why don't we live forever

[unipidity]

Evolutionary advantage. It is 'fitter' to reproduce and then die. Too many cell divisions increases the likelyhood of cancer.

 

[JonB]

That is why the government has black projects underway exploring methods of weeding out those less desirables from existence through chemical contrails like the ones trailing behind jets, and by chemicaly altering flu and military vaccinations so after one reaches physical peak, the person becomes frail and sickly, dying a horrible death.

That's not the governement. That's the Grays (it was a Repton idea, but the Grays have the technology).

 

[Farmer]

ReiAyanami:

Well, I'm assuming that's true, since you say so, but what sort of program would you need to interpret that data? A "Brain Emulator"?

unipidity:

Well, you're not gonna die from cancer, if you were immortal that is. Its hard to imagine.

 

[Gibsons]

Imnsho, unipidity is right. DNA replication machinery has a certain error rate, and DNA repair mechanisms are less than perfect. So just in theory, there's some number of replications at which oncogenic mutations becomes highly probable or even inevitable. Old people are far more likely to get cancer than young people.

Note that in some models of ongogenesis, there are two steps, "immortalization" and "transformation." Cells that can replicate forever (immortalized) are, by this standard at least, half way on the road to cancer. Note that this all is a gross generalization - some types of cancers seem to need only two (or maybe even only one) genetic "hits" while others need more... and not every genetic "hit" easily falls under the category of transforming or immortalizing.

 

[syconub]

Originally posted by: zakee00
yes, if everyone lived forever, then the following would probably happen:
1. we would have advanced farther technologicly. einstein, etc would still be alive ..but
2. the earth probably wouldnt be habitable right now, lack of resources. BUT...
3. we might have developed technology to go to mars and live there!!! or...
4. we might not have...and we all die
5. wait...we are talking about people living forever..SOOOOO
6. the earth becomes a GIANT pile of bodes that can never die!!! we just keep piling up, and reproducing!!!
this could go on forever, its all speculation.

OMFG SOYLENT GREEEEEN!~~~~~~~LO0o0o0o0o0o0o0o0ol

 

[Farmer]

Note that in some models of ongogenesis, there are two steps, "immortalization" and "transformation." Cells that can replicate forever (immortalized) are, by this standard at least, half way on the road to cancer. Note that this all is a gross generalization - some types of cancers seem to need only two (or maybe even only one) genetic "hits" while others need more... and not every genetic "hit" easily falls under the category of transforming or immortalizing.

I can't agree more, if you're saying that the immortalization of man goes against the "natural order", for lack of better words, of things. Nothing immortal exists.

 

[Kalessian]

I don't see why someone immortal can't exist. If every aspect of genetic material was fully understood, couldn't it be rewritten to include immortalized cells AND rewritten to include perfect DNA replication processes?

I mean, if you knew EVERYTHING about all of the genomes, then as problems arrise(that somehow weren't planned for) they could be fixed by rewriting the fault and starting over, right?

Ignore the problems of applying the new DNA.

I'm just trying to say that theoretically an immortal human can exist.

 

[Gibsons]

I can't agree more, if you're saying that the immortalization of man goes against the "natural order", for lack of better words, of things. Nothing immortal exists.

I didn't mean to imply quite so much philosophically, though I probably did in my fondness for puns... anyway, immortalization is a defined property of cells in the jargon of modern biology... and most (if not all) cancer cells are immortal in this context. But not all immortal cells are cancerous. Rather, the property of being immortal seems to be a prerequisite to being cancerous.

I don't see why someone immortal can't exist. If every aspect of genetic material was fully understood, couldn't it be rewritten to include immortalized cells AND rewritten to include perfect DNA replication processes?

I mean, if you knew EVERYTHING about all of the genomes, then as problems arrise(that somehow weren't planned for) they could be fixed, right?

hmmm....

offhand there are a few issues, first one I can think of is that the bases in DNA spontaneously degrade. ie, for no predictable reason, they'll do a first-order reaction and become something else. Ionizing radiation could do the same thing. DNA repair processes typically fix such problems by identifying the damaged/altered base and correcting it to the complement of the base on the complementary strand. eg, a "T" spontaneously degrades, a very big and complicated set of proteins recognizes the damage and looks at the "A" on the complementary strand and replaces the damaged T with a normal T. Given immortal timelines, eventually you'll get two lesions both bases... so the repair machinery has nothing to compare to*. I suppose the answer to that would be to make DNA repair machinery that would recognize and correctly repair damage independently of the complementary strand. offhand I guess that might be possible, but I'd have to look at the chemistry for a while and even then I wouldn't be too confident in my answer. so um... I guess I took a long time in saying you could be right for all I know.

* There's an interesting (to me anyway) story regarding cytosine ("C" in the DNA code). When it's placed in front of a G, it gets methylated (in vertebrates iirc) and becomes much less stable (the time scale for the stability isn't significant for a single individual, but is for evolutionary time scales). The methylated C will spontaneously deaminate, and the repair machinery changes it to a T (iirc). For this reason the dincucleotide C-G is hugely underrepresented in mammalian genomes, much much less that the 1/16th one might expect.

