[Sciolist]

[ QUOTE ]
Inability to sleep at will is sort of dependent on the person. Some of us certainly can do this. I suspect earlier man was able to do this even more easily. I think at least two factors have made it more difficult. (1) electricity - melatonin levels are important in allowing us to go to bed and these get screwy with conflicting messages of whether it is light or not, (2) decrease in physical activity on average - when we were busy chasing rabbits and other animals all day or fighting off the bigger animals, we experienced physical tiredness. Many, many people today simply don't have this sort of physical exertion as a normal part of their life

[/ QUOTE ]
I think the idea was more that you couldn't just sit down and say "ok, let's sleep", no matter what the time of the day, rather than talking about regular sleep patterns.

[ QUOTE ]
2. Limited number of eggs for the ladies. Why in the world do women have a limited number of eggs while men have unlimited aquamen? I really don't see any advantage to having a truncated period of fertility. Many asexual organisms don't have this same limitation.

[/ QUOTE ]
It looks a lot like you'll know more about this than me, but does this often cause a problem? As there's a limit amount of time that women can breed (particularly a thousand years ago when average lifespan was under 30), I would have thought this would never be hit, so evolution had no reason to fix it. Presumably fishies are a lot easier to build than eggs?