose you prevent all future babies. Then you end up with no more sex, no more genetic variability, and now the whole species might be susceptible to a sudden environmental change. So my argument is that old people must die to make room for genetically-different young people. Without natural death, there will be less room for evolutionary adaptation.

Symmetry 11y ago
The question you're asking there is one of human morality and politics rather than evolution or technological feasibility. I'll tell you what solution evolution "wants" to pick: population increase, starvation, and may the fittest win. Obviously that's not something you or I would want but it's why evolution doesn't have any problem with creatures living indefinitely.
- deleted 11y ago
  [deleted]
- alejohausner 11y ago
  Well, I wasn't trying to make a moral argument, although I guess the way I phrased things might suggest otherwise. Heck, I just have this strong intuition that there's a countdown timer inside us, which will lead us inexorably to death. Maybe I can't argue convincingly for it, but I feel there have to be evolutionary reasons for why such a timer must exist, and the idea of making room for young organisms seemed like a fruitful way towards an explanation. So here's a last and final argument for such a countdown timer: there are no immortal species in nature. That's more of an "existence proof" than a "constructive proof", but it does strongly argue that there is a reason why death is necessary (without providing the reason, for I can't think of one that will persuade you).
  - ItsDeathball 11y ago
    https://en.wikipedia.org/wiki/Biological_immortality#Organisms https://en.wikipedia.org/wiki/Biological_immortality#Organis... There are actually a few immortal or extremely long-lived species in nature. Evolution still acts upon them because there are other selection forces at work, like not being eaten by predators.
ewzimm 11y ago
Depending on what climate change models you believe, we may already have passed the point at which we can prevent mass death due to a sufficiently large population overusing resources. The only realistic ways to deal with this problem is to get more room and resources by developing technology to send people to live on other planets or wrangle asteroids into orbit and build habitable environments on them. We're already well into this process, but the more people we have and the longer they can live, the more able we'll be to build on these technologies. Essentially, the problem is already here, and the solution is more people working on it, which preventing people from losing their ability to function would significantly contribute to.
ap22213 11y ago
I like the thought experiment. But, continuing further a little bit, if we had sufficient technology to gain practical immortality, couldn't we also engineer our species to not want to have children AND engineer enough genetic variability?

darkmighty 11y ago

The issue is rate of environment change. If your individuals have 100-year lifetimes and changes occur at 1-year rate, then clearly there's a problem. Even if those 100-year individuals reproduce throughout their lives, the older individuals won't bear modifications. So if the environment can change quickly, it's plausible there's a mechanism to secure existential threats to the species by maintaining a short reproductive cycle at the expense of extra overhead to recreate individuals.

Symmetry 11y ago
Generally the metric is how fast the environment changes versus how fast new generations are produced. If a population can breed rapidly then it can adapt to fast environmental changes no matter how long the members live. If it breeds slowly it cannot adapt to rapid environmental changes no matter how long it's members live.
- darkmighty 11y ago
  I was being careful because I think it's not so simple. Some changes are not deleterious (don't cause death), but still confer subtle cumulative benefits. If individuals live arbitrarily long, you might be accumulating old material that slows down evolution. In that example, if your individuals live for 100 years and you have a 1-year reproduction cycle, each year only 1% of your population is new.
  - Symmetry 11y ago
    That would only be true if all individuals were living to the full 100 years their biology allowed. That the sort of environment that bacteria in a growth medium have but not something you would see in a steady state. And also remember that every organism would reproduce each year so you would have %50 of you population new each year unless the oldest organisms can somehow prevent the youngest ones from reproducing. I would agree that that last would be something that evolution would tend to prevent.
    - 11y ago

deleted 11y ago

[deleted]

alejohausner 11y ago
Speaking of Freud, here's a joke: Someone once asked Freud, "what stands between fear and sex?" Freud replied, "ah... yes, that's a very interesting question: between vier and sechs stands funf!"