Aug. 31 (Bloomberg) -- The Houston Museum of Natural Science worked six years to bring the fossil bones of a human ancestor known as Lucy to town, and is drawing flak for its efforts.

The exhibit of the 3.2-million-year-old bones opens today, the first time they've been displayed in public outside Ethiopia, where they were found 30 years ago. Eager museum-goers already have bought more than 3,700 tickets.

Others are less enthusiastic about Lucy's appearance in Houston, which kicks off a six-year U.S. tour. Museums including the Smithsonian Institution in Washington declined to participate. Scientists say the remains -- which showed for the first time that walking erect preceded human-like brains and the use of tools -- are at risk of being damaged, and expatriates accuse Ethiopia's government of exploitation.

``This is a form of power play by some natural history museums to boost their attendance,'' said Owen Lovejoy, a paleoanthropologist at Kent State University in Kent, Ohio, who worked on Lucy in the 1970s. ``Lucy is the only thing like it in the world. It never should have left Addis Ababa.''

Houston museum officials insist Lucy is safe in their hands. They said the 98-year-old institution has an unblemished record in handling treasures including Faberge eggs and the Dead Sea scrolls.

``Almost no object on earth is as fragile as a 2,000-year- old piece of parchment,'' said Joel Bartsch, president of the museum. ``While it's true that Lucy is very unique and very rare, and of huge importance to mankind, by museum standards she's certainly not considered fragile.''

Some museums aren't risking it.

Museum Concerns

``Lucy, as a specimen, is in our estimation too fragile to travel,'' said Randall Kremer, a spokesman for the Smithsonian. ``It is one of the most significant natural science specimens in existence. We simply do not agree with the decision to tour Lucy, and would not in any way, shape or form become involved.''

The Cleveland Museum of Natural History also declined to host the exhibit, said Marie Graf, a spokeswoman.

Lucy's bones survived eons without protection. Donald Johanson, director of Arizona State University's Institute of Human Origins in Tempe, discovered them in the fossil-rich region of Hadar, in northeastern Ethiopia, lying in the open.

``When I looked up the slope to my left, I saw some ribs, I saw some pelvis,'' he said. The geology indicated that the bones were 3 million years old, making them the most complete set of human ancestor fossils ever found from that period. Lucy consists of several hundred bones and fragments, including a partial pelvis, rib cage, arms and jaw.

`Common Ancestor'

``She occupied a very important position on the family tree as the last common ancestor for those humans who evolved into homo sapiens,'' Johanson said.

Johanson said that while he is somewhat uneasy about the possibility of damage, he doesn't oppose exhibiting Lucy because it will help raise awareness of human-origins studies.

Fossils ``are pieces of irreplaceable scientific evidence,'' said Bernard Wood, a professor of human origins at George Washington University in Washington. He spearheaded United Nations guidelines calling for fossils to be kept in the country of origin except for research.

Displaying any fossil is scientifically unwise, Kent State's Lovejoy said. Electron microscopes can detect delicate changes to bone surfaces that reveal ancient behaviors, he said.

Disproving Theory

Lucy's fame endures despite the later discovery of older fossils because her existence debunked an evolutionary theory, Johanson said.

Lucy is one of the species of hominid that occurred after the ancestral split between humans and apes. Some scientists had thought that humans grew large brains before walking upright, and needed the new posture to carry and use tools. Lucy walked upright even though she had a brain like a chimpanzee's and didn't use tools.

Houston's Ethiopian community backed the exhibit during the planning stage. It withdrew support in June, after the Houston museum declined to disclose financial details of its agreement to show the fossils and coordinate the tour.

``Most of the resources that are extracted abroad don't go to the Ethiopian people,'' said Dule Abdu, a board member of the Ethiopian Community Organization.

Houston museum officials said the institution is non-profit and has an apolitical stance.

Advance ticket sales for Lucy are running ahead of those for BodyWorlds, which was the most popular exhibit the museum has hosted, said Melodie Francis, a spokeswoman. The exhibit is open through April 20.

More Venues

The museum is arranging for Lucy to be shown at as many as 10 other sites. Bartsch declined to identify the institutions interested in participating. He said some proceeds will go to Ethiopia's museums but wouldn't say how much.

Some museums display casts of fossils in an effort to educate the public while preserving the original finds. Dirk Van Tuerenhout, the Houston museum's curator of anthropology, said the Dead Sea Scrolls are a good example of why replicas are a bad idea.

``What might have been the reaction of visitors if instead of displaying the original fragments, we informed them that we were going to display nicely framed Xerox copies?'' he said. ``How many people would have come to that? How can you teach if nobody comes?''

To contact the reporter on this story: Jim Kennett in Houston at jkennett@bloomberg.net

Last Updated: August 31, 2007 03:39 EDT