Which quotes from the novel Lord of the Flies best illustrate the breakdown of social order on the island?

In Chapter 8, Jack says that he quits Ralph's group and runs off to the other end of the island to start his own tribe. Shortly after Jack leaves, the majority of the boys follow him and decide to join his tribe. Ralph is extremely upset to see how many boys abandoned the group and has a discussion with Piggy about why the social order has been declining. Ralph mentions that he is scared and says,

"Not of the beast. I mean I’m scared of that too. But nobody else understands about the fire. If someone threw you a rope when you were drowning. If a doctor said take this because if you don’t take it you’ll die—you would, wouldn’t you? I mean?" (Golding 200).

Ralph cannot comprehend how Jack and his band do not care about being rescued. They are not concerned about maintaining a signal fire and choose to hunt rather than be civil. The boys' disregard for maintaining a signal fire and Ralph's frustration illustrate the breakdown of social order on the island.

In Chapter 11, Ralph, Piggy, and Samneric travel to Castle Rock to retrieve Piggy's stolen glasses. While Ralph is speaking with Jack, Roger hurls a giant boulder towards Piggy. Golding writes,

"The rock struck Piggy a glancing blow from chin to knee; the conch exploded into a thousand white fragments and ceased to exist. Piggy, saying nothing, with no time for even a grunt, traveled through the air sideways from the rock, turning over as he went" (260).

The rock not only kills Piggy but also destroys the conch which is a symbol of civility and democracy. This scene depicts how depraved and barbaric the boys have become on the island. With the destruction of the conch, there is no longer any hope for civilization on the island which illustrates the extensive breakdown of social order.