65:2.16

In this way the life that was planted on Urantia evolved until the ice age, when man himself first appeared and began his eventful planetary career. And this appearance of primitive man on earth during the ice age was not just an accident; it was by design. The rigors and climatic severity of the glacial era were in every way adapted to the purpose of fostering the production of a hardy type of human being with tremendous survival endowment.