New York, NY —
Human evolution is often portrayed as a step-by-step progression from ape to man. But the newly renovated Hall of Human Origins at the American Museum of Natural History doesn’t look anything like that. WNYC’s Beth Fertig has more.
REPORTER: You probably remember them from the museum’s old dioramas. A pair of fuzzy, pre-human ancestors walking arm in arm across the African plains. But those lifelike icons have finally been released from their spot on the museum’s wall.
HARVEY: Everyone who comes in marvels at this sort of miniature quality of these very hairy australopithecines.
REPORTER: David Harvey is the museum’s vice president for exhibitions, and the australopithecine is better known as “Lucy.” That’s the nickname for the oldest known pre-human skeleton, discovered about thirty years ago. Today, the life-size replicas stand about three feet high in a glass case at the center of the new exhibit.
HARVEY: They’re in our world for a moment. Rather than us peering into their world. And that really is a motif of the hall. That we are bringing our past into our present.
REPORTER: The Hall of Human Origins was funded by Governor Spitzer’s parents – Anne and Bernard Spitzer. It includes a reconstructed Neanderthal skeleton that was painstakingly created from the pieces of six different specimens. There’s also a rare sample of Neanderthal DNA taken from a fossil. It looks like a wisp of smoke in a test tube. This the first major evolution exhibit combining fossils with genetics. Curator Ian Tattersall says a lot of this stuff wasn’t around when the museum last updated its evolution hall in 1993.
TATTERSALL: We have maybe 50% more fossils that we’re able to display in this hall than we had 15 yrs ago. And the other aspect is we’ve had this opportunity to integrate the story told by the fossils with this story told by the molecules.
REPORTER: The molecules get equal billing. We learn about two different types of DNA and how they were passed on over hundreds of millions of years. Curator Rob DeSalle, of the museum’s comparative genomics department, points to a big tree of life that shows how everything is related.
DESALLE: Because genes for certain functions exist in all organisms on the planet, all the way from bacteria to mammals and to higher vertebrates, we can use those genes to trace history.
REPORTER: Tracing DNA enabled scientists to prove that human beings migrated from Africa to Asia. They also found our closest living relative is the chimpanzee, which shares more than 98 percent of our DNA. And because we all developed from simple organisms, DeSalle says we can add some other new relations to our family tree.
DESALLE: We can also see that things like fungi, mushrooms and things that grow on the ceiling, they’re more closely related to us than they are to plants. So what we tried to do with this tree of life is show where humans come in into this great grand tree of life. They’re a little tiny speck on the top there (laughs).
The museum encourages visitors to see how scientists like DeSalle do their work. In a laboratory off to the side of the main exhibit, they can look at fossil replicas under microscopes. Monique Scott, a physical anthropologist in the education department, says students can do experiments similar to the ones scientists conduct upstairs.
SCOTT: Here for example students will be able to isolate their own DNA. So as you see here, this is actually my own DNA that I isolated from my cheek cells. And it only took about 20 minutes to do.
REPORTER: How did you get it off?
SCOTT: Surprisingly easy with detergent and salt solution. So really you take a sample of your own saliva and add some detergent and salt solution.
REPORTER: Throw in a dash of ethanol, and you’ve got a tiny white strand of DNA swirling around in a test tube, just like the ones in the hall. But the exhibit isn’t just about science. In the end, it’s asks us to consider what makes us human.
Since humans share 99 point 9 percent of their DNA, our differences – in skin color, language, and music - are puny compared to what makes us alike. In fact, the curators say human evolution has pretty much come to a halt. Doctor Tattersall says widespread genetic changes are more likely to happen in small, isolated populations - where a favorable mutation can flourish. But ever since the Ice Age bridged the seas more than 10 thousand years ago, humans have taken over the globe.
TATTERSALL: There’s 6 billion of us, the population’s getting bigger all the time, we’re unprecedentedly mobile. The conditions for the fixation of genetic novelties arising within the populations are pretty much eliminated.
REPORTER: In other words, unless we’re isolated again through some major catastrophe – or manipulate our own genes - humans have pretty much stopped changing. The Hall of Human Origins opens tomorrow at the Museum of Natural History. For WNYC I’m Beth Fertig.