Dinosaur Walk Museum modern day birds. Troodon: The Troodon, a very small bird-like dinosaur, grew to be up to in length, tall and only weighed up to 130 pounds. Living during the late Cretaceous Period, 75–66 million years ago. Originally thought to be carnivorous, modern evidence shows that it is possible that they were omnivorous or possibly an herbivore. Plesiosaurs: The Plesiosaurs were carnivorous aquatic reptiles. First appearing at the beginning of the Jurassic Period they thrived throughout the Cretaceous Period. They lived during the same time as the dinosaurs but were not dinosaurs, they are considered reptiles. Oviraptor: The Oviraptor, or "Egg
Most recent common ancestor all of the modern population. Due to pedigree collapse, modern individuals may still exhibit clustering, due to vastly different contributions from each of ancestral population . Most recent common ancestor In biology and genealogy, the most recent common ancestor (MRCA, also last common ancestor (LCA), or concestor) of any set of organisms is the most recent individual from which all the organisms are directly descended. The term is also used in reference to the ancestry of groups of genes (haplotypes) rather than organisms. The MRCA of a set of individuals can sometimes be determined by referring to an established pedigree.