Enlarge By Chip Clark, Jim DiLoreto, and Don Hurlbert, Smithsonian Institution Five fossil human skulls show how the shape of the face and braincase of early humans changed over the past 2.5 million years. (from left to right: Australopithecus africanus, 2.5 million years old; Homo rudolfensis, 1.9 million years old; Homo erectus, ~ 1 million years old; Homo heidelbergensis, ~350,000 years old; Homo sapiens, ~ 4,800 years old)

WASHINGTON  What could prompt a climate protest at a paleontology exhibit?

The Smithsonian's National Museum of Natural History saw this scenario, when Greenpeace protesters arrived Wednesday for the museum's opening of a state-of-the-art $20.7 million "Hall of Human Origins," exhibit.

"The guards told us they were expecting creationists," says Greenpeace's Kert Davies, instead of activists who were protesting co-funding of the permanent addition by oil billionaire David Koch. Koch (pronounced "coke"), a one-time Libertarian candidate for Vice-President, is prominent in circles opposing regulating greenhouse-gas emissions.

"We are not opposed to the Smithsonian," Davies says. "I hear the exhibit is fantastic."

Fantastic it is. A glittering time tunnel greets entrants with its portraits of early human species from the last 6 million years. Throngs of visitors take turns pawing the real-scale model skulls of humanity's ancestors, set on swivels at the entrances.The exhibit is the Smithsonian's effort to tell the story of human evolution, from the ape-like Sahelanthropus tchadensis to Homo sapiens.

Light and airy, with the wired-in feel of an Apple store (terminals and gadgets abound) instead of a stuffy cabinet of wonders, the exhibit features original artifacts such as the first Cro-Magnon man skull discovered, cast skeletons including Homo floresiensis (a.k.a. "hobbits") and Homo erectus, interactive theaters and even a vividly-recreated "cave art" wall. "They are using everything," said curator and paleoanthropologist Rick Potts, buffeted by visitors on the exhibit's second day.

A renowned paleontologist, Potts perhaps expected creationists as well, given about 39% of U.S. adults overtly reject evolution, according to a 2006 study in the journal Science. "We are a public institution, so we have to be responsive to the public," Potts says. "Our 'Broader Social Impacts Committee' includes representatives from a broad range of viewpoints, from evangelical to atheist."

Instead of lecturing, Potts says, the exhibit tries to lay out what science has found and let visitors reach their own conclusions. "What Does It Mean To Be Human?" asks the exhibit at its entrances, and in its companion book. "Too many exhibits are just textbooks, defining natural selection and then variation in a sort of march," Potts says. "We want visitors to get an intuitive feel for the changes over time we see in artifacts and other evidence."

So the exhibit walks visitors through the changing climate, environment, tools and proportions experienced by our predecessors on the planet, species like Homo erectus, from 1 million years ago, or Australopithecus afarensis, famed for the "Lucy" fossil from 3.3 million years ago. The artist John Gurche, using forensic reconstruction methods, has created some wonderful lifelike reconstructions, complete with swirling fur and hair based off living ape and human patterns, throughout the exhibition.

"I'm just staggered by the exhibition," Gurche said, taking in the early visitors enjoying the sights. Although, he confessed that as an artist he would have liked more dramatic lighting for some of his creations.

As for creationists' take on the exhibit? "I haven't really paid too much attention to it," says Ken Ham of Answers in Genesis, which runs the Creation Museum in Petersburg, Ky. Famed for its juxtaposition of people and dinosaurs, the museum promotes a literal reading of the Old Testament in its view of human and the Earth's origins. "I'm amused how much the (Smithsonian) exhibit cost. We built a whole museum for that much," Ham says.

For anyone keeping score, the Smithsonian's Hall of Human Origins measures 15,000 square feet and the Creation Museum encompasses 70,000 square feet of exhibits.

Warming to his topic, Ham called it "child abuse" for the Smithsonian to "promote the secularist view that people are just animals. So, if you are an animal, you might as well do anything you want."

The Smithsonian exhibit leaves it up to visitors to decide "what does it mean to be human," Potts says, their views shared among museum-goers, who input their two cents on the computer terminals in the middle of the hall.

Potts may have expected more controversy over the exhibit's inclusion of hobbits as a true human species. Since the discovery of the pint-sized species on the Indonesian island of Flores in bones dating to about 17,000 years ago, some paleontologists have steadfastly derided them as diseased humans, rather than another extinct branch on the tree of life.

The journal Nature this week, reported that stone tools typical of early humans have turned up on Flores, dating to more than a million years ago. "The evidence just continues to mount Homo floresiensis (hobbits) have the characteristics of a distinct species," Potts says.

So if creationists and paleontologists aren't squabbling, why is Greenpeace mad about the $15-million gift from Koch, that helped fund the exhibition?

"One strain of climate science denial is the notion that climate has changed in the past and people evolved, so climate change is no big deal," Davies says. "That ignores the rapid speed of climate change today." So Greenpeace is worried that the exhibit showing humans evolved to adapt to slowly-changing climate in the past is a subterfuge for the argument that nothing should be done about the global warming now.

Birds, farms and the rest of the environment have felt the effects of climate change over just the last few decades, according to the United States Global Change Research Program, rather than millions of years that human ancestors saw with the expansion of arid grasslands in parts of East Africa.

A spokesperson for Koch Companies Public Sector LLC, Melissa Cohlmia, said David Koch was traveling Friday, and couldn't comment on the protest.

"David Koch was not involved in any way in the development or review of content of any aspect of the human origins exhibition, the human origins initiative or any other Smithsonian Natural History Museum program. Donors do not have input into the content of exhibitions," said museum spokesman Randall Kremer, by email.

"More than 100 scientists and educators (from 48 countries) took part in planning the exhibition," Potts says. "All we want to do is showcase and demonstrate the changes that took place over time. We can't put anyone's philosophy on the wall."

For now, anyone interested can see for themselves. Incredibly enough, like all of the Smithsonian's museums, entry to the National Museum of Natural History is free. If you want to see the evidence for human evolution face-to-face, the Human Origins hall is the place to indulge that monkey-like curiosity.