Why isn't biological immortality a trait?

[WestAir]

Pretty straightforward. So genetic traits mutate over time and the organism with the best traits survives. Since survival of the fittest is the name of the game, then the most long-living organism should have a fairly obvious advantage. Why hasn't organism immortality become a popular trait among complex organisms? I imagine the whole cause of the hayflick limit can naturally be prevented if the proper genetic mutation were to occur. (How hard can it be to replace telomers?)

We've had billions of years to overcome senescence and reap the benefits of biological immortality - so why hasn't this happened? It seems pretty straightforward that a species that doesn't have to contend with age-death would have a better chance of survival.

[NFUN]

It isn't advantageous, or at least wouldn't be in the near term needed for the trait to be selected for without a host of other adaptations. There is a limited amount of space and resources, and older individuals crowding out the young wouldn't be very useful. Aging also wouldn't likely be completely absent, and the elder individuals might remain virile but have lower-quality gametes. 

As to "how hard can it be to replace telomeres", directed evolution isn't really a thing. Wings could be useful to humans for example, but in order for them to work we'd need a faster metabolism, other sensory organs, stronger muscles, etc. These other traits might not be selected for, and thus flight is unlikely to evolve in an organism similar to us modern humans.

Edited February 1, 2016 by NFUN

[Gaarst]

Living billions of years is pointless if you can't survive 1 day before being eaten by a predator or starving.

Besides the biological processes of aging that make it extremely hard to achieve immortality, it is not that useful as short term surviving is more important than long term for most species.
The only species for which surviving isn't that much of a concern anymore is man; but you're not getting immortal in 10,000 years, evolution takes a lot more time, especially for processes involving major changes in cellular/DNA mechanics.

And also, the major factor that makes a genetic trait appear and spread is reproduction. Sure an immortal being is able to have a lot more descendants than a mortal one. But 10 generations of mortal being will have as much descendants as one in 10 generations. Even if immortality appears as a trait, its chances to spread to the whole species are very small.

Also, for a population made of immortal beings, you are quickly going to run into surpopulation and consanguinity issues.
Immortal or not, you are going to starve if your species eats all food in the region; and while animals don't care about ethics of incest, it is still a bad thing genetically, allowing genetic diseases to spread much more.

Edited February 2, 2016 by Gaarst

[AngelLestat]

no, there is no perfection because we live in an environment that is always changing..  if you can not deal with the changes fast enough you get extinct.

If you live a lot of years, it means that you evolve very slow, for example a mosquito or a bacterium can evolve in weeks or months.
Also the evolution does not happen around the individual or species. It happens around the gene.  So the only subject who wants to survive is the gene here.

You can also ask why our body does not have any defence against cancer..  Because we reproduce at younger age than average cancer age.
If you try to push the reproduction age higher each generation, evolution will deal with the cancer problem allowing you to live longer.

By the way.. there is an species of jellyfish that if it needs, it can be inmortal.

Edited February 2, 2016 by AngelLestat

[Kerbart]

I read recently that researchers had managed to produce self-reproducing chemicals. One of the things they learned form their experiment, they said, was that death was essential for the evolution mechanism. Change was only possible if the previous generation went out of the way.

So with that in mind, perhaps it's built-in; species who die might, evolutionary, do better than the species who get stuck with "the old ones."

[WestAir]

10 minutes ago, Kerbart said:

I read recently that researchers had managed to produce self-reproducing chemicals. One of the things they learned form their experiment, they said, was that death was essential for the evolution mechanism. Change was only possible if the previous generation went out of the way.

So with that in mind, perhaps it's built-in; species who die might, evolutionary, do better than the species who get stuck with "the old ones."

That's actually a really interesting line of thought. I hadn't considered that immortality could be a detriment to survival of the fittest.

[Bill Phil]

If the goal of life is to pass on genetic material, then immortality isn't necessarily a good thing to have. As long as our genes are passed, then does it matter if we die?

[YNM]

We're not immortal because we reproduce sexually. Evolution can only happens in those cases, where you share your genes - even you have them in non-sexual organism (plasmids). If our gene (in an individual) changes with time, then maybe we can be immortal... But imagine acquiring different changes in genes across the body...

[magnemoe]

18 minutes ago, Kerbart said:

I read recently that researchers had managed to produce self-reproducing chemicals. One of the things they learned form their experiment, they said, was that death was essential for the evolution mechanism. Change was only possible if the previous generation went out of the way.

