Fluid Intelligence vs Crystallized Intelligence

Correct me if I'm wrong but it seems that fluid intelligence is something that we are born with while crystallized intelligence is something we acquire over time. Motivation seems to play a larger part in the latter intelligence but I'm sure it does with the former as well. I pass along an interesting blog entry from Deric Bownd's MindBlog :
http://mindblog.dericbownds.net/2008/10/different-aspects-of-human-intelligence.html