When the main event of a card features a champion versus an unranked opponent, you can't expect a big change in the official UFC rankings when the champion wins. In fact, most of the big fights on the UFC 159 main card featured battles between guys on the charts and guys skirting the fringes. In one case, the fringe guy took out the longtime challenger (Pat Healy vs. Jim Miller) and that caused a bunch of changes. But the rest of the fights featured the favorite winning, so those divisions (light heavyweight, heavyweight, middleweight) haven't been affected much.
You can check out the full UFC official rankings here (which features like 22 BE writers on the panel).
One division that was shook up by a preliminary card fight was the women's 135 lb. weight class. Sara McMann's first-round finish of Sheila Gaff sent her up a couple of spots in the rankings in this new division. The Olympian moves from number six to number four on the challengers list, while Liz Carmouche and Alexis Davis fell a spot. Gaff also fell to number 10, being displaced by Germaine de Randamie at number nine.
As mentioned above though, it's the lightweight division that has seen the most flux as of late. New/lazy rankers have moved Josh Thomson up all the way to the number four spot on the contenders list, four spots above the eight slot he occupied last week. T.J. Grant also reaped the benefits of a Nate Diaz loss and moved from seven to six. Jim Miller (unsurprisingly) plummeted from four to eight, while Diaz managed to only drop one more spot to seven. Healy made the list at number nine (and will probably move past Miller soon, depending on the rankers), while Rafael dos Anjos managed to stay on the list at number 10.
The other two changes were pretty minor. Tim Boetsch moved into the number 10 spot at middleweight due to Alan Belcher's loss to Michael Bisping, while Roy Nelson moved into a tie for the number five spot with Alistair Overeem at heavyweight.