So with that in mind, perhaps it's built-in; species who die might, evolutionary, do better than the species who get stuck with "the old ones."

Think its more of an issue that in the wild the chance of becoming old is so low its little pressure to become older. 
Its an obvious benefit to continue to create new generations for a long time, however chance of living so long is so small other factors like avoiding getting hurt or sick is far higher. 
You can read survival statistic a bit off animals average lifespan, huge animals with no enemies like elephants get old, small plant eaters just live a couple of years. 

Cats are a bit weird, they are small but live long, it might be an effect of humans, an cat living near humans is far safer and vil live long.
Humans are a bit weird in that we live so long after stopping giving birth. Its no evolutionary pressure keeping you alive after this. 
Some think this is group evolution, having older people live longer let them help and teach kids freeing up the others to hunt and gather. 

[AngelLestat]

24 minutes ago, Kerbart said:

I read recently that researchers had managed to produce self-reproducing chemicals. One of the things they learned form their experiment, they said, was that death was essential for the evolution mechanism. Change was only possible if the previous generation went out of the way.

So with that in mind, perhaps it's built-in; species who die might, evolutionary, do better than the species who get stuck with "the old ones."

Evolution happens from the gene perspective.. no species..  in that case is really difficult to find what could be the benefic for the gene in have an autodestruction mechanism.. Help to their gene copies that "might" be exactly like him?   when in fact he is for sure that if he saves himself (gene) it has more chances to save that particular gene. But this strategic might have more sense in animals with higher number of childs which does not need the parent to take care of them, and maybe its death can provide them more resources (because there is more chances to have that specific copy of that self destructive gene in their child's and these to survive).
To see if one evolution trait has sense or not.. we just need to follow the chances that each individual gene traits has to spread or live. 

[mikegarrison]

48 minutes ago, Bill Phil said:

If the goal of life is to pass on genetic material, then immortality isn't necessarily a good thing to have. As long as our genes are passed, then does it matter if we die?

Exactly. The question to ask is, "what's in it for your genes"?

[peadar1987]

It probably also has to do with adaptation rate. Things that don't die and reproduce quickly overwhelm the environment. Things that don't die and reproduce slowly, well, fewer generations means mutations build up slower and adaptation doesn't happen so quickly. They then get outcompeted by something where the older generations die off and leave room for their offspring to play survival of the fittest.

[magnemoe]

37 minutes ago, mikegarrison said:

Exactly. The question to ask is, "what's in it for your genes"?

If you are able to reproduce longer you leave more of your genes. Problem is that you are unlikely to live long in the wild so even if immortal it would not matter much. 
Nature does an trade off here, long lived species tend to be large or well protected so they have few enemies. 
 

[magnemoe]

39 minutes ago, peadar1987 said:

It probably also has to do with adaptation rate. Things that don't die and reproduce quickly overwhelm the environment. Things that don't die and reproduce slowly, well, fewer generations means mutations build up slower and adaptation doesn't happen so quickly. They then get outcompeted by something where the older generations die off and leave room for their offspring to play survival of the fittest.

Rabbits don't live long and overwhelm the environment if they have no enemies. Probably faster than animals who live long, have few kids and take care of them. 
Large animals also work well, yes they have an issue with adapting to changes because low genetic drift. No they don't do well against human hunters but that is another issue. 

[PB666]

2 hours ago, WestAir said:

Pretty straightforward. So genetic traits mutate over time and the organism with the best traits survives. Since survival of the fittest is the name of the game, then the most long-living organism should have a fairly obvious advantage. Why hasn't organism immortality become a popular trait among complex organisms? I imagine the whole cause of the hayflick limit can naturally be prevented if the proper genetic mutation were to occur. (How hard can it be to replace telomers?)

We've had billions of years to overcome senescence and reap the benefits of biological immortality - so why hasn't this happened? It seems pretty straightforward that a species that doesn't have to contend with age-death would have a better chance of survival.

You are looking at the problem at the wrong perspective. To be certain there are microbes with an effectively zero mutation rate (at least at standard temperature and pressure, although they tend to live at higher temperature).

