what does the Theory of Evolution say about death? — TheMadFool

If you propagate - i.e. if your sperm cells win - then you outwit it. You personally will die but your line will live on. Beyond that, there is no ‘why’.

There was a great article by Peter Hoffmann in Nautilus a little while ago, weighing up the different takes on why we die (or age, rather). He does a nice job of bringing alot of them together:

"The scientific literature is full of explanations for aging: Protein aggregation, DNA damage, inflammation, telomeres. But these are the biological responses to an underlying cause, which is accumulating damage through thermal and chemical degradation.... If this interpretation of the data is correct, then aging is a natural process that can be reduced to nanoscale thermal physics—and not a disease."

The whole article is worth a read, it's pretty breezy, and relates quite nicely to the OP. As to weather death 'evolved', well, no, death is a condition of evolution, so cannot have evolved; This is a logical/defintional point. Also, the question mixes up levels up analysis: death is what happens to individual organisms, evolution is what happens to species and their environments (the correlate of the latter is extinction, not death).

The whole article is worth a read, it's pretty breezy, and relates quite nicely to the OP. As to weather death 'evolved', well, no, death is a condition of evolution, so cannot have evolved; This is a logical/defintional point. Also, the question mixes up levels up analysis: death is what happens to individual organisms, evolution is what happens to species and their environments (the correlate of the latter is extinction, not death). — StreetlightX

You're right. Seems I mixed up death with extinction but there is an analogy to be had. Don't you think?

After all death on a large scale is the mode of extinction.

"The scientific literature is full of explanations for aging: Protein aggregation, DNA damage, inflammation, telomeres. But these are the biological responses to an underlying cause, which is accumulating damage through thermal and chemical degradation.... If this interpretation of the data is correct, then aging is a natural process that can be reduced to nanoscale thermal physics—and not a disease." — StreetlightX

I guess there's a difference between natural death (old age) and premature death (infection, trauma, etc.). It feels right not to consider the former a malady but not the latter.

However this doesn't sit well with the general perception of death. Most people prefer to live long and, if possible, indefinitely. So, despite science explaining death as a natural process we still have, perhaps a psychological propensity, an impression that ALL death is unnatural.

According to Peter Hoffmann (Nautilus), death is just the laws of nature progressing to their inevitable ends. That means his belief is a mix of the two scenarios I described in my OP. Death has both genetic and environmental components. We die because it's programmed in our genes and also because we succumb to environmental stresses.

What about cancer cells? Dysfunctional though they are they seem to be immune to both genetic signals and environmental stress. Immortality is possible. We don't really have to die even within the context of, I quote, "thermal and chemical degradation". This seems to suggest that it's the environment that has the greater say in death and not our genes which are fully capable of immortality.

If you propagate - i.e. if your sperm cells win - then you outwit it. You personally will die but your line will live on. Beyond that, there is no ‘why’. — Wayfarer

Why not? There must be a reason we die, right? Death is the anti-thesis of life and yet it appears that it's programmed into our cells. That's paradoxical and I'd like to question it.

What about cancer cells? Dysfunctional though they are they seem to be immune to both genetic signals and environmental stress. Immortality is possible. We don't really have to die even within the context of, I quote, "thermal and chemical degradation". This seems to suggest that it's the environment that has the greater say in death and not our genes which are fully capable of immortality. — TheMadFool

Cancer is fascinating and terrifying because it is literally a kind of superabundence of life itself: life without the limits that normally constrains and, in the last analysis, sustains life. Cancer is pathological life that is indifferent to limits: it's only imperative is to propagate, irrespective of whether this propagation will kill off the very environment that sustains it. The sociologist Melinda Cooper has a great discussion of this, in which she cites the work of Aurel Kolani:

"The specific sickness of cancer lies in the metastasizing overproduction of life rather than its simple negation. If cancer kills, it is not so much through a direct decomposition of the organism, as an extortion of the vital life force of organic life (cellular division), which it deflects from all ends — other than its own accumulation. There is overproduction of life, writes Kolnai, when the generative processes of growth, reproduction, and regeneration escape the boundaries of organic space and time." (Cooper, Life as Surplus)

Cancer lifes you to death. But the point is that those boundaries are what, at the end of the day, allow life to continue. Cancer, precisely because it does not respect those boundaries, ends up putting an end to life. So the so-called immortality of the cancer cell is a double-edged sword: it buys its immortality at the price of... life (which should tell you something about how life and death cannot be as cleanly separated as I think you'd like).

