One,
All your "speculative" words were there to propose a scenario and imagine how it would play out. I'm not saying this exact scenario happened with humans. I was describing a theoretical mechanism of evolution. Here's a similar scenario:
Genetic Drift and the Founder Effect: | |
Eastern Pennsylvania is home to beautiful farmlands and countryside, but it's also a gold mine of information for geneticists, who have studied the region's Amish culture for decades. Because of their closed population stemming from a small number of German immigrants -- about 200 individuals -- the Amish carry unusual concentrations of gene mutations that cause a number of otherwise rare inherited disorders, including forms of dwarfism. |
http://www.pbs.org/wgbh/evolution/library/06/3/l_063_03.html
SNG