John Hammond's grandchildren Lex and Tim have the surname Murphy.
In the 1993 film Jurassic Park, Lex Murphy and Tim Murphy visit Isla Nublar with their grandfather, park founder John Hammond. They become separated from the adult visitors when the park's systems fail and the dinosaurs escape, making them central survivors of the island disaster.
The siblings' roles differ noticeably between Michael Crichton's novel and Steven Spielberg's film. In the book, Tim is the younger dinosaur expert and computer enthusiast, while Lex is younger and more athletic. The film swaps their relative ages and gives Lex the crucial computer skills used to restore the park's security systems.
Lex and Tim are sometimes confused with other Jurassic Park characters because several surnames are strongly associated with the story: Grant, Sattler, Malcolm, and Harding. Those names belong to the visiting scientists or park personnel, not Hammond's grandchildren. The surname Murphy identifies both children in the film and in the original novel.