After Ice Age, prehistoric animals gone, today's animals, birds, and fish inhabit the earth. The North and south poles develop during the iceage, and due to their location, they do not thaw. At least not yet. I believe the earth was one piece until the thaw, but, not being an artist, would not perform this act. The reason the earth seems to grow is that it is being observed as if from the sun. It is moving back into its present location, which was its location prior to the ice age.