Cancer lifes you to death. — StreetlightX

:up:

So the so-called immortality of the cancer cell is a double-edged sword: it buys its immortality at the price of... life (which should tell you something about how life and death cannot be as cleanly separated as I think you'd like) — StreetlightX

"how life and death cannot be as cleanly separated as I think you'd like'' - interesting!!

You mean death is a part of life itself?

I also thought so but the direction modern medical research is going I think biologists don't think so.

All medical research is about delaying or even completely stopping the aging process. The business, so to speak, is to help people live longer and fuller lives.

I think a time will come (not any time soon) when we can overcome death. I don't know if that's a good thing or not but the trend in medical research suggests such a goal.

I think much of the current perception about life is, even now, very much outdated. I don't like saying his but religion has a lot to do with it. Religion, playing on our deeepest fears and hopes, forces us to cling to ancient notions of life. For instance, Buddhism believes life is suffering, an idea that seems preposterous now that life spans have increased and modern medicine has almost conquered pain.

The future will surely(?) be radically different from the present. Life could be pleasurable, even to the extent that we could create heaven on Earth.

You mean death is a part of life itself? — TheMadFool

I'm not sure talk of 'parts' and 'wholes' is very appropriate here; I'd perhaps like to think about it in terms of Kant's dove - Kant imagined a dove which, feeling the resistance of air on its wings, figured that it would be much better off without the air getting in its way. But you'd know how that story ends.

Loren Eiseley thought it did. In The Firmament of Time, he argues it became natural.

So, what does the Theory of Evolution say about death? — TheMadFool

Once you are past the age of reproduction, evolution doesn't care about you at all. That's how it works. It only matters what you pass off to your offspring. Why would evolution, the world, anything, anyone, care if you lived forever?

Hey my first post..... I think of life as an all encompassing thing, so the death of a life form is not the death knell for life itself.

Makes me think the first organism (life form) had to be adapted to the environment without ever evolving. What an incredible stroke of luck that must have been. I mean how does non living material evolve to produce a life form adapted to the conditions existing at that time? I'm thinking there was an incredible amount of proto-life under construction prior to that first organism (one that could eat, reproduce, store energy, evolve etc) emerging from the primordial ooze. There could have been no death before life. With its environment in a state of flux it appears as if death for the life form did indeed evolve....maybe.

I'm not sure talk of 'parts' and 'wholes' is very appropriate here; I'd perhaps like to think about it in terms of Kant's dove - Kant imagined a dove which, feeling the resistance of air on its wings, figured that it would be much better off without the air getting in its way. But you'd know how that story ends. — StreetlightX

Be careful what you wish for, especially when you lack wisdom. Right.

Perhaps death is necessary. I take it you mean that. But what if it's contingent? What if?

Loren Eiseley thought it did. In The Firmament of Time, he argues it became natural. — tim wood

If it evolved then death is necessary as opposed to contingent. The reason(s) why would be interesting to know.

Why would evolution, the world, anything, anyone, care if you lived forever? — T Clark

I'm under the impression that evolution is about survival - life. If death is necessary for survival (paradox) then it's interesting to know why.

With its environment in a state of flux it appears as if death for the life form did indeed evolve....maybe. — Codger

Yes, in the dark we must fumble. I guess somethings are unknowable.




I read in biology that cells undergo what is called apoptosis which basically means suicide. Cells do this when they sustain irreparable damage to their chromosomes (thus preventing cancer or viral infection) or if other crucial cellular mechanisms fail.

What do you make of that?

