Down here at the pawn shop

[Happy Monkey]

Originally Posted by Undertoad

Our cultural differences APPEAR to be genetic, because they happen over so many generations of time that we can't see where the changes happened.

Hence the idea of "memes" evolving similarly to genetic evolution, and for the same reason - cultural groups are separated mentally like evolutionary groups are separated geographically, with some mixing along the borders, and imperfect duplication and a changing environment causing change over time.