X-Raying an Archaeopteryx
Science | Mon, Dec 15, 2008 at 5:57:08 pm PST
Scientists at Stanford are doing some interesting research into the evolution of birds, using the latest X-ray technology and an archaeopteryx fossil originally discovered in Germany: Stanford scientists scan birdlike dinosaur for evolution clues.
Stanford scientists are using powerful X-ray beams on a rare feathered dinosaur that perished more than 150 million years ago in an effort to see its inner tissues and perhaps someday understand the anatomical split that sent birds and reptiles down different evolutionary paths.
At SLAC’s Stanford Synchrotron Radiation Lightsource in Menlo Park, the scientists are using the beams to scan one of the world’s most valuable fossils, delicately transported by pickup truck from its home in a Wyoming dinosaur museum.
The X-rays, generated by a particle accelerator, cause tiny amounts of a dozen chemicals to glow without harming the ancient fossil, believed to be the earliest representation of a bird.
Scientists hope the chemicals will correlate with organs, blood vessels and other interior parts of the creature, called archaeopteryx, or “ancient wing,” which has both reptilian and avian features. When compared with scans of other fossils, such anatomical information could help explain evolutionary changes.
“What we are hoping is that we will learn more information than just what you can see with your eyes,” said Uwe Bergmann, staff scientist at SSRL. “The body decays, but the chemical elements — silicon, calcium, potassium, iron, all the chemicals which make up living animals — some of them will be preserved.”
What is visible in stone is just a faint imprint of a physical feature, such as a feather, he said. But tissues have unique chemical characteristics that aid in their identification. For instance, calcium would suggest a bone; iron might mean blood. By measuring the distribution of these chemicals in a fossil, it may be possible to re-create anatomy — and hence, evolution.
