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Why do we die of old age?
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Xarog
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I don't recall the specifics, but yes, it's genetically programmed.
Scientists were recently able to GE some simply organisms without this aspect written into their genetic code. They're still waiting for the things to grow old, iirc.
I think it has something to do with RNA, and the way that cells add to RNA every time they replicate.
With regards to an evolutionary aspect, dying of old age is a bonus. The longer you live, the longer you compete with your own children. And without a species being forced to make copies of itself on a regular basis, evolving would be a much lengthier process.
Scientists were recently able to GE some simply organisms without this aspect written into their genetic code. They're still waiting for the things to grow old, iirc.
I think it has something to do with RNA, and the way that cells add to RNA every time they replicate.
With regards to an evolutionary aspect, dying of old age is a bonus. The longer you live, the longer you compete with your own children. And without a species being forced to make copies of itself on a regular basis, evolving would be a much lengthier process.
bdt
Executive Member
Some light reading on the subject but Xarog puts it simpler. 
Surely the genes which instill an urge to reproduce are not the same ones which cause an organism to age?
From a logical point of view (i.e. for a thinking organism) it makes sense that impending death would spark an urge to reproduce, but I'm pretty sure an immortal bunny would produce offspring as rapidly as your standard mortal bunny
(this could be an interesting experiment for the future).Is there any specific reason why the rate of reproduction (and therefore also the rate of evolution) should be dependent on a mortal existence?
Xarog
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Because the Earth is finite. There's a certain number of resources available, and you can't exceed that limit. A 5 acre plot can only house so many rabbits before some of them have to start dying because the food runs out.Surely the genes which instill an urge to reproduce are not the same ones which cause an organism to age?
From a logical point of view (i.e. for a thinking organism) it makes sense that impending death would spark an urge to reproduce, but I'm pretty sure an immortal bunny would produce offspring as rapidly as your standard mortal bunny
Is there any specific reason why the rate of reproduction (and therefore also the rate of evolution) should be dependent on a mortal existence?
If a rabbit typically lives as much as 1 000 years, then unless there is something preying on the rabbits, a new generation of rabbits will only arrive every 1 000 years. If there is no aging, one of the older rabits has to die for a new rabbit to be able to survive on the same plot of land.
On the other hand, rabbits now live, what, 5 years maybe? That means that they are creating new generations 200 times faster than the 1 000 year lifespan rabbits. The 5 year rabbits will ultimately be the more successful species because as each new generation adds new changes to the genetic code, the chances that a given rabbit will survive a new evolutionary pressure increases. Over the space of billions of years, this pattern of 'turnover' would firmly establish in most living species that didn't become marginalised/extinct.
Lord Anubis
Expert Member
it's gonna hurt 
Praeses
Executive Member
Aging is defined as inceremental loss of the body's ability to adopt to changes in the internal and external environment. This loss seems to be genetically preprogrammed, and death is the final and penultimate example of this loss of the body's ability to adopt to changes in the internal and external environment. Each time a cell replicates small mistakes called mutations occur at the molecular level to nucleic acids like DNA and RNA. Over time they accumulate and result in the loss of ability.....Think of a photocopy of a photocopy of a photocopy of a photocopy.....In other words death is also preprogrammed into cells and is considered part of life, or natural.
Praeses
Executive Member
This generally happens at the telomeres. I believe some experiments have been done where they add a telomerase enzyme to some cells which prolonged cell life although I don't know the details. Try googling
Praeses
Executive Member
Erm, give an example of the animal that's most evolved? If you say human, you are quite wrong
Humans are more successful, but not more evolved than other organisms.
bekdik
Honorary Master
Most common reason is that you starve to death -forgetfulness stops you from remembering where the food is.
If forgetfulness doesn't do it, then inflation ensures you don't have enough pension to buy food.
Either way you're a goner
If forgetfulness doesn't do it, then inflation ensures you don't have enough pension to buy food.
Either way you're a goner
kronoSX
Honorary Master
who do you think programmed that gene in the human race,I always wondered.?
kronoSX
Honorary Master
will check thnaks
Moederloos
Honorary Master
Hmmm, his makes me think of something. Not sure if its the weak anthropic(?) principal or not, but let us give it a go:
We grow old and die, simply because if we did not, we would not be here to discuss the issue.
Consider: A early form of life does not grow old and die, therefore this life form is less likely to evolve. No evolution leads to less evolved life, leads to no "us" to ask the question.
There may well be planets with immortal life - but all that life is very basic, and cannot ask the question "why do we die?".
Just in case a Nobel prize is awarded for that, remember me!
If it is a stupid idea, forget me!
Praeses
Executive Member
Free radicals easily bind to cell structures/compounds causing them to be broken down by the cell. If too many proteins for instance are affected by free radicals, it may take a while to have them all broken down and they can continue doing their normal processes in a different way eg. cause mutations during DNA replication. If the cell contains too many mutated proteins due to free radicals, the cell will "commit suicide". This is what happens with smokers. Too many free radicals in lung cells -> cells die -> less lung capacity. Cells that do survive might've undergone some bad mutations -> cancer.
Consuming foods containing antioxidants reduce the levels of free radicals -> less mutations, less cell death, cells live longer -> person lives longer.
Erm, give an example of the animal that's most evolved? If you say human, you are quite wrong
Humans are more successful, but not more evolved than other organisms.
I'd like to disagree with that. I consider evolution to the the ability to adopt to the environment using anatomical or physiological adaptations in the body to achieve that. We humans, as far as I know, are the only species to develop such an advanced civilisations by virtue of our brain function. Electricity, complex social structures, advanced communication, advanced language, religion, formal education, formal housing....I could go on forever...All these are perculiar only to humans. Sure human brains are not the biggest on earth, but they are the smartest. The improvements of human brain function also evolved along with the anatomy of the body. Therefore the consequences of our intellectual evolution cannot be devorced from the physical evolution, which is what most people think of when hearig the word evolution.
Praeses
Executive Member
All those traits you mentioned are due to highly evolved cognitive functions. My point is, humans are equally evolved compared to...a lion. Lions have more brute strength, hunting instincts etc. than a human. Eagles can see further than humans. Humans are smarter than other animals. We've all come from the same ancestor(s) so all the animals have undergone evolution since time x. Some traits are just more useful than others but on a time-basis, all current organisms are modern and highly evolved, even Bacteria. They have complicated physiological systems too.
I think what you're thinking of could be better termed "adaptation", as that applies more to individuals adapting themselves to their environment, rather than a gene pool (a species) evolving to better survive.