At the beginning of the film when Doyle was hit by the book and flew backwards into the book shelf, the shelf was partially destroyed. But when his girlfriend slaps him and stands up, the shelving unit is completely untouched.
In "the book scene", when Bud is lining up in the hallway the camera cuts to Doyle and we can see he is standing with the coffee table lined up right next to him with no room to pass him. As Bud hits him, the camera changes to a view of him from behind, and we can see Bud has plenty of room to get past Doyle as the coffee table has moved.
Dr. Romulus refers to the butterflies as a rare species called Lepidoptera. Lepidoptera is the Latin name that refers to the order of insects that butterflies and moths belong to, not an individual species.