I mean how does non living material evolve to produce a life form adapted to the conditions existing at that time? — Codger

Welcome to the forum. If you're interested, there have been some really good scientific discussions of abiogenesis, how life developed from non-living material, on this forum. The one I remember is called "On the transition from non-life to life."

I'm under the impression that evolution is about survival - life. If death is necessary for survival (paradox) then it's interesting to know why. — TheMadFool

I've rethought my response a bit. The general principle is still the same - if a characteristic, e.g. longevity, doesn't impact reproductive success, it will have no impact on evolution by natural selection. So, once a person leaves their reproductive years, natural selection becomes blind to their longevity. I rethought my response because, historically, men can continue fathering children longer than than women can bear.

Loren Eiseley thought it did. In The Firmament of Time, he argues it became natural.
— tim wood

If it evolved then death is necessary as opposed to contingent. The reason(s) why would be interesting to know. — TheMadFool

Well, Eiseley opposed natural to unnatural. The idea is that death was always because of something. You died because you were bad, or had bad luck, or were weak, or some such thing. Maybe the Volcano god was angered by the inferior quality of the virgins you sacrificed.

I do not remember (it's not in front of me - I haven't read the essay in a while) when death became natural, according to Eiseley, but it's relatively recent.

finite life-span — TheMadFool

It would seem that everything has a finite life span, a temporal state of affairs. Would evolution or creative evolution (Bergson) make sense if permanence or unending growth were the case? A transition from non-living material to living does not cancel entropy, or a global homeostasis. Death is a necessary condition of procession.

"If this interpretation of the data is correct, then aging is a natural process that can be reduced to nanoscale thermal physics—and not a disease" — StreetlightX

But there are some organisms that don't age, and our reproductive cell line is immortal and doesn't age. So aging is not necessary, at least for some types of cells, and there is ongoing research showing some promise into slowing or even stopping the aging process in various animals, including humans.

But there are some organisms that don't age, and our reproductive cell line is immortal and doesn't age. So aging is not necessary, at least for some types of cells, and there is ongoing research showing some promise into slowing or even stopping the aging process in various animals, including humans. — Marchesk

I remain sceptical. After all, germ cells are not organisms, and the reason that they don't age is that they - exactly like cancer, actually - remain undifferentiated, retaining their pluripotential so they may turn into other cells. And organisms just are differentiated beings (among other things).

I remain sceptical. After all, germ cells are not organisms, and the reason that they don't age is that they - exactly like cancer, actually - remain undifferentiated, retaining their pluripotential so they may turn into other cells. And organisms just are differentiated beings (among other things). — StreetlightX

The Water Hydra is a little creeper that seemingly doesn't age at all. It's stem cell can apparently self-rejuvenate as needed without the cap to division that apparently affect almost all other cellular life.

https://en.wikipedia.org/wiki/Hydra_(genus)

Very cool. I wonder how it 'works'.

The Water Hydra is a little creeper that seemingly doesn't age at all. It's stem cell can apparently self-rejuvenate as needed without the cap to division that apparently affect almost all other cellular life. — Akanthinos

So what exactly, are it's limits?

Well, for the longest time, it was thought to be the length and substraction of the telomeres, small tubular "hair" located at the end of chromosomes, which would shrink after every cell-division. When the telomeres are too small ; no more cell-division.

The number of cell-division possible in humans is called the Hayflick limit, and stands for 40 to 60 cell-division before senescence.

I can't find many mentions of living beings with the same degree of never-ending morphallaxis as the Water Hydra, but there are quite a few animals in which the process of senescence is negligible, to a degree which makes us long-lived humans look like ephemerals. A Proteus is a form of worm/salamander that has been observed to go to 200 years old. Clams have been found to go up to 500 years old. And sharks can grow over 400 years old.

