Why has Evolution limited the human lifespan to approx. +/- 75 years?

I have read in passing -- I haven't read any actual scientific paper on it though -- that our relative longevity may be a side effect of our protracted juvenile stage. Primate children spend longer in a mentally plastic state, being cared for and being instructed, than most other species.

It is our great strength as a species; that we are plastic and non-specialists. And our trade-off is helpless babies with huge heads that require families or even social groups to protect, support, and educate.

No, our lifespan is around 100 years. It's all about our intake.

To come back and answer the question in the OP, we have various genes called p53 and p63 (probably a few more) that alter cell regulation and death. If you were to deactivate your p63 gene, you would age about 25% faster.

The p53 is involved in the cell regulation cycle as well. However, when it mutates, you have increased and unregulated cell regeneration, usually in the form of cancer. Between 50-80% of cancer is attributed to a mutated p53 gene in some form or fashion.

These types of genes are called caretaker genes that help regulate your actual chromosomes in the cell. At the end of each chromosome you have something called a telomere. Think of a telomere as a fuse on the end of a stick of dynamite. You can't increase the fuse length, but you can cut it. The fuses don't contain any explosive material, thus you won't hurt the dynamite when you snip the fuse a bit. However, if you snip the fuse too much, then you start snipping the actual dynamite, making the stick of dynamite not work as intended.

These caretaker genes help your chromosomes by preserving your telomeres. If cells divided without telomeres, they would lose the ends of their chromosomes, and the necessary information they contain. The telomeres are disposable buffers blocking the ends of the chromosomes, are consumed during cell division, and are replenished by an enzyme, telomerase reverse transcriptase.

However, once a cell reaches the end of its telomere, it either shuts down or goes into a stasis (senescence). Aging is the result of the majority of your cells going into stasis. Organs deteriorate as more and more of their cells die off or enter cellular senescence. Telomeres vary in length by species, which may answer the poster's question who quoted me earlier.

tl;dr Your DNA is a stick of dynamite with a set fuse. When the fuse runs out you go boom.

Doesn't matter. Modern welfare state euthanasia limits your lifespan to approx. +/- 75 too.

Nature in it's infinite wisdom has determined that we're relatively useless after our period of procreation. By useless I mean to the state of the planet, not society. If anything, we're detrimental to the state of the planet as a society. This gives the next generation a whack at doing it's worst to the environment without causing total collapse of it's environment. If anything, life spans should get shorter to form a balance.

All evolution cares about is that your offspring survive. Once you've seen your children to adulthood, and they no longer need taking care of, then so far as evolution is concerned you're of little or no further use. What's surprising isn't that people only live to 75 or 80 but that they live even that long considering someone that age is more likely to be a burden on their offspring than a help.

Maybe, if they're all standing shoulder-to-shoulder. But that doesn't address how you feed them or provide them with water and energy. It's been calculated that it would take five or six planet Earths to support the population of the entire world on an American lifestyle.

The Bible says it well:
Psalm 90:10
King James Version (KJV)

"The days of our years are threescore years and ten; and if by reason of strength they be fourscore years, yet is their strength labour and sorrow; for it is soon cut off, and we fly away."

Because evolution is a fairy tale, and God Himself limited lifespans to 70 to 80 years on average, see Psalm 90:10

More propaganda....

We were not meant to die, but we corrupted God's plan, so the consequences of that is death.
Fortunately, he sent his son to redeem us of our corrption, so through him, we can have eternal life.

Yes, indeed, time kills...

When man doesn't know, he gives the 'it came from nothing' answer.
Nothing plus nothing equals nothing...I can't be persuaded otherwise.

Science contradicts itself by saying that everything has a cause..

It use to be 1000 years, but has been steadily reduced because of man's addiction to doing things man's way instead of they way man was designed to live. Hope this helps. Evolution cannot explain anything because it simply is not true. Do the fittest survive? Yes. Do animals evolve from one thing to another? No.

I always found it fascinating the life spans in the bible. In the bible they were shown living up to 900 years and as you read the bible you notice it gradually go down dramatically.

"Science contradicts itself by saying that everything has a cause.."

Since when can evolution care? Evolution has no brain it could not develop any thoughts about offspring.
Why would evolution know that people after 80 are useless? Evolution doesn't even know that people exist.

