All modern birds, from ostriches to sparrows, are neornithes. (walking dinosaur costume)These differ in a number of respects from enantiornithians. and are more advanced than odontornithes. Neornithes come in two basic g4res, paleognathus and neognathus. The flrst includes the ostriches, emus, and other big ratites, plus the pheasant-like tinamous of South America. These have vaguely protobird-like, unsophisticated mouth roofs, are still somewhat protobird-like in the hips, and are especially protobird-like in their ankles. Whether paleognathus birds are anatural group, or are in part or all descendants of advanced birds that have reverted to the primitive condition, is a matter of much controversy.
The first view seems to be winning out. (realistic dinosaur costume)The second neornithian group is the neognathus birds, the fully advanced birds that make up all but a handful of the living species. With their sophisticated, hinge-jointed palates, there is little doubt that they form a monophyletic clade. However, in trying to sort out relationships within the neognathes, the 8700 or so living species and many more extinct ones pose a daunting taxonomic challenge that will take decades to work out. Many of the major bird groups have not been studied with modern techniques, and the vastness of the available data combined with the many gaps in the fossil record is overwhelming.
We have a much better understanding of how predatory dinosaurs and birds evolved and were related to each other than we did just a few years ago. (animatronic dinosaur)There is very little doubt that birds are the descendants of these dinosaurs. Big questions remain, however, many of which may be impossible to resolve. And more will arise as new species are found and old ones are reconsidered. Because we know more about predatory dinosaur phylogeny, we are able to construct more realistic classifications. But will a consensus emerge and dinosaur systematics restabilize? I really do not know, but I have hopes.