I've rethought my response a bit. The general principle is still the same - if a characteristic, e.g. longevity, doesn't impact reproductive success, it will have no impact on evolution by natural selection. So, once a person leaves their reproductive years, natural selection becomes blind to their longevity. I rethought my response because, historically, men can continue fathering children longer than than women can bear. — T Clark

But reproduction seems to be related to death. Organisms can't survive death due to chemical/physical degradation and so reproduction does two things:

1. Replenishes the pool with younger individuals who must go through the entire process again

2. Gives an opportunity for mutations to occur; thereby giving life the chance to adapt to changing environments.

Look what happened to the dinosaurs. The natural process of adaptation was just too slow with respect to catastrophic change in the environment and so they died out. I'm only guessing here but if they had longer life spans (ceteris paribus) they could've survived the asteroid impact. Right?

death became natural — tim wood

Have a read above. It's a chicken-egg problem. Did reproduction evolve because we die or do we die because of reproduction. I mean reproduction seems to be a way for life to survive death and, taken another way, death seems to make space for the new generation.

Death is a necessary condition of procession. — Monitor

Why? It is a paradox isn't it? Death is necessary for life. Afterall they're diametrical opposites.

I think your problem is, you're seeking a naturalistic answer to a metaphysical plight. It is true that humans are perplexed and terrified by the prospect of mortality - that has always been the case. Arguably that is the very fear that religions have sought to assuage; after all, the premise of Christianity is 'life everlasting'.

Every progress in evolution is dearly paid for; miscarried attempts, merciless struggle everywhere. The more detailed our knowledge of nature becomes, the more we see, together with the element of generosity and progression which radiates from being, the law of degradation, the powers of destruction and death, the implacable voracity which are also inherent in the world of matter. And when it comes to man, surrounded and invaded as he is by a host of warping forces, psychology and anthropology are but an account of the fact that, while being essentially superior to all of them, he is the most unfortunate of animals. So it is that when its vision of the world is enlightened by science, the intellect which religious faith perfects realises still better that nature, however good in its own order, does not suffice, and that if the deepest hopes of mankind are not destined to turn to mockery, it is because a God-given energy better than nature is at work in us.

Jacques Maritain, http://thomasofaquino.blogspot.com.au/2017/07/god-and-science.html

I'm sure many have seen the Martin Hanczyk TED TALK re proto-cells . He shows how a simple molecular arrangement can produce life like attributes to what is essentially a chemical droplet. Great viewing if you've never seen it.

All the photo-cells in the experiments eventually run out of energy. I sat there wondering if these droplets were actually alive, even if for a few seconds? And do they die when energy is depleted and the chemicals return from the biochemical state to the physiochemical? If there are limits to a lifetime then I see no reason for a few seconds to be excluded from any chronologic scale that records lifespans. If proto-cells were alive then I think their dying played no role in evolution other then ensuring the organism's remains were available for recycling.

Very cool. I wonder how it 'works'. — StreetlightX

One fact that is interesting is that most other Hydrazoa (the larger family to which the water Hydra belongs) have a latter state as a polyp. The Hydra, in comparison to other members of it's family, never reaches full maturity. It's not a larval stage, because it can reproduce sexually and asexually, but I've always wondered if the Hydra didn't "trade in" ever reaching it's maturity stage in order to keep the super-morphallaxis that it has in earlier stages.

So, what does the Theory of Evolution say about death? — TheMadFool

Death has both genetic and environmental components. We die because it's programmed in our genes and also because we succumb to environmental stresses. — TheMadFool

Yes. The theory is that evolvability itself evolves. If you want to achieve greater biological complexity, there is an advantage in dividing things sharply between a mortal body and an immortal germ-line.

So the reason is to allow evolution to access the possibilities of greater structural complexity. Like sex, it had to happen to allow the step from simple bacteria to complex multicellular organisms.

So sex and death do go together.

Bacteria are messy analog creatures. They are promiscuously sexless - forever swapping gene kits even across so called species boundaries. And they are immortal - forever dividing unless hit by some external accident.

But eukaryotes had to create greater digital order. They had to make gene recombination a definite act - a sexual act that divided the flow of evolutionary history into a distinct before and after. And the same for death.

Or rather, it is more subtle. Multicellular organisms needed to separate their immortal germ-line from their developing bodies so that they could start to construct themselves from specialised tissues.