Sorry to tell you that you have not understood evolution.
Evolution is a brainless survival of the fittest.
In our case we should have people of all different age groups with limited lifespans say from 20 years up to 1000 years and the "lifespan group" which is the fittest would survive.

But of course we know that such an epic battle never occurred. Sorry, but I feel you id not answer my question.

I don't think that's true I believe in God.

But there is a science law that stated energy cannot be created nor destroyed only transferred.

The 1st law of thermo IIRC

So, suddenly evolution or nature how you call it has developed a brain and even became wise?

Has science not established that evolution is a thoughtless process? How can evolution (or nature as you call it) develop any thought process?

Coul you please explain where and how these thoughts are generated by nature? Is there a group of wisemen called Nature, or where could we find nature's thinking faculties?

You describe a biological process how our lifespan could be regulated. But you did not give any information why our lifespan is more or less cut off at a statistical age of 75.

I was not interested in how this limiter works, I was interested who or what, in his infinite wisdom (as another poster claimed), cut our lifespan at around above mentioned age. The why we only live to that age is of interest to me, not how it is accomplished.

Maybe you could try again?

Last Edited by Tekunda on 03/06/2012 10:56 AM

The short answer is entropy. The long answer is trial and error of human nature.

Our bodies initially have the ability to copy and possibly regenerate telomeres at birth, because of a high level of telemerase present in each cell. However, over time that level decays and aging occurs. This is why a child who has a scar will heal in a short time, and why an older person with a scar will develop a large bruise. The cells only have a limited amount of regeneration cycles left, and many are dying for good.

Now, I'm still aware I haven't answered your question as I was aware I didn't answer it in my first post. I just take a long time to make my points.

A poster above said that people in the Bible often lived 900 years. For the sake of an argument lets assume this is true. Let's also assume that their large lifespan was dictated by a long telomere length and a friendly environment to humans (less radiation and cancers) as it is today.

If this had been true, then something must have happened to shorten those telomeres in all future humans. Maybe the atmosphere partially deteriorated, causing mutations in telomere length. Maybe a nuclear war broke out, causing a shortening mutation in telomere length. Whatever the cause of the shortening (a type of entropy), the effect is that we have the lifespan we have today. Now, I'm aware that is a big assumption, but I did so to try and see something from a different point of view.

That point of view is that our telomere length is not the result of a building up to a maximum of 80 years, but the result of a balancing act of human society.

Say we find a way to increase our telemorase without causing cancer, thus creating a type of sentient immortality (Cancer cells are immortal if nourished). Chances are that some point in that future history, our telomeres will be shortened once again by humans or nature, shortening our lifespan. Judging from our past human history, we are a violent and selfish species. When nation has a new toy such as nuclear warheads (or immortality), another nation will kill everyone just to prevent others from having it. If you don't believe me, just take a look at the news with Iran.

Therefore, the long answer is our ~80 years of lifespan is a result of human nature of violence and conflict with evolution/adaptation being the method used to reach that lifespan. If our species had never warred and always been helpful to all other humans, we would have reached a technological point to increase our telomeres a long time ago. Even if increased solar radiation reduced our telomeres, a helpful and caring society would have an increased lifespan for multiple reasons. The nature of conflict between humans dictates our lifespan as a species.

Last Edited by Zedakah on 03/06/2012 11:34 AM

it's not even that, it's all the poisons you've been innundated with in this generation

I think I can follow what you say. But there is still a problem. First of all, we have no clue, if we ever had telomeres allowing us to live 900 years, so all of what you say is pure speculation.

But the unsolved issue is how evolution establishes a lifespan. Even if 900 years were true, how did evolution arrive at 900 years. Why did it allot 500 years?

I am still missing the answer (I by now understand the mechanism)who decides how long the telomeres of each species are. The lifespan problem is not only valid for humans, it applies to every species which ever existed on this planet.

Why does a horse life 30 years and not 60, why do bees live only a couple of days and not one year? Something, (since we cannot say someone when dealing with evolution) must have decided on allotting a specific lifespan to a specific lifeform. What decided how long each lifeform is allowed to live on this planet.
Why are my beautiful cats allowed to live so many less years on this planet than a crocodile? It wouldn't have killed the planet would cats live up to 25 years.

