Why do we get old?

Your genes have a switch that tells your cells to stop multiplying at optimum rates

or Try here and here

I think without death, life loses meaning.

@btko. eternal life rocks because of death, its always over our heads, and I think this is why people have any desire to be moral, fear of the unknown and/or god(s)

@scrumpulator: I know how it happens. I’m wondering why.

It is hard to remove it from the biology. We are corporeal beings and our bodies wear out.

Right now, I would not want to live forever.

@niki: I always figure it’s because we can’t evolve as a species if we never die.

We age because it is required for the cyclical effect. With every birth their is a need for education of the basic and advanced ideas of life. The parents are charged with the basics at first, they care and support the family unit. As this unit grows and the children come of age, the parents are older and more wise, this is when the wisdom that is required learning of the children enter the phase where they are to start a family, The most wisdom I have gathered has been from the older generations who have seen it all, I am doing this right now, and I am at the age where I see my parents skin starting to wrinkle and their wisdom multiply. We also age so that the people around us can appreciate the lives that we have lived. We honer accomplishments and additions to the human race.

Because other wise there would be no space for new people. The world is overcrowded as it is imagine how bad it would be if no one ever died.

But I didn’t ask why we die. I asked why we get old. Our bodies could just as easily program death at some point (age 100? 1000? whatever) without getting old first. Couldn’t they?

@nikipedia ”@scrumpulator: I know how it happens. I’m wondering why”- that’s the best I can do as to why. It is necessary for learning.

@niki: Out of curiosity, would you want that? Do you think there’s a point we should hit when we stop getting older physically and then just wait for the “clock to run out”?

I know convention is to say that we don’t want to live forever, for various reasons—because, as btko said, without death life has no meaning, because we’d get bored or overwhelmed or whatever. But, truthfully, I really would want to live indefinitely. I really enjoy living, and I can’t imagine ever getting bored with life—there are so many things in existence to enjoy!—and besides, things are constantly changing. I certainly haven’t perfected the art of living yet, and forever seems like a good amount of time to work on it.

As far as aging goes, I would love to stay young for a long time—certainly longer than I am going to stay young. I like having this body and being able to abuse it in various adventurous ways that I’m sure won’t be accessible to me some day. But someday I’d also like to experience what it’s like to be old. Hard to say when that point would come.

For me, both of these things are a matter of not having enough time to experience things fully before life drags me on to the next bit. I’d just like more time to figure out how things work in this bit and enjoy them before moving on.

I don’t really believe there is any “why” to death or aging. It’s just a fact. As marina said, it’s hard to remove it from the biology. It’s like asking why the sun rises in the morning or why gravity exists. They don’t need a “why”—they have a “how” and that’s just the way things are.

@niki why do you think there has to be a reason? Aging is just a side effect of the biological process. Evolution only had to make sure you could live till 30 (ie mature procreate and ensure your children procreate). As there has been to evolutionary pressure past that age biology is left to get on by itself. There is no reason why we age and there doesnt have to be one, thats just how it is. Sorry.

I disagree, lightlyseared.
There absolutely must be a reason, the way I see it.
Most other animals, as you said, are born, procreate, assure their offspring procreate, and then die. Something is different in humans. Why do we stick around into our 70s, 80s, and 90s, contributing nothing to the species from a biological standpoint? There’s something different going on here. I don’t know what it is, and I’d be very interested if anybody else had a take on this.

@ lefteh because we contribute in other ways. There is more to life for a human than just spawning brats to replace your self. There are arts, philosophy, literature, politics and all the other things that differentiate humans from other species. Biologically speaking however once you’ve had kids thats it.

@lightlyseared: Because not all organisms undergo senescence, and our cells don’t (exactly) undergo senescence. So it looks to me like it’s a trait that we evolved, and I’m wondering why that would have happened.

And I think @lefteh was referring to our value from a biological standpoint, since in general death doesn’t seem to give us “get out of jail free!” cards for arts, philosophy, etc. Only for biological mechanisms that help us survive.

