This document discusses key anatomical and evolutionary concepts including homology, analogy, homoplasy, apomorphy, plesiomorphy, synapomorphy, and symplesiomorphy. It provides examples of hair being a synapomorphy of therians and an autapomorphy of mammals. Additionally, it notes that the carnassial pair formed from the 4th upper premolar and 1st lower molar is a synapomorphy of cats and dogs that indicates their close relationship.

1. Chapter 2 Anatomical and Evolutionary Concepts

4. Analogy

7. Within this taxon set, hair is a unique character (autapomorphy) of mammals

8. The Carnassial Pair as a synapomorphy of Cats & Dogs The diagram indicates that a particular character state (presence of a carnassial pair formed from the 4th upper premolar and the 1st lower molar) occurs Cats and Dogs. Eutherian insectivores (such as shrews) and marsupials (such as kangaroos) retain the ancestral, unspecialized form of the molariform teeth.