There are 4 main human subgroups. Negroids, Caucasoids, Mongloids and Australoids. Are these groups different? Yes. But to say that these differences are significant is like saying that having the same model of car painted green instead of red makes it significantly different.
EDIT:
inb4 Collision finiding this thread, telling non-Caucasoids to GTFO and making Australians look like morons.