February 8th, 2008 12:59 EST
NOVA explores how Dinosaurs got their Wings
In 2002, the discovery of a beautiful and bizarre fossil astonished scientists and reignited the debate over the origin of flight. With four wings and superbly preserved feathers, the creature was like nothing paleontologists had ever seen before. Now, NOVA travels to the Chinese stone quarry where the fossil was discovered--a famed dinosaur treasure-trove--and teams up with the world's leading figures in paleontology, biomechanics, aerodynamics, animation, and scientific reconstruction to perform an unorthodox experiment: a wind tunnel flight test of a scientific replica of the ancient oddity. Find out whether this 130 million-year-old relic takes flight on The Four-Winged Dinosaur, premiering Tuesday, February 26 at 8pm ET/PT on PBS (check local listings).
Dubbed Microraptor, the crow-sized fossil is one of the smallest dinosaurs ever found and one of the most controversial, challenging conventional theories and assumptions about the evolution of flight. But how did Microraptor use its wings?
Did Microraptor array its arm- and leg-mounted wings in the style of an early-20th-century biplane to produce high lift at low speed? Did it use them to create a single lifting surface for efficient, swift gliding? Did it employ some combination of these two methods? Or were the extra wings useless for flight and likely to have been for some other purpose, such as attracting a mate?
To answer these questions, NOVA interviews Chinese paleontologist Xu Xing, who first recognized the importance of Microraptor and gave it its name; paleontologist Mark Norell and artist Mick Ellison of the American Museum of Natural History; paleontologist Larry Martin of the University of Kansas; anatomist Farish Jenkins of the Museum of Comparative Zoology at Harvard University; and aerodynamicist Kenny Breuer of Brown University.
Artists have historically played an important role in paleontology by helping to reconstruct the appearance and behavior of ancient animals. In the case of Microraptor, two completely different reconstructions were made, one at the American Museum of Natural History, and the other at the University of Kansas, based on different specimens and different techniques.
In addition, NOVA commissioned a "flight-ready" wind tunnel model of Microraptor complete with feathers and articulating joints.
The different reconstructions play into a long-running scientific controversy over the origin of flight in birds. For years the debate has been a standoff between two camps--those who believe dinosaurs were the ancestors of birds, and those who do not.
Believers in the dinosaur-bird connection have generally assumed that flight must have begun from the ground up, with fast-running dinosaurs that eventually got airborne as feathered arms evolved into wings and running leaps evolved into powered flight.
Skeptics of the dinosaur-bird link say it would have been physically impossible for running dinosaurs to overcome gravity and get off the ground. It made more sense for flight to evolve from the trees down, with small, arboreal reptiles that glided from the treetops on their way to becoming full-fledged fliers. And that seemed to rule out dinosaurs, which, presumably, couldn't climb trees.
On NOVA, Mark Norell of the American Museum of Natural History is one of the proponents of the "birds-are-dinosaurs" hypothesis, which is the predominant view among most paleontologists, while Larry Martin of the University of Kansas speaks out for the minority view that birds descended from non-dinosaur tree dwellers.
Tantalizingly, Microraptor is the unexpected missing link that has reignited the debate and just might settle the issue--or at the very least deepen our understanding of the long-ago era when the ancestors of birds first took to the air.
Now in its 35th year of broadcasting, NOVA is produced for PBS by the Science Unit at WGBH Boston. The director of the WGBH Science Unit and senior executive producer of NOVA is Paula S. Apsell. Funding for NOVA is provided by David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, and public television viewers.
NOVA is closed captioned for deaf and hard-of-hearing viewers and described for people who are blind or visually impaired by the Media Access Group at WGBH. The descriptive narration is available on the SAP channel or stereo TVs and VCRs. The Four-Winged Dinosaur will be available on DVD wherever videos are sold. To order direct from WGBH Boston Video, visit shop.wgbh.org or call 800.949.8670