The Zookeeper Collection includes the core Zoo Tycoon 2 game as well as the first two expansions. It was replaced by the Ultimate Collection in 2008 which includes the core game and all expansions.
Zoo Tycoon | Dinosaur Digs | Marine Mania | Complete Collection
Zoo Tycoon 2 | Endangered Species | African Adventure | Dino Danger Pack | Marine Mania | Extinct Animals |Zookeeper Collection | Ultimate Collection
Zoo Tycoon DS | Zoo Tycoon 2 DS | Zoo Tycoon (2013) | Friends