Earth Sciences 1083F/G Lecture : Lecture 25 - Origin of Birds
25 Jan 2012
School
Department
Course
Professor
Document Summary
Y discovery of feathered dinosaurs in liaoning, china, excited many. Lecture 25 the origin of birds paleontologists who suspected a direct link between dinosaurs and birds: the fuzzy raptor , dates back to the discovery of archaeopteryx in the upper jurassic. hands vs. wings y some modern birds retain three fingers in a hand prior to the development of the adult wing. hand morphology: most bones in hands fuse. pygostyle ( parson s nose ) y reduced tail y air sacks within bones y no longer need long tail for balance. hollow bones y supported by thin struts like scaffolding y makes bones incredibly lightweight and remarkably: differences strong. did birds arise from dinosaurs or from thecodants? y debated y origin of flight in birds: arboreal hypothesis: transition from parachuting to gliding, then to flapping and powered flight.
