The ancestral character is normally inherited from a distant ancestor while the derived character is one that has experienced fresh evolutionary transformation in a group. The derived characters are employed to classify species that share the trait together to signify that a common contemporary ancestor had similar traits.
The sharks share a common character with the rest of the organism in the tree, which is a vertebra. This implies that all animals in the phylogenetic tree are vertebrae. The second trait that is found in all the animals except the shark is a bony skeleton that developed in Phase 2 of the tree. This makes the shark different from the other organisms. At level 3, the specific trait that is shared amongst the rest of animals is four limbs. Therefore, ray-finned fish are separated from the other animals at this stage of growth. At the development stage, 4 the common trait is an amniotic egg that is present in the remaining species. At level 5, the derived character that makes primates, rodents, and rabbits to be distinct is the existence of hair. The crocodiles, dinosaurs, and birds, have one trait, which is two post-orbital fenestrae (University of California Museum of Paleontology, 2011).
In conclusion, transformation in character happens in a period where traits may be acquired or become extinct.