Two interesting symbols to compare would be Piggy’s glasses and the pig.
I chose these two symbols as suggestions for you because I see them as contrasting visions of society. On the one hand we have Piggy’s glasses, which symbolize civilization, intelligence, and technology. On the other hand we have the pig, which symbolizes violence, barbarism, and death. Here’s the rub: BOTH symbols also stand for survival. This makes them especially interesting to compare.
First of all, Piggy’s glasses have several layers of significance. They are a symbol of the world the boys came from. They represent his intelligence, as we are often accustomed of consider spectacles signs of wisdom or smarts. Piggy is one of the few boys on the island that seems to think things through, and often makes connections back to the outside world in his suggestions.
The glasses are also important because the boys desperately need them for fire.
His specs–use them as burning glasses!”
Piggy was surrounded before he could back away.
“Here–let me go!” His voice rose to a shriek of terror as Jack snatched the glasses off his face. (ch 2)
The glasses allow the boys to make a signal fire, as well as fires to cook the meat. The fire is so important to their survival and as a connection to the outside world that Jack actually steals them from Piggy when the two factions split. It is not long after that the boulder is rolled onto Piggy.
The pig is a symbol of violence from the very beginning. When Jack, Ralph, and Simon first encounter the piglet, even the violent Jack is repulsed at the thought of killing it, despite the fact that Jack and Ralph both say they know what to do. Ralph wants to stick it, and Jack wants to slit its throat and let the blood drain out.
“Why didn’t you—?”
They knew very well why he hadn’t: because of the enormity of the knife descending and cutting into living flesh; because of the unbearable blood. (ch 1)
Later, the boys have a very different response to the pig. All they can think about is hunting them. They use it as the foundation of their new barbaric culture, including painting their bodies and chanting as they do a pig dance.
“Kill the pig. Cut her throat. Spill her blood.” (ch 4)
What initially was just a practical act of spilling blood to avoid spoiling meat becomes symbolic, and the pigs head is left in the woods as an offering. Ralph tries to argue that keeping the fire going so that they can get rescued is more important than killing pigs. Jack does not listen. Ultimately, pig-killing is directly or indirectly responsible for the deaths of both Simon and Piggy, whose ironic name and lack of glasses doom him.