The derivation of the word “penguin” is probably Welsh (pen gwyn means “white head”), but that doesn’t mean that there were once penguins in the North Atlantic. According to Penguins, Puffins, and Auks: Their Lives and Behavior, the role of penguins is taken in the north by auks (which include puffins), birds that have strong behavioral similarities but no close genetic link to their southern brethren. Photographer Art Wolfe, who took the book’s fine photos of the upright-walking birds in their oft-dramatic habitats, will elaborate in a slide-illustrated lecture Tuesday at 8 p.m. at the National Zoo’s Education Building Auditorium, 3000 Connecticut Ave. NW. FREE. For reservations call (202) 673-4801. (Mark Jenkins)