In Ray Bradbury's short story "A Sound of Thunder," the butterfly that Eckels steps on serves as a powerful symbol that underscores the theme of the interconnectedness of events and the fragility of time. The story revolves around a time travel expedition to the prehistoric past, where hunters are warned to avoid altering anything in the environment.
When Eckels accidentally steps on a butterfly, it seems like a small, inconsequential action. However, this seemingly trivial mistake leads to catastrophic consequences in the present day, illustrating the "butterfly effect" — the idea that small changes can lead to significant and unpredictable outcomes. The death of the butterfly triggers a chain reaction that dramatically alters the trajectory of evolution, resulting in a drastically changed future.
The butterfly's role in the story emphasizes the theme of the consequences of human actions. It serves as a reminder that even the smallest decisions can have profound impacts on the world. This theme is reinforced by the contrast between Eckels's casual disregard for the butterfly and the devastating repercussions that follow. In essence, the butterfly symbolizes the delicate balance of nature and the importance of responsibility and awareness in the face of technological advancement and ambition.