From an evolutionary standpoint, over the million years since the story begins, humans' brains have diminished; however, their senses have not. They can function underwater better, and rely more on instinct than on reason. The human life span has diminished by 30 years, and their teeth have been put to the test.
In these chapters, we learn of Jesus Ortiz, who works on the Bahia de Darwin. Ortiz has an utter admiration of the upper class, and truly believes if he works hard enough, he can be one of them. He does his best to serve the esteemed guests of the cruise; however, when MacIntosh cruelly ordered him to serve the lavish meat to the dog then get out, Ortiz slipped into disillusionment as his perceptions of the world shattered. He destroyed the ship's telephone box in rage and despair.
We learn more about Seigfried van Kleist and his brother, the Captain. Seigfried van Kleist will soon die from Huntington's chorea like his father, but the Captain will be spared, and eventually be the paternal origin of all humankind. Bobby King, the founder of the "Nature Cruise of the Century", is introduced to us, and we see how obsessed he was with filling his passenger list with stars. After the President advised people not to go on the cruise, most of those who had RSVP'd withdrew their confirmation, and Bobby King was out of luck.
It's also important to note that Vonnegut revealed that James Wait and Mary Hepburn will eventually marry, and that the narrator was killed during the building of the Bahia de Darwin and now haunts the ship.