Julian658 wrote:The last place to receive humans due to migration was the Americas. It remained free of people till just the other day, perhaps 15,000 years ago, I do not recall. As to why they did not develop the same technology as Asia is not clear.
I can answer that, having studied this question intensively.
The fundamental reason has to do with climate. If you look at a rainfall map of North America for the Summer months, you will notice something. The continent gets very little precipitation during the warm part of the year. This is of immense importance when it comes to potential for agriculture. (Before widespread technology of irrigation)
Some of the parts of the continent that do get higher rainfall levels also can get very hot temperatures, leading to evaporative loses and drought.
In addition to that, there is the cold. So even in some of the lusher greener parts of the continent, the cold still greatly limits the length of the growing season.
It is much more complex than this, of course, but that is as simple of an explanation as can easily fit here.
I suspect that environmental factors and the genetic pool of a population may likely be connected, due to long-term evolutionary selection over many generations. So environmental factors could have had both direct, and indirect effects on the economic state of a population area.