What crops and other food sources are available has a lot to do with what directions any society can take.
Far more important that this imaginary construct called "IQ".
Guns, Germs, and Steel: The Fates of Human Societies
https://www.amazon.com/Guns-Germs-Steel-Fates-Societies/dp/0393317552/ref=sr_1_1?s=books&ie=UTF8&qid=1470953768&sr=1-1
Chapter 5: Geographical differences in the onset of food production.
Explain Iceland. Or Singapore. Or South Korea. Or Hong Kong.
In what year?
Have you read the book?
Have you ever read a book?
No need for insults, unter. I've got the book. I've read the book. (So many years ago.) And Diamond takes great pains to avoid referencing human biodiversity to explain why some societies succeeded while others didn't.