Discussion of all aspects of cellular structure, physiology and communication.
there is no sense of us dieing evolution-wise. if we live forever our genes would spread even better. in school i learnt that inside the cell there is a molecule which getting shorter every time the cell divide and that is why at the end there is death (no more renewal of the body). but evolution can cancel this. my suggestion is that if we live forever, there will be stagnation in the variety of species, hence, vulnerability to others. פגיע
what do you say?
No as you say there is no sense for death evolution wise. However life is also in the hands of entropy, and there is a time where it become impossible to repare the accumulated damages, hence death.
The molecule you are speaking with is called telomere and actually represent the ends of the chromosome in the cell.
But remember that evolution acts on individula, not on the species. If you had genes that could allow to profit of your own species at its cost, but to the benefit of your offspring, they would probably spread. But you could that this is not necessarily a winning strategy in the long term. You can read on game theory and genetics to learn more on the subject. I think there is at least one chapter on the subject in Dawkins' Selfish gene.
Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)
i can't think of what could be those accumulated damages if all our body regenerate it self, exept the brain which is not regenerate but still able to make new cells) and maybe other neurons which are inside the body and not really exposed to external effects. even if we'll focus on individuals, wht should'nt evolution try to make me live much longer?
I think this is a matter of debate, but it is also possible that those infamous telomeres are there to protect you from your own cells - that is, they prevent cells to uncontrollably divide and become cancerous in case they lose some other control growth mechanisms. After all, when there is cancer, also the telomere shortening ceases. So how about if you think it this way: that the telomeres are there for your own good?
This being said, the nature does have means to make organisms live much longer. Whilst over 99% animal species have shorter life span than humans, there are some animals that easily surpass us. For example, I read that they recently discovered that some deep sea clams may live up to 300 or 400 years of age. And of course, there are plants such as many trees that can live hundreds of years, some possibly over a thousand years.
So even though it is clear that nature can create long-living organisms, the vast majority live just a couple of months, or couple of years if they are lucky. In my opinion, this suggests that there is a strong evolutionary reason behind death of old age. Thus it seems that you or I not living forever is good for our species, even if we did not like it. The nature _could_ have made us live longer, but it just didn't!
What Canalon said about entropy and accumulating damage: it certainly plays a role in our aging, but what I do not know if that is just a symptom of our repair mechanisms being "deliberately" made inefficient by evolution, or is that something inevitable that even evoltuion cannot fix. After all, all those very long lived organisms that I know of are either reptiles or other cold-blooded animals, or plants, which all have low metabolic rates and thus probably less oxidative damage and defects resulting from that. Size has similar effect: small animals have fast metabolism and usually also die earlier.
Then again, it has been reported that some species of birds (which have fast metabolism as warm-blooded animals) have developed a means to slow down aging and they live much longer than other animals of their size, and they apparently can lenghten their telomeres. Leach's storm-petrel is one of these species.
as far as i understand the topic, aging (and then death as a consequence) is a programmed event, composed of complex regulatory pathways. That's why you can administer small molecule inhibitors such as rosveratrol and rapamycin which lengthen life-span and retard aging. This is still a very active field, but i think we can tell for sure it's not just wearing out of the machinery.
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter
There are a bunch supporting theories both the macro at a population level amd the micro from physiology to basic cell/genes. I'll go over the cell level one. The reason cells are programmed to stop growing is to prevent things like cancer. In each cell there are more genes that prevent cell growth than one that promote it. The extra growth inhibiting genes are there as a back up system in case some mutation does happen. So like in many first year biology books in their one chapter on cancer often mentions that it takes multiple mutations( one is never enough) to cause cancer.
As far as the other arguments, they are pretty easy to figure out
Just wanted to add, that evolution cares only for procreating. After procreating is done, the body is no longer needed.
Growing old seems to be a main focus of the baby boomer's generation. How to keep living for an extended amount of time after the body is done procreating, in order to live for only ourselves and not for nature. Thus how do we manipulate the genetic code that may have us programmed for death after the hormones have given out? And for the breakdown in all the mutations we accumulate during our lifetime (which even breathing the air can cause all sorts of mutations in our body, and also to mention the UV rays from the sun that cause havoc on our DNA) is the end resulting in death also.
Try not to think of living longer, but living more in the time you may have after the procreating period has passed.
hello and thank you. still you haven't explain why the body must die? it is a different question than how to handle cancer
I can not figure it out, so if you can mention it i'll be glad
how do you know the evolution doesn't care ONLY about genes?
and because i am the the carrier of MY SPECIFIC genes, they should protect ME better
Did you know that the average person faces about 100,000 mutations a day, and that the body is able to handle all those repairs of those mutations? But that 1 might be a mutation that slips by the repair system and causes the disease for the organism? And in today's culture, that mutation rate can be increase by all the added environmental factors that attack the body's systems making the number 100,000 seem minimal.
The body is a biochemical machine and needs to be taken care of. We need to be educated on how to do this.
Epigenetics. You can have the DNA/genes, but if it isn't expressed then you don't really have the gene. Which is great if you have a mutated gene that causes a malfunction in the organism's system, then that is great for the organism (though it will be in the germ line probably and passed on, and inevitably expressed in some one).
Evolution doesn't work with just one individual . . . usually. There are major mutations that are dominate and become established in the genome forever onward. But most of the time it takes more lifetimes than we would care to think about in our own lifetime. And yes, your genes should protect you, but do you protect your genes? Sunlight, bleach, pesticides, contaminated water, hormone induced meat, polluted air/smog, preservatives causing hormone imbalances, etc., (trying to name just a few of the popular biochemicals that mess up the DNA or even the epigenetic patterns) are some of the things we need to watch out in order to protect our DNA.
The easiest way to tell is your skin. How is your skin? It is the first that is usually attacked by DNA damaging factors. And your intestines/GI tract is the other one. Both systems are exposed to the environment first.
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