oh and my theory on how it got to earth:
The monkey that got lost in the beginning which sent "marky mark" after him, was never found. BUT, the whole planet of the apes did see him at one point to make him their "messiah". So he was on their planet at one time or another, but left. So while marky mark was on the monkey planet, the little monkey was no where to be found, right?. At the end, the little monkey comes back to the monkey planet and marky mark leaves in his ship. Now where has he been all that time? The time he was gone could be any amount due to the weird rules of time dealing space and space travel. So i think that he made it back to earth and planted his seed on earth. How he did it, i dont know this is only my observation. So when marky mark got back to earth, it looks the same, but probably is about 1000 or more years later than when he was on earth. So that is ample time for the same changes to take place. It mostly has to do with the wormholes that the two travel through. If you studied space at one time you would be able to let your mind run with the possibilities a little. The real question is "How in the hell did that ship's engine work?" Seemed to be a POS to me when he started it. (the engine that killed some of the monkeys in the war.)
Matt