[nostromo]

You're misreading the statistics a bit. The biggest gains in life expectancy have been at birth. There have been old people for a lot longer than the last 150 years.

Even Aristotle knew about menopause. And Plato lived to be 80.

[darkmighty]

You have to remember a significant time in human evolutionary scale is probably something like 10k-100k years. Looking at wiki page for life expectacy at the Paleolithic [1] (even at 15 years) shows it lines right up with woman menopause.

[1] http://en.wikipedia.org/wiki/Life_expectancy

[FeeTinesAMady]

Life expectancy is a mean value, and it's skewed by people dying young. So the life expectancy at the Paleolithic doesn't mean that people didn't survive past menopause: it means that a lot of people died young.