A cladogram draws relationships based on phylogeny
(shared ancestry) instead of morphology.
A clade contains all the organisms descended from a common ancestor,
and share a character.
For example, all organisms descended from an ancestor that developed
constitute a large clade (ingroup); smaller clades later developed lungs, etc. Note:
- Only animals that have jaws can have hair.
- All animals with hair have jaws.
- Thus, you cannot find an animal with hair but no jaws.