I think after reading the responses that nobody has the slightest clue why all life on earth has a specific lifespan.
And what I noticed is that many treat evolution like evolution has its own intelligence and can make intelligent decisions.Like one wrote, nature in her infinite wisdom....
not realizing that blind and dumb nature has no intelligence but relies on dumb chances of mutation resulting in a so called survival of the fittest.

These people do not realize that they instinctively point to a Creator who is regulating his Creation. That is why they come up with statements about nature having some sort of intelligence. They could easily replace evolution and nature with Creator, but then they would have to admit that evolution cannot determine how long a species is allowed to enjoy life on this planet and that there is more to life on this planet than dumb, stupid, unregulated battles of the survival of the fittest.

Because almost everyone does the same stupid mistakes and can't take care of their bodies as they should and old body dies at that age, there is plenty of people live well above 100.

I cannot edit (seem not logged in) so above post must read:

Why did it NOT allot 500 years. (Otherwise the sentence makes no sense)

And why can't we live at least to 175? I wouldn't mind that at all. Any idea why evolution was such a miser in giving us years to enjoy?

In order for a species to have a chance to be diversified, older versions of that species have to die off eventually. It's certainly useful for an individual, from its own point of view, to live as long as possible. But if these few old individuals were to live forever they would keep pumping out offspring that were only one generation genetically diverse from themselves. That's not much variation and variation is the key to survivability of a species over a long period of time.

Overtime, with multiple generations you get a lot more variety in a species, and thus a lot more mutations. Most of those mutations will be inconsequential, useless, and perhaps in a few instances even detrimental to the survival of the offspring but occasionally a mutation is beneficial to survival. With the eventual death of older members of a species, their specific genetic code is cycled out of the population so you can get a more constant mixing within the gene pool. The fact that they were strong enough to survive and procreate means they've been a part of adding to this gene pool, so many of their traits will continue, but by dying off eventually it allows the species to become ever more diverse.

It's really a big numbers game. More genetic diversity in a species means more opportunities for there to be new traits that help keep the species as a whole alive. With a few individuals contributing too much to the gene pool, overtime it starts to lack diversity and thus a single event, one really bad disease, a sudden massive change in environment, etc. can more easily lead to the death of the entire species. By evolving so that individuals die off after enough time to contribute to the species gene pool only a few times, it actually promotes genetic diversity which is good for the whole group.

Last Edited by LifeInDeath on 03/06/2012 02:38 PM

I know I based the argument on speculation, and I even made a mention of why I did that.

Telomeres are one factor that determine your age. The other factor is your metabolism. If telomeres are an engine in a car, then your metabolism is the gasoline. The more gasoline in the engine, the faster you will go, but the shorter your travel time will be. The faster your metabolism, the more your cells divide and the shorter your overall lifespan is.

What most people fail to take into account though is that a faster metabolism also provides a faster processing speed of your brain. This goes back to the first post I made in this thread, that a cricket perceives time much faster than we do. If you were the size of a cricket with the same metabolism, one day on earth might feel like an entire month to you. Thus the lifespan of a cricket might actually be perceived as the exact same as the lifespan of a human (from a cricket's perspective).

This is similar to Einstein's relativism. Where he put people in a ship and sped the ship up to near light speed for his example, I am just getting rid of the ship and speeding up your natural bodily processes. The result is that you would perceive things no different than you do now, except the entire world would move much much slower. Why do you think it's so hard to kill a gnat with your bare hands? To them, your hand is moving in super slow motion and they can dodge it easily. That's why flyswatters work well, because they greatly speed up the swatting motion by reducing air resistance before a change of air pressure can be detected by the fly/gnat.

My point is that your cats' lives through their eyes might be just as long as your life perceived through your eyes.




I've noticed this as well, and it is a product of lack of understanding and personal associations. It is the exact same mentality as flipping a coin and associating a "heads" with good and "tails" with bad. They are only good and bad because people associate them as good and bad due to preferring one over the other.

How does that relate to evolution?
Because we associate life with good and death with bad. This may be justified to some extent, but the fact that we have only ignorance of death means that it is not a justified conclusion.

For example, say a nuclear war broke out and caused our western society to retreat back to the stone age. Adaptation and survival of the fittest would weed out the "weaker" people. The fallacy I see with many supporters of evolution is that the remaining people are perceived as "better" in some regards, because we perceive life as better than death.

