Fig. (4) Exhibit in the American Museum of Natural History showing the popular “ground up” (“gravity-resisted”) theory for avian flight origins, largely advocated by Smith et al. [5]. The bird-like (3.4 m, 73 kg) mid-Cretaceous maniraptoran Deinonychus is shown as part of a series of theropods leading to birds, and the exhibit notes: “The similarities between Deinonychus and early bird skeletons show that modern-day birds descended from small dinosaurs.” In reality, it is much more probable that the Middle Cretaceous Deinonychus is derived within the maniraptoran lineage. This exhibit in no way supports the view expressed by Smith et al. [5] that the field has moved beyond the distinction of ground-up vs trees-down flight origins. Clearly, this exhibit is designed to show that the ground-up “gravity-resisted” model of flight origins is that favored today by the American Museum and the majority of paleontologists, to accommodate the cladogram. (reproduced with permission, American Museum of Natural History, courtesy Shilpa Patel; copyright Denis Finnin, AMNH).