For PUNdit - a chart I posted in GQ that agrees with your comments on primates:
A chart in this biology book (Curtis & Barnes) compares Lemur, Chimpanzee and
Human development:
Gestation: roughly the same
Infancy:
Lemur-9 months
Chimp-3-4 years
Human-4-5 years
Juvenile phase:
Lemur-1 year
Chimp-6 years
Human-12-13 years
Adult phase:
Lemur-20 years
Chimp-18 years
Human-15 plus years
(I don’t know why the adult phase of the Human is listed as 15+ years, it may have been a way to make the chart/histogram “look” better or world average or something - anyway it is the growth areas that interested me.)
Did anyone else see that recent Scientific American Frontiers episode on PBS, about extending the human lifespan?
One researcher had altered the genes of some microscopic worms so that certain hormone receptors were malformed. This not only doubled the lifespans of the worms from 2 weeks to 4 weeks, but also doubled the amount of time during that lifespan in which the worms stayed vibrant, energetic adults (before they became geriatric sticks-in-the-mud).
One thing that was not mentioned was whether this genetic alteration also doubled the time it took for the worms to reach the age of reproduction (i.e. worm puberty). If it did, that would explain why the gene had been selected against in the wild – as others in this thread have noted, a short period from conception to reproduction increases the chances that the organism will survive to reproduce.
The truth, as always, is more complicated than that.