Although located in one of the harshest climates in the world, Alaska's arctic tundra teems with life.Frozen for nine months each year, the arctic tundra's ground never completely thaws.During the short three-month summer, thousands of birds and animals migrate to the challenging ecosystem to feed and mate.Though the plants and animals of the arctic tundra are hearty enough to survive the severe conditions, there are a limited number of species.Because...