by Kingcoal » Sat 05 Jul 2008, 21:47:25
There are trees that live for thousands of years, called bristle pine. Some trees are older than 5000 years. Nature made us to only live long enough to produce offspring and get them on their way. Our cells have a mechanism to limit their reproductive life. Some cells in our intestines can divide forever, probably because they are under high stress from all the bugs that we carry around in our gut. Anyway, for some reason, nature made the rest of our cells stop after a certain number of divisions. Why is that? Without that mechanism, we wouldn't grow old and develop health problems. We would still have health problems, but death from old age wouldn't be one of them. Cancer would probably become a problem, however because more cell division means a greater likelihood of mutation, but that's an acceptable trade off.
I think that us mammals evolved a limited lifespan because from our genes standpoint, once we reproduce and care for our offspring until they can go on their own, we are of little further use. Our genes are passed on to the next generation, so we become just one more useless mouth to feed. In other words, a limited lifespan is a species survival mechanism. Oldsters, being smart, devious and self serving, if allowed to live long lifespans, would dominate the younger generations to the point of hampering their ability to care for their children. Actually, in a way, that is the situation now. Seniors are rich compared to the younger generations and those seniors can think of nothing but demanding their social security from the younger, working population.
If people start living forever, then it will become necessary for the younger generations to kill old people to ensure the survival of the species. After all, the environment can only support so many people and those people need to be reproducing, allowing mutations to happen so that evolution can take place. In other words, our genes seem to prefer a new generation every 50 years or so and if people live a lot longer, that process would probably slow down to maybe every 100 years. Knowing that they are going to live a long time, people might start waiting too long to have kids while they "do" themselves. That's another thing that is happening now; some career women are finding that they put off a family too long.
With a short lifespan, you have to "get busy." If you snooze, you lose. Nature seems to like that arrangement. It allows necessary evolutionary changes to take effect through natural selection, improving the breed.
"That's the problem with mercy, kid... It just ain't professional" - Fast Eddie, The Color of Money