Ray Bradbury

Ray Bradbury
The movie poster for the film based on Bradbury's "A Sound of Thunder" depicts the butterfly whose inadvertent destruction caused so much trouble.

First reference:	Fallout
"Ray Bradbury" on Wikipedia

Ray Bradbury is an American fiction writer, and is known for dozens of novels concerning aspects of space and time travel.

About

In a Midland motel room, Hiro and Ando watch Isaac painting Hiro and the Dinosaur. Hiro worries that stepping on a bug could change the entire course of time.

"Change history? You're gonna die!" - Ando Masahashi

In one of Hiro's blog entries, Hiro says, "Do you believe in the Butterfly Effect? I do. Nobody has to see the future I saw. The future can be changed. That is my destiny."
In another entry, Hiro wonders, "What happens if I step on a bug? Will it change history? Will I no longer exist?"
In a cryptic blog entry, Hiro says, "Many butterflies cause too much chaos. One flap, precise catalyst."

In the 1952 story by Ray Bradbury, A Sound of Thunder, a group of big game hunters travels back in time to hunt dinosaurs for sport. During an expedition, one hunter falls off of the designated path, and accidentally crushes the world's first butterfly. When the party returns to the present, they find a joyless world run by a fascist dictator.
The term "butterfly effect" is the term for describing the outcome resulting from small changes in initial conditions in a chaotic system. Typically, the effect is described using the real-life example of a butterfly flapping its wings which could be the initial momentum that eventually causes a hurricane. The term has been popularized in modern entertainment as a method of describing the effects of time travel (the "mutable timeline" theory). Ray Bradbury's usage of the butterfly predates this scientific theory by about 10 years, and its naming is a coincidence.
The script for the Heroes Comic Con comic contest references A Sound of Thunder heavily.