A couple of posts ago I linked to a post by PZ on the fact that it's populations that evolve, not individuals.
Now he's written an extended article that starts there - & morphs into a lovely piece on the evolutionary history of elephants. Complete with great illustrations of their phylogenies. Superb stuff.
PS to put it in context, this whole elephant thing was kicked off (as alluded to in one of the comments threads) by a creationist argument that evolution couldn't really work because how could it produce both male & female elephants... Which shows a lack of understanding of that original point, that it's populations that evolve.