7 Major "Missing Links" Since Darwin

For the 200th anniversary of Charles Darwin's birth (February 12, 2009), National Geographic News asked leading scientists for their picks of the most important fossils that show evolution in action—seven of which are presented here, starting with this "fishapod." Discovered in Arctic Canada in 2004, 375 million-year-old Tiktaalik had not only gills and scales but traits of a tetrapod (four-legged land animal), including limblike fins, ribs, a flexible neck, and a croc-shaped head.