Ralph and Piggy prayed for a "sign" from the grown-up world and have been given one. Explain the significance.

At the end of chapter five, Ralph and Piggy wish for a grownup sign to help them because they can feel that the structure of the group is being torn apart. Unbeknownst to the boys, a dead parachutist lands on the top of the mountain where the signal fire is kept. This is significant because a sign has been sent, but it is wrongly interpreted by the twins, Sam and Eric. They see the dead parachutist and assume that it is the beast that has finally shown itself. Instead of this sign bring hope to the boys, it brings despair and fear.