An earth shattering fart

From reading "A Sound of Thunder" what I learned is that if you go back to the past one small change can affect the future real badly. If we kill a animal in the past if could affect the future by that animal we killed the family that it was supposed to have won't be alive and that could affect the food chain in the wild life. So with one change can affect the world leading to disaster. So basically the story says that everything has a affect no matter how small it is.