 

[unipidity]

Re 'perfect' replication- ultimately we are dealing with a chemical process subject to uncertainty and true randomness. Its impossible. You can get arbitarily close, to reduce the process error to 0, but the quantum error will remain- as with, say, weather prediction.

I thought the question was why we hadnt *evolved* to be immortal. I have no doubt that in a few hundred years time of uniterrerupted technological advance, we could produce a fully computerised human with no wasteful metabolism. A brain in a vat, so to speak.

 

[Farmer]

Gibsons:

Yes, but cancers still die when there are no resources left to continue mitosis (in humans, when the host dies). Having something that simply will not die no matter what is quiet difficult to imagine.

 

[Looney]

Here's an interesting tidbit.. did you know all creatures on this planet, live approximately the same number of heartbeats? Which is 1 billion. So a rat may only live a year, it's heart beats much faster, and in the end, about the same number as us.

 

[Kevin1211]

Originally posted by: Hardcore
Here's an interesting tidbit.. did you know all creatures on this planet, live approximately the same number of heartbeats? Which is 1 billion. So a rat may only live a year, it's heart beats much faster, and in the end, about the same number as us.

that seems really interesting indeed. Do u have a link or a source that supports that??

 

[Gibsons]

http://www.ncbi.nlm.nih.gov/en...6546&dopt=Abstract

 

[sundev]

Originally posted by: Hardcore
Here's an interesting tidbit.. did you know all creatures on this planet, live approximately the same number of heartbeats? Which is 1 billion. So a rat may only live a year, it's heart beats much faster, and in the end, about the same number as us.

The 1 billion heartbeats thing isn't even true for humans. Take someone with an average heartrate of say 75 bpm. That's 4,500 beats per hour, 108,000 per day, and 39.4 million per year. Average lifepsan of 80 years makes that 3.1 billion heartbeats, not 1 billion.

And each animal living the same number of heartbeats isn't true either. For example, whales have a very slow heartbeat, but they don't live for long periods of time. Take the Blue Whale. It only does about 8 beats/minute, which is roughly 9 times slower than humans. But they don't live 9 times longer than humans -- their lifespan is only 80 years (same lifespan as humans). That means Blue Whales only do about 8*60*24*365*80 = 336 million beats in their lifetime.

 

[Gibsons]

From the abstract linked above.

HJ Levine, J Am Coll Cardiol. 1997 Oct;30(4):1104-6

Plots of the calculated number of heart beats/lifetime among mammals against life expectancy and body weight (allometric scale of 0.5 x 10(6)) are, within an order of magnitude, remarkably constant and average 7.3 +/- 5.6 x 10(8) heart beats/lifetime.

 

[Looney]

Originally posted by: sundevb

Originally posted by: Hardcore
Here's an interesting tidbit.. did you know all creatures on this planet, live approximately the same number of heartbeats? Which is 1 billion. So a rat may only live a year, it's heart beats much faster, and in the end, about the same number as us.

The 1 billion heartbeats thing isn't even true for humans. Take someone with an average heartrate of say 75 bpm. That's 4,500 beats per hour, 108,000 per day, and 39.4 million per year. Average lifepsan of 80 years makes that 3.1 billion heartbeats, not 1 billion.

And each animal living the same number of heartbeats isn't true either. For example, whales have a very slow heartbeat, but they don't live for long periods of time. Take the Blue Whale. It only does about 8 beats/minute, which is roughly 9 times slower than humans. But they don't live 9 times longer than humans -- their lifespan is only 80 years (same lifespan as humans). That means Blue Whales only do about 8*60*24*365*80 = 336 million beats in their lifetime.

I'm not sure where you got this, but:

In fact, many other measures of lifetime activity are constant, regardless of body mass: in their lifetime, assuming they don't die young, all mammals have, on average, the same number of heartbeats, per unit mass they metabolize the same amount of glucose, and synthesize the same amount of protein, and they pump the same volume of blood.

Theories on Aging

Most animals live to have roughly the same number of heartbeats. In small animals, the heartbeats are much faster than large ones, but large animals live longer. So, generally, most animals live to the same age, only at different paces. Therefore, natural selection must weed out the genes that could cause damage to the body before reproduction in every single species. So, every species gets a chance to reproduce successfully and to look after the young before they die.

