Dinosaurs and Birds
Are birds really dinosaurs or are they simply related? That is a question that has gained new life in recent years due to the overwhelming facts the are pouring in from newly found fossils and studies from fossils that have been found in the past. Two groups have formed in the study of this question: those who believe birds are a direct result of dinosaurs and those who feel dinosaurs and birds must have had a common ancestor. Determining which view is correct is a matter of opinion based on fact. The main problem involves the use of cladistics or phylogenetic systematics to group organisms according to characteristics they share. When one looks at dinosaur fossils, he or she may feel that certain characteristics are used for something entirely different than someone else who has looked at the same fossil.
One cannot talk about dinosaur and bird lineage without mentioning Archaeopteryx. Most paleontologists agree that Archaeopteryx was the first bird. Archaeopteryx thus represents what paleontologists would call a “transitional form” between two major groups of animals, the reptiles (dinosaurs) and birds. The main difference between the theropods and Archaeopteryx were the long arms of the Archaeopteryx, adapted as wings, the feathers, and the presence of a wishbone that the theropods did not have. All of these features tie it to birds and its other characteristics tie it to theropods.
Just as most dinosaurs are believed to be wild and mean, most are. Unlike the wild and ferocious Tyrannosaurus Rex, the Velociraptor, is a smaller, agile dinosaur. The Brontosaurus can be found with the bigger, more gentle dinosaurs. The Tyrannosaurus Rex, Velociraptor, and Brontosaurus differ greatly in their body structure, diet, and discovery.
The Tyrannosaurus Rex was a very large dinosaur. Measuring 50 feet long, the Tyrannosaurus stood over 20 feet tall. The head of the Tyrannosaurus was five feet long and filled with large teeth...