(A) Best-practice life expectancy (that is, the best life expectancy reported by any country) and life expectancy for women in selected countries, 1840–2007. Reproduced with permission from the Lancet (2). (B) Life expectancy at birth for Homo sapiens from 200,000 BCE to the present, separated into prescientific (200,000 BCE until 1840) and scientific (1840 until the present) eras.