How Many Generations of Man?

[BrokenVisage]

Putting aside all the religious mumbo-jumbo about how/when man and this world were created, how many generations do you think we've gone through before getting to this point? The closest guess I came up with on the web was 125,000 which sounds insane when you figure only a couple generations could span a century, meaning there could only be about 10-15 going back to the 1700's alone, not even a significant fraction of a percentage of how many there have been. It's just such a hard notion to wrap your head around to think it had to start at some point, but because it happened so long along we'll probably never be able to figure it out.

 

[Canai]

I'd think that the figure would be even higher, given that the average life expectancy of humans is climbing like crazy. Back in the day (2000 years or so), wasn't the average life expectancy under 30?

(I just pulled that number out of my ass. History is not my strong suit )

 

[FoBoT]

get mr peabody to check it with his way back machine

 

[warmodder]

If you just take a rough estimate of 60 for an average life span, you get about 33 generations for AD. Before that, I think it may be much harder to figure because of a rapidly decreasing life span.

 

[Throckmorton]

A generation isn't a life span AFAIK, but more like 20-30 years. It would have been more like 12-20 long ago. Remember your parents are the generation before yours, but they aren't 70 years older even though that's the average life expectancy now. At a certain age you can't reproduce anymore either.

And it depends on when you consider a hominid a human. Evolution is gradual so it's not like there ever was a first human.

 

[Throckmorton]

http://en.wikipedia.org/wiki/Human

The most widely accepted view among current anthropologists is that Homo sapiens originated in the African savanna around 200,000 BP (Before Present)

If you assume 20 years for a generation, which seems pretty average, that's 10,000 generations.

Edit: Also, in hunter-gatherer times life expectancy and childbearing age would have been pretty comparable to our own. Agriculture and later civilization is what caused massive drop in life expectancy because of poorer nutrition, easy spread of disease, and maybe war.