Why do we grow old?
Why have we evolved so many wonderful mechanisms to grow and compete in this biosphere, yet have not overcome ageing?
Because – it isn’t possible to evolve anti-ageing mechanisms.
Darwinian mechanisms select out those traits that deliver a survival advantage to a given gene pool. Any trait that can more successfully deliver offspring into adulthood in safety and in numbers will be perpetuated; but traits that do not do this, no matter how otherwise desirable from an individual’s perspective, cannot be selected.
Biologically, once we have sired some children (barring contemporary societal intervention, this would naturally occur from ages 15 to 25) and have seen these children attain procreative adulthood (another 15-25 years) and then have helped out with a bit of grand-parenting (taking us through to, say, 60 years of age) we are biologically redundant.
All things being equal, having a gene allowing a 60-year-old to live to 120 would not confer any survival and procreative difference to the descendents that 60-year-old would have sired up to that point.
Therefore, there’s been no evolutionary pressure to promulgate any genes that may have arisen, over countless millenia, to ameliorate the otherwise chaotic effects of ageing.
From the perspective of each of us individually, therefore, evolution has this fatal (for us) flaw.
It is as though, after 60, Mother Nature doesn’t love us any more.
But sometimes having a little cosmetic treatment can help you put this out of your mind for a time.