Archaeopteryx weak flight abilities. "Archaeopteryx" continues to play an important part in scientific debates about the origin and evolution of birds. Some scientists see it as a semi-arboreal climbing animal, following the idea that birds evolved from tree-dwelling gliders (the "trees down" hypothesis for the evolution of flight proposed by O. C. Marsh). Other scientists see "Archaeopteryx" as running quickly along the ground, supporting the idea that birds evolved flight by running (the "ground up" hypothesis proposed by Samuel Wendell Williston). Still others suggest that "Archaeopteryx" might have been at home both in the trees and on the ground, like modern
Specimens of Archaeopteryx Pohl, who was able to find an anonymous donor willing to offer up the funds. After an initial period of display and scientific study in Germany, the specimen would then be given to the WDC on a long-term loan. After a period of research (Mayr et al. 2005, 2007), the fossil was transferred to the Wyoming Dinosaur Center of Thermopolis, Wyoming, where it has remained since June 2007. The export out of Germany of this specimen—widely considered to be one of the best "Archaeopteryx" fossils known—has caused some concern among German paleontologists and the public. Though no formal legality was