Evolution of birds extinction event 66 million years ago, giving rise to ostriches and relatives (Paleognathae), ducks and relatives (Anseriformes), ground-living fowl (Galliformes), and “modern birds” (Neoaves). Phylogenetically, Aves is usually defined as all descendants of the most recent common ancestor of a specific modern bird species (such as the house sparrow, "Passer domesticus"), and either "Archaeopteryx", or some prehistoric species closer to Neornithes (to avoid the problems caused by the unclear relationships of "Archaeopteryx" to other theropods). If the latter classification is used then the larger group is termed Avialae. Currently, the relationship between dinosaurs, "Archaeopteryx", and modern birds is still under
Wyoming Dinosaur Center program. Wyoming Dinosaur Center The Wyoming Dinosaur Center is located in Thermopolis, Wyoming and is one of the few dinosaur museums in the world to have excavation sites within driving distance. The museum displays the Thermopolis Specimen of "Archaeopteryx", which is the only real specimen of this genus on display outside of Europe. Fifteen minutes from the museum are their many dig sites. Located on the Warm Springs Ranch, more than 10,000 bones have been discovered and excavated, most of which are either on display or stored just down the hill at the museum. One of the most notable fossil