dsv writes:
It would be interesting to see if there were some suggestions on improving current design, for the human body for example.
How about this Scientific American article, abstract below.
If Humans Were Built to Last; March 2001; by S. Jay Olshansky, Bruce A. Carnes, Robert N. Butler; 6 page(s)
"Bulging disks, fragile bones, fractured hips, torn ligaments, varicose veins, cataracts, hearing loss, hernias and hemorrhoids: the list of bodily malfunctions that plague us as we age is long and all too familiar. Why do we fall apart just as we reach what should be the prime of life?
The living machines we call our bodies deteriorate because they were not designed for extended operation and because we now push them to function long past their warranty period. The human body is artistically beautiful and worthy of all the wonder and amazement it invokes. But from an engineer's perspective, it is a complex network of bones, muscles, tendons, valves and joints that are directly analogous to the fallible pulleys, pumps, levers and hinges in machines. As we plunge further into our postreproductive years, our joints and other anatomical features that serve us well or cause no problems at younger ages reveal their imperfections. They wear out or otherwise contribute to the health problems that become common in the later years."
I think the reasons we haven't evolved better physical bodies and functionality to live longer are at least two fold.
We already live well past the age when we have reproduced (if we are going to) and provided parental care.
Natural selection does not act on traits post-reproductive age - there is no fitness gained from any improvements at this pont.
Secondly, we are tied into a number of inferior bone arrangements for upright walking, as described in the article, because we evolved originally as quadrupeds, and there are other evolutionary constraints that prevent us from evolving what might be significant funcational 'improvements' given our current way of life.
So, if we were 'designed', it certainly wasn't the best design for living as long as most of us are now.