Icons of evolution don't come much uglier than Tiktaalik, the land-walking ancient fish from 375 million years ago. (See: "Our Fishy Ancestors Had Fins Made for Walking.")

But Tiktaalik was acclaimed as a beautiful scientific discovery when it was announced in 2006 by paleontologist Neil Shubin and his team. The project was partially supported by the National Geographic Society.

Unearthed in the Canadian Arctic, the fossil "fishapod" once flopped on land with surprisingly agile fins and a flexible neck, a forerunner to today's four-limbed land animals. (Related: "How We Got on Land, Bone by Bone.")

National Geographic caught up with the University of Chicago's Shubin, who unreels the story in a three-part series based on his best-selling book, Your