Jack and Ralph argue over the use of the kids time and whether shelters and keeping the fire going are more of a priority than hunting and meat. How does the argument between Jack and Ralph symbolize or relate to the idea of desire vs. necessity?

Jack wants to indulge in his desires: he wants to hunt and he wants to play. Ralph knows things like shelters and signal fires are necessities. It is this dichotomy of desire and necessity that the boys personify throughout the story. Unfortunately most of the boys gravitate to desire. They haven't the discipline or maturity to resist the constant human appetite for desire.