Start by going backwards in time to about 700 to 800 million years ago, so you have a period prior to the cambrian explosion where the earth goes through some rather dramatic environmental swings. It goes from hot greenhouse state to a cold state caused by the great oxygenation event. Simple fission for bugs works well, and we do see perfectly replicating creatures, cloning oneself is effectively immortality from a microbes point of view, up until something massive changes, then its what we call an evolutionary dead end. Eucaryotes get around this issue by exchanging gametes, simple enough we could have an exact copy of mother and father inside our genome, but theres a problem because the genes sort dependently on linkage groups. To solve this problem eucaryotes more or less have a recombination facility known as meiotic division (and its presteps). This cause the genes on linkage groups to sort semi-independently, but consequently to be realized it must also create a new, different, individual something that cannot be a clone. Having two copies now allows for a higher mutation rate, the mess gets sorted out by the F1 generation (selection). It does not have to be like this but it tends to be that case that parent one creates a meiotic cell and parent 2 the same, and they combine these into filial X (with two chromosomes of every type with no single chromosome exactly like either chromosome of the parents). IOW parent cannot carry on by cloning themselves by fission. This is a wildly successful group survival scheme for complex organisms.

So now you have progeny that are different and in selection with the parents, in a zero sum game, if parents cannot procreate at the rate of F1 then they are now consuming progeny resources, so selection does not favor immortality, instead it favors variation. There are other mechanisms, like balancing selection and heterozygous selection rates that favor diversity this allows populations to be older by showing more diversity than actually exists (offspring tend to select non-alike mates for certain critical traits like immunity). This has the benefit of allowing them to live longer and produce less progeny.

 

 

 

[Yasmy]

1 hour ago, YNM said:

We're not immortal because we reproduce sexually. Evolution can only happens in those cases, where you share your genes - even you have them in non-sexual organism (plasmids). If our gene (in an individual) changes with time, then maybe we can be immortal... But imagine acquiring different changes in genes across the body...

Evolution is not completely dependent on sexual reproduction. Evolution through mutation occurs in both sexual and asexual reproduction.

Second, females don't entirely reproduce sexually: mitochondria have their own genes, reproduce asexually, and are passed down from mother to daughter (and son) but not from father to child. Sperm don't contribute directly to the mitochondria history or evolution (other than assisting ova to mature into beings capable of reproduction). Some people jokingly call women immortal, because their mitochondria live on in their progeny. It's not too far fetched to say we're a symbiote of mortal and immortal cell lines.

[YNM]

1 hour ago, Yasmy said:

Evolution is not completely dependent on sexual reproduction. Evolution through mutation occurs in both sexual and asexual reproduction.

But asexual reproduction with mutation certainly won't occur in multi-celled organism without bad consequences... Even with those single-cell organism, they still sometimes share genetic information through plasmids, which helps spread new genes horizontally to produce totally new offsprings in the group.

 

1 hour ago, Yasmy said:

Second, females don't entirely reproduce sexually: mitochondria have their own genes, reproduce asexually, and are passed down from mother to daughter (and son) but not from father to child.

Well, that's organelles, no ?

[Vanamonde]

There are several factors at work. In addition to the things others have said: 

Genes which are more advantageous live to reproduce themselves. Since the parent can't acquire fundamental new traits during its lifetime, eventually, it's off-spring and grand-offspring (etc.) will out-compete it with their newer, more advantageous genes. So even if the parent didn't ever die of old age, eventually it would starve, or fall behind the rest of the herd and be the one the predator picks off, or whatever. Superior new generations continue while the primitive progenitor dies. 

Once an animal reproduces, it's nearly irrelevant to evolution because any new advantages it did manage to acquire after that would die with it and not be passed along. Therefore, there's little long-term advantage to the parent staying alive once the offspring are mature, so there's little evolutionary pressure for the parent to outlive its usefulness. And evolution seldom wastes resources developing something which has no utility. 

[fredinno]

5 hours ago, YNM said:

We're not immortal because we reproduce sexually. Evolution can only happens in those cases, where you share your genes - even you have them in non-sexual organism (plasmids). If our gene (in an individual) changes with time, then maybe we can be immortal... But imagine acquiring different changes in genes across the body...

I don't think that is possible.

3 hours ago, Yasmy said:

Evolution is not completely dependent on sexual reproduction. Evolution through mutation occurs in both sexual and asexual reproduction.

