UNITED STATES - AUGUST 29: A full-sized model of Lucy, the 3.2 million-year-old member of the Australopithecus afarensis, is displayed at the Houston Museum of Natural Science in Houston, Texas, Wednesday, August, 29, 2007. The Houston Museum of Natural Science worked six years to bring the fossil bones of a hominid known as Lucy to town, and it's drawing flak for its efforts. (Photo by Craig Hartley/Bloomberg via Getty Images)