Yet, if you took a survey of people and asked them if they would rather live in the aftermath of a nuclear stone age without modern conveniences and American Idol, or die in a nuclear blast within an instant; a large majority of those people would prefer to die. Thus, death is perceived as better than harsh environmental surviving. Thus, it is the descendants of survivors of adaptation that bias our opinions, giving us associations of "good" and "bad" with something that is impartial to life or death, since we are largely ignorant of what death is.

In this regard evolution rarely advances a species for the betterment of the species. It merely prolongs the inevitable demise of a species (or life in general) through adaptation/speciation. We fail to take into the comparison the quality of life within a species, and instead just compare life vs. death.

Sickle cell anemia is a human adaptation to fight malaria; however, it is below the overall human condition compared with a human with full blood cells and a natural immunity to malaria.

Sure, there can be good mutations, but there are not only good mutations. Most are bad mutations that a species learns to adapt, that we later perceive as good because we perceive life in general as good, instead of comparing the quality of life within a species.



I'm going to post another post after this one that finally answers your question, I just want to submit this post before glp resets.

Last Edited by Zedakah on 03/06/2012 02:43 PM

The only answer "evolution" can provide to your question is a matter of population control and resource management. The perceived goal of global evolution and adaptation is the balance of resources and sustainability between all species for the maximum amount of time. Again, this is with the human preconception that life is good and death is bad, and that life is moving forward (that's why I put evolution in quotes above, because it doesn't care if life moves forward).

When the population of deer becomes larger than a normal year, the following years the local predator population will increase as well. More resources to sustain predators = more predators.

After a while, the deer population thins, and so does the predator population after some time. This cycle continues until there is a balance of population. This balance only lasts until there is a new species introduced or some new environmental change/disaster.

The same works with humans. We live in a location and society as long as our resources let us live there. This also is applicable at the level of our cells and DNA as well as a global universal level of all life on this planet. Our cells only survive with the appropriate amount of resources, just as all life fights over the resources at hand. It is an ongoing balancing act until someone emerges on top for a short while.

We are just now starting to look at this balancing act in the present as a point in a timeline, but we have yet to look at this overall balancing act from the timeline as a whole. Our ages are the result of this balancing act. All actions have equal and opposite reactions, including human actions. When one human takes the majority of resources, the rest of the humans attack that one human. Of course in our day and age, our resources are being stolen and we are just being continually lied to about who stole them. But that doesn't change the fact that we still have wars over resources.

Our lifespan is a reaction of previous actions taken, whether those actions were by humans, nature or some astronomical event.

If our atmosphere slightly deteriorates, the reaction might be a shorter lifespan. If Earth had twice the atmospheric pressure that we do now or a much stronger magnetosphere to block more harmful radiations, the reaction might be that we live much longer. There are an infinite amount of other possibilities that would reduce or lengthen our lifespan by either depriving our cells of resources or prematurely damaging our DNA. What we have today is a result of those actual possibilities (that we are largely unaware of) that have limited our DNA resources and regeneration ability to ~ 80 years. The DNA we have today that is adapted to live in the environment we live in, which is determined by both nature or species interactions.



So to answer, 'Why has "evolution" limited the human lifespan to approx. +/- 75 years?'

Because that's the approximate amount of time your body can survive in your environment. That's really no different of a question of "Why can I breath underwater for only 1 minute?" You have limited resources in your body that deplete over time. In previous times, we may have had more resources in our DNA, or a planet that protected our DNA better. However, currently our life spans are a reaction to the our limited resources and harsh environment.

If you want to live longer, then either change your environment to be more accommodating to human DNA, or work together as a species to alter your genetic resources so they don't deplete as fast (telomeres and telemorase). But I don't see that happening as

Last Edited by Zedakah on 03/06/2012 03:23 PM

Worms may have the answer within their biology.

Source: [link to www.sciencedaily.com]

Other way around. You lost yours and became stupid.




It's a manner of speech. We say the truck pulled into the loading dock at 12:12. No-one is suggesting it drove itself. We say that two masses will feel a mutual gravitational attraction. It doesn't mean we are implying they have feelings, much less romantic ones.

Human language. Learn to use it.




And now you are just parroting the OP's "Where is the brain?" refrain. Its an emergent quality. It doesn't require attention, any more than the formation of a snowflake or a star.