The discovery of a bizarre fossil reignites the debate over the origin of flight. With four wings, the 130 million-year-old creature is like nothing paleontologists have ever seen before. More videos:
http://dinosaurstop.com
In this program,
NOVA travels to the
Chinese stone quarry where the fossil was discovered—a famed fossil 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.
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. (Compare Microraptor's skeleton with those of the earliest known bird and a nonflying dino relative.)
But how did Microraptor use its wings? Did it 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.
In addition, NOVA commissions a "flight-ready" wind tunnel model of Microraptor complete with feathers and articulating joints. (Test-fly Microraptor yourself in a virtual wind tunnel.)
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.
The two markedly 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. (
Hear from the film's producer,
Mark Davis, on why this debate has fascinated him for two decades.)
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 bird-dinosaur 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.
As seen in this program, the
American Museum's Mark Norell 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, with the help of NOVA's model and wind tunnel tests, 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.
- published: 04 Sep 2015
- views: 9655