Animal Kingdom

This chordata cladogram shows the evolution of hagfishes into mammals. It starts with the Hagfish, which has the Skull trait, and evolves into Amphibians with the Four Legs trait. That amphibian evolved into lizards (or reptiles) in the Amniota and Diapsids group and birds with the Thecodonts group. Eventually we reach mammals with many, many traits carried over from the other groups of animals.