The Running Gag with Tom constantly misproncouncing "aeronaut" as "aronort", despite Becky's attempts at correcting him. He STILL hasn't learned how to say it properly by the climax of the film when the characters give themselves cool titles while chasing the comet down.
The movies versions of Cain and Abel. No sibling murders, but Cain is a leather dressed biker hoodlum, and Abel is a literal boy scout. Adam remarks that "Abel is a good boy, but if Cain had remained a bear, it would have improved him." Adam had operated under the assumption that Cain was some sort of small bear during the majority of the boy's childhood. Fridge Brilliance if you remember that Adam was never a child himself, the only other human he's ever met is Eve, and he has no idea what these whiny little things Even keeps finding are, or where they come from.
Eve's insistence at naming things in the Garden, which she does by nailing signs to everything, including Adam. When Adam tries, he accidentally nails a sign to an elephant and gets tossed into the trees for his troubles.