I can't even begin to point out how dumb this part of your statement is. The Jurassic period was full of animals that were not particularly intelligent, but operated largely on instinct. The cultures you are referring to don't act on instinct at all. They act on how they were raised by their parents and according to their religion. Second, 3,500 years is virtually nothing in the span of evolutionary processes. Yes, traits can change and micro-evolution occurs on the genetic level, but you don't see drastic phenotypic changes in that short a time, especially on the functional level.