AP: Civilization is steadily creeping toward the fossilized remains of animals that once roamed what is now the Mojave Desert during long-ago ice ages. The bones poke silently from chalky, beige soil where they died. Today, instead of lush plants that Columbian mammoths would munch while standing knee-deep in bubbling springs, the landscape is dotted with shrubs: creosote, buckwheat and bearpoppy plants. Helicopters routinely thunder overhead on training missions from Nellis Air …