Ralph urges everyone to build huts for shelter, so they have somewhere to sleep at night. This symbolizes civilization because they are trying to survive and they know to do that, they have to have shelter.
KILL THE BEAST! SLIT IS THROAT! SPILL HIS BLOOD
Piggy and Ralph find the conch shell. This symbolizes civilization because they use the conch shell to hold meetings and along with the shell comes a set of rules.
WHERE ARE MY GLASSES!!!
The school boys use Piggy's glasses to build a rescue fire. This symbolizes civilization because they realize they need the fire to get rescued and they devise a plan to make sure people keep it lit.
GET BACK HERE RALPH
The school boys accidentally kill Simon, when he is mistaken for the beast. This symbolizes savagery because the school boys have gone insane and didn't even realize that Simon wasn't the beast and they proceeded to kill him.
Piggy is killed after his glasses are stolen. This symbolizes savagery because it resulted in Piggy's death. If the boy had worked together they could've earned piggy trust and ask to borrow his glasses for a second, instead they had to forcefully take them.
Ralph is being chased through the forest. This symbolizes savagery because at this point Jack and the boys have completely lost it, and they purposely are trying to kill Ralph.