What global spatial patterns are apparent in the distribution of ethnic groups? how has geography both shaped and been influenced by that distribution?

There are racial and ethnic differences in Blood type and composition. We use thiese parameters to show differences, purities and migration.
The ABO Blood group system was discovered in 1901 and since it is of major importance in medicine. 

Maybe a horizontal because its a pattern

Master planned communities outside of chicago. note: population density means people living in an area per square mile. chicago, an urban and highly populated area has a much more higher density than a desert, amish community, settlement, or nomadic region.