Tyrannosaurus
by Nate B.
The Tyrannosaurus is a dinosaur, it is a meat-eater, and it has a very long tail. It is very big, about 18 ft. tall, and 50 ft. long from head to tail. It has serrated teeth, so they slice through flesh. Its arms are small, but are stronger than human arms.
The tyrannosaurus evolved from first being a vertebrate (backbone and brain case), to a gnathostome (jaws), then a tetrapod (limbs). Next, it was given the trait of amniotes (watertight eggs), and then it became a sauropsid (pair of openings in the Palate), then a dinosaur (hole in the hip socket). It was then a saurischian (grasping hand), and then it got 3-toed feet, or a theropod.
The tyrannosaurus is most closely related to the struthiomimus, the deinonychus, the archaeopteryx, and the seagull, according to our class cladogram. I found this out by looking at the most recent node my animal branched off of, then I looked at which animals also branched off of that node. The most advanced trait they all share is that they are all theropods, dinosaurs with 3-toed feet. I found that out by looking at their most recent common ancestor. The major differences between them and the tyrannosaurus are that they all have longer arms (relative to their size) than the tyrannosaurus.
Last updated April 7, 2007.