Death, why?

[aguy2]

What possible evolutionary advantage could be gained for an organism by dying?

 

aguy2

[Deified]

Evolution cannot occur if things can't die. Not to mention that it's not a trait developed through evolution, cells decay.

[fairychild]

can you imagine how the world would look like if no organism had ever died in the earth's entire history?

[Crash]

what would the use be in telomeres if cells (basically a person) wouldnt die?

[Martin]

What possible evolutionary advantage could be gained for an organism by dying?

 

aguy2

 

Great question! Dying of its own accord confers a clear advantage (of speeding evolution) and it developed because of that.

 

Early forms of life didnt die-----like amoebas that just keep on dividing.

 

Death has to be programmed into cells to make them age, there is some biological built in clock. I dont know how it works. maybe Crash does.

 

Some species "invented" death and this gave them an advantage, they evolved faster so they won out over the others.

 

Death and Sex are two of MotherNature's inventions that may have evolved around the same time. A species with sex and death has great advantages because it can evolve faster:

Sex lets the genes shuffle around and mix things up and try different combinations. And Death clears the decks and makes room for the new combinations of genes to be tried out. The old combinations die and make room for the new.

 

I hope other people answer because I am not an expert in this.

Maybe Crash can explain how cells manage to have this mortality clock that makes them age and die. Cause amoebas dont have it, they stay young.

[reverse]

Because, the candle that burns twice as bright lasts half as long.

 

Creatures in the deep cold cold artic sea live for ages, people started to notice this when a bone harpoon was found in a recent whale kill.

 

A few creatures on earth do not age, tortoises are one example I think.

 

Would you have it that we reached puberty then stopped the aging algorithm.

that may be possible.

 

nice for the living, not so good for the yet to be born.

[reverse]

just had a thought on this.

 

because it's smarter to carry improvements in a creature in the genetic code rather than in learned behaviour.

 

the genetic improvement is far more durable, and more in sync with the core rules of evolution.

 

Think for example of a really old experienced creature competing for the same resources with an inexperienced but genetically improved younger creature. One of the prime control factors of evolution would blow a gasket.

[reverse]

and another.

 

 

How about this , it may be a simple energy equation.

 

It may take less energy to start a new creature than keep repairing an older one.

Therefore the population that expresses the expiry date characteristic will win over the one that does not.

Because for the equal units of energy, the "expiry" type population gets more biomass.

 

huh..what do you think?

[Auburngirl05]

I would say to avoid progressive senescence, which will eventually lead them to more vulnerability to disease, predators, etc and result in death anyway.

[-Demosthenes-]

I don't think we are talking about death necessarily, organisms in the beginging did die, they just didn't age and die from old age, as some do now.

[Sorcerer]

Ok, I think alot of the people in this thread have misinterpreted evolution, there seems to be some underlying idea that genes can think and know what is the best option for their survival, this is not so, genes just "do" and when they happen upon the best option for survival this one wins out.

 

Now as for death, genes themselves are eternal as long as they have a means of replication, they do not care what happens to their host, in fact they can't care. Instead they program their host so that they have the ability to spread and multiply the genes, because this is the most successful method of replication.

 

Martin I think mentioned that amoeba are immortal, this is not so, their genes are immortal, except for random mutation errors. The original "mother" amoeba will die eventually as oxidation and other enviromental effects take its toll on the cell. The "daughters" however will have fresh cells which will last longer, these too divide and over time the original amoeba is no longer present, but its genes may be (provided no mutation).

 

Since it is far easier for genes to build a new host than prolong the life of its present one eternally, death is the most successful option. I think reverse had it right in his second post.

 

Genes that don't die are successful, these are the ones that replicate eternally, the host for the genes is only a vessel required untill replication has taken place. The more replication, the more successful; however once two progeny have been produced if the cost prolonging the life of the original host outweighs the cost of its progeny replicating then immortality will be less successful; since it is this way it seems that immortality is a less successful route (sorry for the circular argument there).

[reverse]

this death thing.

It would not be that easy to avoid it.

 

what might be under consideration is a person getting to puberty, then having the ageing genes switched off.

so you would stay young for eighty years.

