Because in modern biological classification you don't stop being a member of a group just because you start to be something new as well. In modern classification all groups are clades (monophyletic groups: an ancestor and all of its descendants, no matter how transformed).Aves didn't stop being part of Dinosauria when they became birds as well. Chiroptera didn't stop being part of Mammalia when they became bats as well. Tetrapoda didn't stop being part of Osteichthyes when they became tetrapods as well.And people say ignorant things because they are literally ignorant: they don't know that classification has changed, and so operate under an old typological-based thinking rather than genealogical-based thinking.On Mon, Apr 12, 2021 at 2:44 AM Poekilopleuron <dinosaurtom2015@seznam.cz> wrote:Good day!If you were to answer this question, how would you put it? Because birds evolved directly from the dinosaurian ancestors? Because they still carry the dinosaur genetic heritage? Because they are in fact a specialised group of living maniraptoran theropods? I've heard some people say ignorant things like "birds can not be dinosaurs, because they are so different, mostly very small and there is no way that such an agile warmblooded insulated animal could be a descendant of something like T. rex".Thank you for your thoughts! Tom--Thomas R. Holtz, Jr.
Email: tholtz@umd.edu Phone: 301-405-4084
Principal Lecturer, Vertebrate PaleontologyOffice: Geology 4106, 8000 Regents Dr., College Park MD 20742
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/Phone: 301-405-6965
Fax: 301-314-9661
Faculty Director, Science & Global Change Program, College Park ScholarsOffice: Centreville 1216, 4243 Valley Dr., College Park MD 20742
http://www.geol.umd.edu/sgc
Fax: 301-314-9843
Mailing Address: Thomas R. Holtz, Jr.
Department of Geology
Building 237, Room 11178000 Regents Drive
University of Maryland
College Park, MD 20742-4211 USA