What is the symbolism of the island in Lord of the Flies?

In the novel, Lord of the Flies by William Golding, the island represents the microcosm of the world the boys have left behind.  The island is by itself with no other people nearby, so the boys have space to create their own ideal world. As they are civilized British boys, the reader would expect the island to be run as they have been taught--with rules, leaders etc.  However, as the reader soon learns, the island as a symbol of their world and how they will create it turns into a deadly mockery of the original idea.  As a microcosm of the "civilized world" they left behind which is currently at war, the boys soon reflect the  image of war among themselves, with two leaders, Ralph and Jack, at war with each other just as they are in the world outside of the island.  Only the navy captain's appearance at the end of the novel, saves Ralph from death, and the boys board the ship, leaving the microcosm of the island to return to the macrocosm of the world outside of the island.  Both the island and the outside world are like each other with death and destruction happening in war.