Natural Selection

Natural Selection is the fourth episode of Survivor: Ghost Island.

Challenges
Reward Challenge: Cannon Ski-Ball Standing at the top of each tower, two members of each tribe will roll cannon balls down a long steep chute. While two other members will use ropes in an attempt to aim the chute trying to break one of the other tribe’s tiles. The first tribe to break all five of the other tribe’s tiles will win reward.

Reward: Sandwiches, chips, and drinks delivered to camp. Winners in order of finish:

Immunity Challenge: Deep In Thought On a floating platform, tribe members, one by one, must dive down and retrieve eight wheel-shaped puzzle pieces that are clipped underwater. Once all are collected, they must identify the mystery eight-letter word ("treasure"). First tribe to finish wins immunity. Winner:

Author's Notes

 * The reward challenge is the same challenge from Survivor: Nicaragua episode, What Goes Around, Comes Around.
 * The immunity challenge is the same challenge from Survivor: Philippines episode, This Isn't a 'We' Game.