FlySci

The notion that all animals die at the same age seems ridiculous if we measure age in years and months, but it becomes rather logical if we count the number of heartbeats. Professor Vasilios Valaoras claims that most mammals living free in nature, that is, not in zoos or homes, have accumulated about one billion heartbeats on the average when they die. It is only the rate of the heartbeats that differ from animal to animal. Small ones, lile mice, live about three years, but their heartbeats is very fast. Middle-sized ones, rabbits, dogs, sheep, etc., have a slower heartbeat and live between 12 and 20 years. Elephants live more than 50 years but have slower heartbeat. Even before Valaoras, Isaac Asimov, had remarked "Whatever the size, . . . the mammalian heart seems to be good for a billion beats and no more."

http://www.saigon.com/~tuan/STAT8.HTM

Comparison of species lifespan provides convincing evidence that longevity is genetically influenced. An elephant lives about 10-20 times longer than a mouse, yet both animals have roughly the same number of lifetime heartbeats -- the elephant at 30 per minute and the mouse at 300 per minute.

Mechanisms of Aging

Need i get more?

 

[Kalessian]

I have 2 minutes, but I think sundevb has a point:

Whale heart rate:

"In general, the larger the animal, the slower the heart beat. The sperm
whale is the largest of the toothed whales. Adult males measure up to 18m
(60 feet) in length. The usual heart rate of large whales is from 10 to 30
beats per minute. The heart rate of any of these creatures has never been
monitored adequately to give species-specific information, given the
logistical difficulties involved. However, the heart rate of a smaller whale
species, the beluga, was measured once to be 12-20 beats per minute. Using
this information, one could deduce the heartbeat of a sperm whale might be
slightly lower than a beluga."

Whale Life Expectancy:

"We dont know for sure, but we know that the closely related fin whale
can live to over 80 years and I suspect that blue whales are very
similar. Unfortunately, most blue whales were killed by whalers in the
last century (369,000 in the Southern Hemisphere alone, leaving perhaps
a thousand or so today down there), so very few whales were able to live
out their natural lifespan. "

Info from the askarchive.

 

[dainthomas]

If one is so inclined, Tolkien delves quite deeply into this topic in the Simarillion. In particular, the history of Numenor is quite interesting as their downfall was enirely precipited by their desire for immortality (specifically, their jealousy of the elves). The Valar tried (futilely as it turns out) to explain that Man's death isn't really a death, but a release from the cares and sorrows of this world. And in fact that it is the elves who should be jealous since it is they who are confined to this world until it comes to an end.

 

[r00tcause]

Originally posted by: her34
why do bodies age until death, instead of aging until adulthood and maintaining that state.

is death evolutionary necessary?

Pick up the latest Popular Science (Jan 05) and it will give you the answers you seek.

 

[InseName]

kinda funny cause whats keeping us alive is also killing us such as gravity and O2, muons and other waves also kill us

 

[JAGedlion]

Just saw this earlier, not sure if it was disputed, but I skimmed through and didn't see it, telomerase adds telomeres to the end of cell's DNA. Because some is lost in every replication, so without replacement, eventually you run out of telomere's (basically unimportant DNA stuck on the end like the plastic things on shoe laces) and you start losing important stuff.

Telomerase was infact invented in a search for a fountain of youth, but, fact is, right now we have no idea how to stop aging. Telomere's are just a very small part of the human condition. After all, merely immortalizing a cell line often completely changes its ability to carry out its original functions. In reality, you have to think that if people didn't die how slow any form of evolution would be, especially when you look at how slow it already becomes considering our ability to take care of ourselves. In the end, why not, wouldn't it be great to live in a posthuman world? At the same time, if I had to describe and ideal world, it always seems to sound strikingly similar to "Brave New World" and yet it all seems so wrong in that book. I think its really much more of an ethical/philosophical question.

 

[NewBlackDak]

Anyone have any nagging injuries?
If we stopped at our peak then alot more would be very active. After a couple hundred years every major joint in your body would've sustained some kind of damage. Ouch is all I say to that.

 

[Cattlegod]

Because if we lived forever, then we would have never existed.

 

[Cattlegod]

Originally posted by: NewBlackDak
Anyone have any nagging injuries?
If we stopped at our peak then alot more would be very active. After a couple hundred years every major joint in your body would've sustained some kind of damage. Ouch is all I say to that.

I did the math once, and I think that just by death from accidents you are only capable of living for 5000 or so years before you get into a car/plane crash/murdered/poisoned/drown/burn to death in a fire/some other horrible death.

 

[FreemanHL2]

I HATE STATISITCS, likelyhood only produces doubt, i'd rather not know thanks. Anyway i did here somewere (vaguly) that oxygen is actually bad for cells, but they are coated in a protective layer (don't ask) and after time the protective layer wears down and becomes less efficent, then our cells start dying.

I see no reason why we cannot live forever, all you really need is a flawless replication process. Obviously ppl doubt weather such a "perfect" processs is possible, i think the key is error correction, if it makes a mistake it learns, it adapts. I don't see a reason why our bodies can't evolve on the cellular level, adapting and changing throughout our lives so that we can continue to replicate cells forever.

Personally i am a religious person, but if it were possible for man to manipulate their DNA and live forever, i'd say we'd have to continue to modify it as errors occur. After all i don't think anyone here belives mankind is capable of creating a PERFECT DNA strand without error.