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

There is a vast different between effective waste management and wholesale regulated systematic deregulation. The first one is just a necessary feature of any physical system with an actual physical output. The second one doesn't make sense.

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

Controlled death is a sort of exaggeration here. Cell-suicide is not necessarily controlled. It happens all the time accidentally because you decided to smoke, to drink coffee, to expose yourself to some radiation, etc...

The point is that there is a colossal step between cell-suicide and programmed organismal death. Death may very well be virtually unavoidable for beings of our scale and complexity, but the idea that telomeres division or sexual reproduction is somehow what cursed us to death, which was popular in the early 90s and 2000s, is just going the way of the dodo.

The point is that there is a colossal step between cell-suicide and programmed organismal death. — Akanthinos

Good job I didn't claim that then. That level of eugenic control has only really become possible for human society. ;)

I was talking about the death of possibilities, the termination of development - the positive step of making the soma disposable so as to make the germ-line evolvable.

If you want to make some more simplistic reading of what I wrote, I guess I can't stop you.

Another way of looking at it is the lifecycle model of development - the three natural stages of immaturity, maturity and senescence.

When you are young and stupid, you also have degrees of freedom to burn. You can recover quickly from mistakes, repair any damage, as the body and mind are still in learning mode, not yet established in strong habits.

When you are mature, you have a nice healthy balance of plasticity and stability. You can still recover from perturbations and mishaps, but also you are pretty well efficiently adapted to your environment. You are set up structurally to be doing mostly the right thing.

But this habit-forming - this burning off of the plasticity to lay down confirmed wise habit - keeps on going. Eventually we become so well adapted to our immediate environment - more efficient, less energy consuming, in meeting our survival goals - that we then become more prone to catastrophic breakdown when that environment changes. We have spent all our recovery powers, all our plasticity, to achieve a really good developmental fit with out world. And then it changes on us,

If the whole population becomes a collection of wonderfully adapted old farts - then that works super well until, suddenly, unpredictably, it doesn't.

So yeah. I started with the accidental nature of death. Mostly we would say it is the world that terminates our usefulness.

But then deliberate death also slips into the picture - as the basis for accessing a wider range of complexity-dependent evolutionary possibility. Scheduled, or just statistically reliable, terminations become a useful thing.

I was talking about the death of possibilities, the termination of development - the positive step of making the soma disposable so as to make the germ-line evolvable.

If you want to make some more simplistic reading of what I wrote, I guess I can't stop you. — apokrisis

Bloody hell, how fucking otiose can someone be???

Bloody hell, how fucking otiose can someone be??? — Akanthinos

Yep. I was certainly wondering.

I was talking about the death of possibilities, the termination of development - the positive step of making the soma disposable so as to make the germ-line evolvable. — apokrisis

Well, apparently, moments ago, you were talking about structural complexity requiring controlled death. So you aren't have the most coherent of conversation, at the very least.

Organismal immortality does not prevent evolution.
Death did not evolve.
Death is not necessary for sexual reproduction, or vice-versa.

The A Contrario of these are the claims that you made in your post, and they were incorrect, and as usual you tried to deflect by writing a barely-related envolee lyrique.

Organismal immortality does not prevent evolution. — Akanthinos

You are talking right past my point again.

The immortality of the germ-line had to be physically separated from the mortality of the stem-line to achieve even basic multicellular complexity. And while stem cells can just keep growing - turning into whatever tissue they are being told to express by their surrounding mature cells - there is a general framework of regulation that is a kill switch on those possibilities.

The stem cells are stopped from producing the wrong tissues. They are told even when to stop producing. And then mature cells are regulated by similar collective signalling. You have apoptotic control.

So organismic-level immortality did prevent the evolution of complex structure. That is why a germ-line/stem-line dichotomy had to be evolved. The immortality had to be locked away in its own box. And then that made the soma disposable enough that it could become highly adapted as a system of specialised organs - none of which could survive on their own, but which might occasionally slip the leash of regulation to become cancers.

So it might not be the preordained death of an organism because some kind of genetic clock has ticked away the time to the appointed moment for a suicide. But the OP asked in what way might death be evolved as a practical advantage, and I was addressing the OP ... until you butted in.

These are the claims that you made in your post, and they were incorrect, and as usual you tried to deflect by writing a barely-related envolee lyrique. — Akanthinos

Since you had butted in, I thought I would cover off the senescence issue as well as regeneration/metamorphosis. It might have been of interest.

And your claims about what I claimed are plainly incorrect.

The immortality of the germ-line had to be physically separated from the mortality of the stem-line to achieve even basic multicellular complexity. — apokrisis

What immortality? Germ-lines can become extinct like anything else.

What immortality? Germ-lines can become extinct like anything else. — Akanthinos

Clearly the word you intended earlier was obtuse. It is my efforts to enlighten you which have proved otiose.

But if you do have any further interest in the biological arguments, try Nick Lane's The Vital Question. It deals with just this issue.

I think you're right in that there's a some kind of biological ''deal'' - immortality for specialization. So, stem cells specialize into specific tissue lines and lose their immortality. This allows for complex life to evolve.

In a way complex life (eukaryotes?) owes its existence to this trade off.

A year ago I saw this sci-fi movie (forgot the name) where they capture s star-fish like Martian life form whose cells are multi-functional e.g. the skin cells think, see, taste, smell, feel and multiply all at the same time. The cells are even able to contract like muscles.

Do you think that's possible - ''Omnipotent'' cells capable of any possible bodlily function and still able to undego cell division?

A year ago I saw this sci-fi movie (forgot the name) where they capture s star-fish like Martian life form whose cells are multi-functional e.g. the skin cells think, see, taste, smell, feel and multiply all at the same time. The cells are even able to contract like muscles. — TheMadFool

"Life". Awesome movie.

"Life". Awesome movie. — StreetlightX

The Flying Spaghetti Monster on drugs. :grin:

Do you think that's possible - ''Omnipotent'' cells capable of any possible bodlily function and still able to undego cell division? — TheMadFool

Cells are omnipotent in that they all carry around the same kitset of genes. But they become specialised in their expression of those genes so as to form specific functional structures like lung tissue or brain tissue. A higher level of intercellular signalling suppresses the generic genetic potential to create the specialised functionalities.

So it is the constraint on that generality that leads to the complexity of a body with an organ system. That makes it "impossible" to have generalist cells that are also, at the same time, specialists at everything. The specialism is what emerges due to the cell being constrained within a context of collective action. The functionality is a property of the higher level of organisation and so cannot inhere in the cell itself.

The functionality is a property of the higher level of organisation and so cannot inhere in the cell itself. — apokrisis

That's sad to hear. Probably because it's the truth.

This has all been very interesting, but I wonder if anyone could tell me just why anyone should want to live forever, taking up all that room and getting in the way of sensible development. What on earth is that good about going on and on? That is what bores do.