why would people of European descent in the late 1600s begin to believe that people of African descent were naturally or biologically inferior to them​

Because of the White Man Burden.

Explanation:

The white mans burden was the beliesf that it was white mans duty to colonize others

It is a prairie region, much like the Black Belt. While the Jackson Prairie has more trees and soil that is not as rich as the Black Belt, it is still good for growing crops, raising cattle and growing pine trees.