What is a key symbol that develops in the novel The Lord of the Flies?
*Per eNotes policy, I edited down your question to focus on one key symbol in the novel.
The conch appears throughout Lord of the Flies as a symbol of power and authority. Discovered in the first chapter, the conch's call summons the other boys for their first meeting on the island, and because Ralph is the possessor of the shell, the boys elect him for chief over Jack. As the novel progresses, mention of the conch appears in chapters 2, 4, 5, 6, 8, 10, and 11. Throughout all of these chapters, the conch reinforces Ralph's position as chief and instills order in the tribal meetings as the boys must take turns speaking while holding the conch. In Chapter Eleven, Golding emphasizes the conch's symbolic power as both it and Piggy are crushed by Roger's boulder:
"the conch exploded into a thousand white fragments and ceased to exist" (181).
The destruction of the conch signals the end of Ralph's authority and the last vestiges of civilization on the island.