Evolution favors to those animals (including human) who explores new sources of food and better living conditions in constantly changing environment. You simply die out soon or later if you do not move out of depleted/overpopulated areas or out of becoming too hostile due to climatic or other changes zones. So, struggle for survival gives advantage to those animals which have better abilities to search, to explore new horizons, to adapt to changes, to be creative in protection from elements and predators.

This is where thinking comes from - from struggle for survival, not from god(s) or Santa Clauses.

El, did we eliminate at least one GOG (god of gap in knowledge, as Harvey very correctly labeled it) from your rich imagination?