Racism is, quite simply, the assumption of a trait based on race. This can range from assuming that black people are lazy to assuming that asian people are smart.

Virtually no race is excused from environment, which can be based on the culture surrounding that race. I'd be very, very, interested in seeing a survey of people raised by adoptive parents of a different race and then comparing those numbers against those of "traditional" families. I seriously doubt we'll ever see such a study, though, because the people who are likely to be interested in this line of study aren't interested in separating race and culture.

Also, I find it seriously hard to believe that the average Australian Aborigine is less than two-thirds as smart as the Australian of European descent living next door. I think that points more to a bias of the test than an accurate assessment of intelligence.