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
Ancestor Ancestor An ancestor is a parent or (recursively) the parent of an antecedent (i.e., a grandparent, great-grandparent, great-great-grandparent, and so forth). "Ancestor" is "any person from whom one is descended. In law the person from whom an estate has been inherited." Two individuals have a genetic relationship if one is the ancestor of the other, or if they share a common ancestor. In evolutionary theory, species which share an evolutionary ancestor are said to be of common descent. However, this concept of ancestry does not apply to some bacteria and other organisms capable of horizontal gene transfer. Some research suggests