[blam]

"Does he give his source or any supporting rationale for it?

"How did he come up with that number? The number seems to small to sustain genetic viablity, when you look at the area we are talking about."

He does qoute a source, I just can't figure out which one relates to this number(to many to list all), here's how it was used:

"In 13,000BC the world's hunter-gather population was approaching eight and a half million. For tens of thousands of years, the growth rate had been roughly 0.0015 percent per year as our remote ancestors expanded into deserts,tropical forests and arctic regions....."

In a footnote he adds this: "This rate would increase to 0.1 percent after farming began in 9,000BC, and to 0.6 percent and 2.0 percent in the nineteenth and twentieth centuries AD, respectively."

I will add also, after the Toba explosion 75,000 years ago, I read one estimate that the worldwide human population was as low as 5,000. Toba was almost a human extinction event.

[Little Bill]

All the land areas in the world, as many of us believe, had some population in the period we are discussing, the 8.5 million is too small a number. To remain vialable a population needs a genetic infusion now and then, exogamy and wife stealing were two popular methods.

In order to expand territory you must breed above replacemant level. Hunter gatherers and hearders typically range over the same territory and when the populstion gets too large they either split and emigrate or they drive their neighbors away and their neighbors emigrate.

I think that the numbers that you quoted, for after the Toba explosion were much too small.