Second, females don't entirely reproduce sexually: mitochondria have their own genes, reproduce asexually, and are passed down from mother to daughter (and son) but not from father to child. Sperm don't contribute directly to the mitochondria history or evolution (other than assisting ova to mature into beings capable of reproduction). Some people jokingly call women immortal, because their mitochondria live on in their progeny. It's not too far fetched to say we're a symbiote of mortal and immortal cell lines.

Midiclorians Mitocondria are not really living though, even though they can reproduce. Neither are viruses.

[GeneralVeers]

Quote

Why isn't biological immortality a trait?

Because, and this will seem paradoxical at first glance, immortality is bad for the species.

If you're immortal, you will do one of two things: reproduce very slowly (or not at all) or very quickly overpopulate your environment, decimate the food supply, and starve to death as a species. If it's the first one, your species doesn't evolve, doesn't grow, doesn't improve. Everybody else does. And you get out-evolved by pretty much everyone else. It's pretty easy to guess where that ends.

When you get right down to it, Nature and Evolution aren't concerned with the happiness or welfare of individuals. There are many species whose individual members have very short lifespans, but those species as a whole do just fine.

[p1t1o]

Entropy.

[Kobymaru]

Lots of good answers already, but I wanna add this:

 

9 hours ago, WestAir said:

I imagine the whole cause of the hayflick limit can naturally be prevented if the proper genetic mutation were to occur. (How hard can it be to replace telomers?)

You're getting it wrong. Replacing telomers is easy, but the telomer shortening mechanism is there *on purpose*, and the purpose is to track the cell mitosis count. Too many divisions, cell dies. This is important for, you know, not having cancer.

 

9 hours ago, WestAir said:

We've had billions of years to overcome senescence and reap the benefits of biological immortality

It's the other way around. We didn't just "not overcome senescence", it took us long enough to actually *invent* senescence. Early organisms didn't know what death was, but by inventing death we out-evolved those.

 

[magnemoe]

3 hours ago, GeneralVeers said:

Because, and this will seem paradoxical at first glance, immortality is bad for the species.

If you're immortal, you will do one of two things: reproduce very slowly (or not at all) or very quickly overpopulate your environment, decimate the food supply, and starve to death as a species. If it's the first one, your species doesn't evolve, doesn't grow, doesn't improve. Everybody else does. And you get out-evolved by pretty much everyone else. It's pretty easy to guess where that ends.

When you get right down to it, Nature and Evolution aren't concerned with the happiness or welfare of individuals. There are many species whose individual members have very short lifespans, but those species as a whole do just fine.

This will work just the same if you have a short life and reproduce rapidly, see my example with rabbits. In rapid reproducing animals tend to have pretty frequent booms followed by dieoff.
Main issue is that animals in the wild live so dangerous its unlikely that they get old enough to die from it. 
 

2 hours ago, Kobymaru said:

You're getting it wrong. Replacing telomers is easy, but the telomer shortening mechanism is there *on purpose*, and the purpose is to track the cell mitosis count. Too many divisions, cell dies. This is important for, you know, not having cancer.

And this, limit cell reproduction limit cancer, yes you die because of this but you have an reduced risk of cancer. And chances to die of old age for most animals are very small. 

[peadar1987]

41 minutes ago, magnemoe said:

This will work just the same if you have a short life and reproduce rapidly, see my example with rabbits. In rapid reproducing animals tend to have pretty frequent booms followed by dieoff.
Main issue is that animals in the wild live so dangerous its unlikely that they get old enough to die from it. 
 

And this, limit cell reproduction limit cancer, yes you die because of this but you have an reduced risk of cancer. And chances to die of old age for most animals are very small. 

Animals don't die of "old age" that often, but they often die from not being quick enough, disease resistant enough, or perceptive enough, all of which are associated with ageing. Evolution is a statistical process, and if you are more likely to die the older you are, the degradation of cells is still a factor.

[magnemoe]

6 minutes ago, peadar1987 said:

Animals don't die of "old age" that often, but they often die from not being quick enough, disease resistant enough, or perceptive enough, all of which are associated with ageing. Evolution is a statistical process, and if you are more likely to die the older you are, the degradation of cells is still a factor.

True, but this is not an significant factor, an animal who would live longer would be able to have more offspring something who would be an benefit for the gene.
It don't happen so much since other factors like higher chance at survive childhood and getting an mate are far more important.