The turtle, considered the oldest of the living reptiles first evolved around 200 million years ago. Today species of aquatic turtles can be found World Wide with the exception of Antarctica. The term "pond turtle" or ''terrapin" generally applies to those species that dwell in freshwater rivers, lakes, marshes and ponds. The pond turtle, like all species of turtle have a modified skeletal structure that includes a boney carapace, or shell for protection.