The germ-line - the connecting thread of evolutionary history - had to be tucked away in the gonads or ovaries to allow the other cells get on with their job of turning into lungs, kidneys, brain, muscle, or whatever kind of tissue was their developmental terminus.

So really, the death is the death of alternative developmental possibilities. You can't have lung tissue that wants the autonomy to breed more lungs. Lung tissue that does that is what we call cancer.

But then having specialist reproductive organs - the gonads and ovaries - introduces another problem. As they age, they do accumulate inevitable damage and become too prone to bad mutation.

Now germ-line and stem-line are separated so that one can produce variation while the other avoids it - the stem-line cells just continuing to express the programmed potential to be some kind of tissue like lung. But still, the variation via chromosome recombination is quite different - more tuned and selective in the traits that get exposed to the world - than the kind of brute damage that aging might cause.

So death is an evolved outcome, if a little more indirectly than sex. It is already a de facto presence in the very fact that stem cells are pre-programmed to undergo some certain number of cell-divisions and then - forever - stop. Once our lungs and brains and muscles achieve their proper developmental size, the body is already "dead" so far as its possibilities in that direction goes.

Simpler animals like newts and worms can afford to regenerate limbs and tails. But that stem cell level freedom had to end for good evolutionary reason if nature wanted to access more complex structural possibilities.

So metabolic wearing out is a big reason for death. That is one consequence of achieving complexity - more stuff to go wrong. But also the division of labour - the split between immortal germ-line and disposable soma - is a necessity for achieving complexity of organismic structure.

The lungs can't be allowed to have the ability to live on - spawn away, reproducing themselves - even after the kidneys are shot. The genetics must remain a package deal, tucked away safely, as far from metabolic degradation as possible. The body must perish as a whole so that the immortal part of the business can do its thing of being the continuous historical thread.

So sex and death do go together. — apokrisis

Again, the fresh water Hydra is a sexually reproducing animal that is virtually immortal. And there are plenty of animals who'se cells show heightened morphallaxis that have more or less the same putrefaction process that we have.

If death has evolved, it has stopped evolving a long time ago, much before complex sexual reproduction was evolved.

But it is also true that hydra depend on apoptosis, or programmed cell death, to rein in what would otherwise become runaway tissue growth. So death in this form become a necessity of the most simple metazoans.

The highly conserved morphological features of apoptosis suggest that it is under genetic control...

[Hydra] budding is dependent on feeding: well-fed polyps produce roughly one bud per day; starved polyps cease to form buds after 1–2 days. This striking dependence of budding on feeding is not due to a change in cell proliferation, as initially anticipated, but rather to apoptosis...

In reflecting on possible scenarios which might have led to this close association of apoptosis with metazoan evolution, we are impressed by the need to reduce cell-cell competition in multicellular tissues....

https://academic.oup.com/icb/article/45/4/631/636419

So yes. Simpler animals can afford the luxury of regeneration and metamorphosis. They can recycle cells as the raw material to remodel their structure.

But it is genetically controlled death - the evolution of death as a further now conclusive stage to life - that shows its face even in hydra. Deliberate death was the step underpinning evolutionary access to greater structural complexity.

But it is also true that hydra depend on apoptosis, or programmed cell death — apokrisis

Well, yeah, but to be fair, so does all form of complex cellular life. All cells are susceptible to cell-suicide if they are exposed to the proper stress value. And I don't think you should read too much "programmed
degradation" into it. The stress vectors which lead the cell to suicide are, notably, the same type of stress which may lead into cellular deregulation and then into cancer.

There is definitely a "cellular death management" function in all living beings. I don't think sufficient homeodynamism for anything else but the simplest vesicle could emerge without it. This doesn't mean that organismal death is itself pre-programmed.

Well, yeah, but to be fair, so does all form of complex cellular life. — Akanthinos

Wasn't that my point? Structural complexity depends on controlled death. And hydra are already complex enough for that to be a factor.

This doesn't mean that organismal death is itself pre-programmed. — Akanthinos

Again, it is an evolutionary story. If complex structure depends on controlled death, then control over that death will become increasingly a feature.