Niki’s got my meaning right.

@lefteh OK, sorry, from a biological standpoint what allows us to survive is the general lack of stress in our lives (for example I doubt you have to worry where your next meal is coming from, where you will sleep tonight etc). If you look at life spans in areas of the world with civil war and ethnic cleansing etc life spans are much shorter (getting close to 30 sadly and thats not including the people who are murdered.

State of the art medical care also helps.

(@niki I like to think of myself as slightly more complicated than a single celled organism. Also your wiki link does suggest a reason why we might of evolved not being immortal)

Death is about evolution. Both biologically and culturally. It brings new ideas, and encourages us to use the time we have wisely.

What do ideas and innovation matter if you can’t go out with a bang? Your thoughts and contributions are slowly forgotten as they are replaced by the new?

I would not like to live forever. Well, I would be interested to see where we are in 1,000 years… but for the sake of it? I think I’d be horribly depressed.

From the standpoint of natural selection, there isn’t much of a downside to aging, is there? Once we’re out of the reproductive loop and have assisted in the raising of our children’s children, then we’ve pretty much done our bit for our species. Natural selection will only select against traits that work against reproductive success (as far as I understand it), and I’m not sure aging does, at least historically.

The factors that limit our reproductive life aren’t linked to senescence (again, as I understand it). Sperm quality in men declines as a result of accumulated genetic errors, and women are born with all of the eggs they will ever have. Pushing reproduction past a certain age entails a downside for the species that’s unrelated to aging, so one would expect that natural selection would limit our childbearing ages.

Aging sucks, but the processes that shaped our biology aren’t guided by how we feel about the result.

Now I’ll just sit back and wait for the people who actually know what they’re talking about to correct my misconceptions.

My time today is limited, but I will say that you cannot separate the how from the why. Senescence is a consequence of normal cellular functions, and so it is relatively predictable what will happen over time. As for the why, again, I go back to the fact that all cellular (and mechanical) functions break down over time. The biggest reason why (and how) is that cells accumulate mutations in their genes and the ends of our chromosomes (the telomeres) get shorter and shorter.

To answer Lefteh’s point, humans weren’t really designed to live as long as we do. It is an accident of modern medicine that we live to 70 and beyond, owing to better hygiene, vaccines, and antibiotics. If not for that, we would all die (relatively) young.

I would love to live forever. Assuming I was the only one who could live forever, that would be depressing, but I could still handle that. It isn’t like I’m incapable of socializing. Imagine the knowledge you would gain, and all the experiences you would live through. I could live long enough to see other planets colonized, leaps in technology, and so much more. It would be amazing to see all of what is to come. It’s a shame we all have to die one day…we are stuck using our imaginations =)

I believe one argument is that at some point we contribute more effectively to the success of our genetic material (i.e. offspring) by not having more children and spending all our energy instead raising the ones we already have, as well as their children (a grandparent argument). In other words, there is a balance between reproductive quantity and quality, especially in highly socially complex animals like humans. Once reproductive capacity has ceased (in women, at least), there is no longer any evolutionary pressure selecting for the kinds of traits that attract mates: beauty, athletic prowess, arrow-shooting precision, whatever; in other words, youthfulness. If evolution, thus, does not favor the maintenance of complex “anti-aging” proteins like DNA repair enzymes and telomerase beyond reproductive age, they will presumably start to decline in number or quality because maintaining them is highly energetically unfavorable.

@niki…just as I have come to expect from you: a great question with vastly expanding detail and absolutely delicious selected topics (particularly the “lattes”). Thank you!

@shilolo- Thanks for a concise, scientific answer.

Stress can hurry up the process. I can personally vouch for that. I’ve aged so much in the last year it’s hard to believe. 2009 was a bitch of a year. It shows and I’m not happy about it one bit.

Think of it as a tremendously long string of days when you ‘got lucky’. Just not the way you had in mind, maybe.