What did the tourist do in "A Sound of Thunder" that caused global changes?

In the film "A Sound of Thunder," set in the near future, humanity has mastered time travel, turning it into a lucrative business. For a hefty fee, anyone can travel back to the Mesozoic era to hunt dinosaurs. Travis Ryer is a guide and organizer of these prehistoric safaris, ensuring that strict rules are followed. Participants must stay on a designated path to prevent any impact on the past. However, during one such expedition, an unexpected mishap occurs. A tourist accidentally steps off the path and crushes a butterfly. Upon returning to their own time, the group discovers that the world they knew has drastically changed.

This incident illustrates the "butterfly effect," a concept in chaos theory where small changes in initial conditions can lead to vastly different outcomes. The film explores the consequences of altering the past, emphasizing the interconnectedness of events and the potential for unforeseen repercussions. It serves as a cautionary tale about the responsibilities that come with powerful technologies like time travel.