As William Golding's Lord of the Flies progresses, it becomes very clear that the boys are dividing themselves into two groups. The one group consists of Ralph, Piggy, and Simon, who are determined to take their situation seriously, to try and survive, and to try to be rescued. Though Ralph has been voted into being the official leader of all the boys, Ralph is really only successful in leading Piggy and Simon. Together, these three boys work very hard to build and maintain a signal fire and to build shelters; however, though Ralph is the leader, he is unable to get the other boys to tend to the signal fire or to help with building the shelters. Instead, the other boys are reckless about setting and keeping the fire, even setting trees ablaze, are only interested in hunting with Jack, and keep playing around in the lagoon. We particularly see how wild and reckless the other boys are becoming when Ralph complains to Jack about how the "littluns," and even the older boys, who are supposed to be helping to build the shelters are off playing:
They're hopeless. The older ones aren't much better. D'you see? All day I've been working with Simon. No one else. They're off bathing, or eating, or playing. (p. 70)
Hence, although Jack is not the official leader, he incites other boys to carelessness, forming the second group. What's more, Jack's group particularly starts becoming dangerous the more they become obsessed with hunting. For example, in Chapter 4, the moment Jack and his hunters are finally successful in catching a pig, Jack becomes violent to the point that he slaps Piggy and breaks his glasses, a scene that particularly foreshadows more aggression and dangers to come. Hence, as the book progresses, it's clear that the boys form two groups, one group whose goal is to survive and maintains their sense of reason and of civilization and one group whose goals are to hunt and have fun and becomes careless, giving into their more animalistic instincts.