I always wondered this about Darwinian evolution. How quickly can genetic change take place? I mean, I know that the factors involved include survival of the fittest, and the nature of productive and self-defensive genes to replicate themselves more effectively than the genes that aren't as useful in a given niche, and so on and so forth. But just how many generations DOES it take, before you can really say that a change "must have" happened because of evolution?
For instance, in one thread a few of us mentioned the possible genetic variation of different gene pools from different continental backgrounds. One group from a warm climate, another from a cold climate, and so on. Since humans have existed for roughly 30,000 years (give or take; am I right on that number?) but have populated Europe for only half that time, does the remaining 15,000 years leave enough time for significant genetic change to have taken place there, such that "skills" in the European region were selected for in a manner that did not take place in other areas? I simply don't know if it can happen that quickly: whether that amount of time is WAY plenty extra, or if it's just right, or if it's WAY too little. Humans (in that period at least) would have made a new generation every 14 to 17 years, probably -- so, you're talking a little under 1000 generations, maybe 900? Enough to get blond hair, but enough to get mental traits?
I saw a show about the man-dog connection on the Discovery Channel. They said that the first record of domesticated dogs dates them back to 15,000 years ago, as well. But breed obsession for something other than function -- making little Kewpie the Chihuahua look cute in your handbag -- didn't start in Europe until the Victorian era. Prior to that, selective breeding by man was done for effect -- herding, or bearing loads, etc. Yet the wide variation among dogs is remarkable -- they said no other species has as much phenotype difference as canis lupus familiaris does. How can so much change have happened over an identical period of time during which humans can hardly manage to create characteristics that differentiate among Koreans and Japanese?
And then there's the question of stripper "stupidity." Is this also genetic? Have we actually "bred" a group of females who are mentally incapable of "normal" problem-solving of the day-to-day sort, but who have a remarkable set of human-management skills that allow them to manipulate gullible customers. And do members of this sub-species of female humans (A.) have a certain physical set of characteristics that necessarily go along with their mental characteristics, and (B.) have a male counter-part of some sort? Is it genetic? Could it be?
What is exactly a genetic time-scale. How many generations does it take?
It takes five.