i think that the island was once part of the garden of eden. though it might not be what the writers had in mind it is the best explainationreasons to believe this
-in season 6 it is revealed that at the heart of the island is a supernatural source of light that is vital to the rest of the world as is the root of all the supernatural things that happen on the island.
-the island can move and was once in the mediteranean most likely near egypt and Israel. this is where all the egyptian symbols and temples come from and the statue of tartet as it can be assumed that egyptians once inhabited the island . as well as in Across the Sea they speak latin so the Jacob and the man in black and their birth mother where of mediteraenen descent maybe romans. it would be most likely that the island was still in the mediteraen during this time because it would be difficult to believe in this time that these people would be halfway across the world in the pacific.
-also a major theme on the island is mans battle between Light and darkness. this is a major aspect in the story of the garden of Eden.
-Biblically the garden of Eden is in the land of Israel roughly from
the euphrates river to the nile river.
Genesis 2:10 A river watering the garden flowed from Eden..that is what we see on the heart of the Island, a river flowing from it, or from the light sourceso we know that the island has supernatural qualities and holds a light source of the world and the island has assocciations with the battle between Good and evil. and we know the island was formally located near the region of Israel and Egypt where the Garden of Eden is/was.

Why does Jacob ask his "brother" if he wants fish for breakfast when his "brother" is the Smoke Monster? Why would a Smoke Monster eat food? It makes me think that Jacob is playing along with Smokey either because has no choice but to live with him/it and it's better to placate Smokey, or that Jacob's also gone crazy living alone on the Island for centuries. :)