What does geographic isolation lead to?

Incestual tendencies and hemopheliaWhat does geographic isolation lead to?
Biologically, it leads to speciation.





Culturally, it leads to stasis.What does geographic isolation lead to?
Geographic isolation leads to either stagnation (biologically, economically, socially, and technologically) or extermination, and often both.





For starters, a group existing in geographic isolation will either adapt to it or die off. Provided they are able to adapt and they they will more or less achieve an equillibrium with their environment where they do what is necessary to survive and live reasonably comfortably. Once they have achieved this equilibrium however they will stagnate because there is no impetus for further development and adaptation.





This represents a serious danger to the group however should their situation change. If there is a dramatic climate/conditions change then they will be faced once again with adaptation of extermination, often with unpleasant consequences.





For reference, see the dinosaurs, perfectly adapted to their world and then their world changed and out they went.





Another danger is the end of that isolation. Because the group has existed in isolation they have biologically stagnated, particularly in regards to its resistance to diseases. As such, when new microbes are introduced they will have little resistence too it and thus be exterminated.





For reference to this, see the mass extermination of native Americans in both north AND south America following contact with Eurasians. The same also applies to the stone age tribes in new guinea and throughout the pacific islands, australia, and even the iron age tribes in Africa.





These consequences are as true for cultural norms as they are for biological ones. Culture in this case encompassing economic, social, and technological norms. History shows, time and again, that groups that exist within a bubble come out far worse off once that bubble is broken.





For reference... just look at world history from the ancient to the modern. It is EXTREMELY rare for cultures that exist in isolation to come off the better once that isolation is broken. Even the most successful, Japan, was still harsh and resulted in a total reworking of their culture so that it bears little more than surface resemblance to its ancient roots.
Inbreeding.