Macro-evolution is kind of a slippery term. Individuals have mutations which are selected. Macro evolution, or above the species level evolution, occurs the same way - except a group speciates from another group.
Creationists often think that macroevolution is saltation, or macro-mutations. It is not.
On another note, irreducible complexity is another nebulous term. It seems to be an appeal to ignorance, at it's base. We don't know how something evolved, therefore it couldn't have evolved.
Well, that might be true - but it isn't a show stopper, since it's not a positive position. It's simply a gap in knowledge. I haven't looked into these things in a few years, but as far as I know, all of the IC structures that Behe claimed were IC, have been reducible. Behe, btw, accepted common descent.