 

-but subject to death by any number of ways.

fire, blood loss and so on.

 

I think the real answer to your question is in the sheer number of processes that it takes to keep an organism alive.

 

the question shouldn’t be, why do we die,

but rather

how on earth is the body so good at repairing itself that we get to live as long as we do?

[reverse]

ok ok I think I really have got it figured this time.

 

wasn't it normal for people to die at about twenty throughout most of mankind’s history.

 

they were either eaten or became lame or sick, because the environment was so severe.

 

so why on earth would you install an industrial strength repair system into a creature that had a statistical survival period of about twenty years.

you know nature doesn’t waste, so it would be sensible for it to just divert that extra repair capability elsewhere.

[Sorcerer]

I dont actually think there are genes responsible for aging, it is more a consequence of the expression of the genes for cell division, the shortening of the telomeres everytime a cell divides puts an upper limit on the number of cell divisions. There is however an enzyme, telomerase, which restores telomeres in eggs so they are fresh for the next generation, the consquence of using this on adults however would probably be cancer. Another factor in aging is oxidation and mutation of somatic genes, the cell has alot of genes responsible for fixing our DNA, however it is not perfect and mutations in these genes themselves lead to cancer.

 

There are some people with a hereditary condition that makes them appear to age at an accelerated rate, this may be a good place to look if you want to find the genes responible for aging. However I think you will find that it is rather the genes responsible for youth that are affected.

[Sayonara]

I understand the point you were trying to make, but it's not really accurate to call genes 'immortal'.

[Sorcerer]

Well pseudo-immortal, as far as there is an environment to contain them....... e.g. the earth/universe. And barring extinction/mutation.

 

Or is ur problem with the use of a personified word? Perhaps a synonym would be better, eternal?

 

Or is it because the gene itself is always replaced, and it is the information that is eternal?

[Sayonara]

It was the extinction part that did it for me.

 

Given a long enough timeline, all genes will become unrecognisable or extinct.

[reverse]

question.

 

are any of the cells that were alive in a person at two months old, still there at sixty years.

or have they all been replaced?

[reverse]

I just thought of shark teeth compared to ours.

they have rows of them all revolving to the front, as one set wears out.

 

ours do the replacement trick once only, then stay.

 

while oxidation and mutations etc etc are interesting factors, if mother nature found it needed to make a creature live for two hundred years at peak operational efficiency, then it would construct systems to combat any one of those factors you mentioned.

 

no the answer to this question is not in the physical limitations of replication systems. it's in the strategy that is served by limiting a lifespan.

[Sayonara]

In our case I don't thin you can really call it replacement; the two sets are distinct and differ greatly.

[aguy2]

There is a hot new area of cellular biology they are calling 'apoptosis', that is concerned with internally programmed cell death, deliberate cell suicide, and how this process confers evolutionary advantages during an organism's life cycle. Here are a couple of sites: http://magazine.uchicago.edu/9606/9606Celldeath.html and http://www.ucalgary.ca/~browder/apoptosis.html

 

I am still having problems on how multi-celled organisms developed such multi-faceted and intricate mechcanisms to insure the death of the individual so soon after such organisms developed during the 'Cambrian Explosion'.

 

aguy2

[coquina]

There surely would be one if all organisms were immortal. Also death is the means that returns nutrients to the system, except in the case of humans, where people think they have to have a corpse embalmed or burned.

 

Maybe somebody ought to buy a huge chunk of desert and establish a cemetery there where people who would like to replenish the earth with their bodies could be buried, without embalming, caskets, or vaults.

[Sayonara]

If nothing ever died naturally, ecology would be a hell of a lot more violent.

[-Demosthenes-]

Maybe somebody ought to buy a huge chunk of desert and establish a cemetery there where people who would like to replenish the earth with their bodies could be buried' date=' without embalming, caskets, or vaults.[/quote']

Maybe we could invent a people shreader and shread dead people and spread them in the weat fields!

[reverse]

say if all the cells in our body get replaced by the time we reach sixty, how are early memories maintained?

brain cells are cells as well arent they?