Chapter 26, Problem 26.3CR

Summary Introduction

To explain: The logic that phylogeny uses shared derived characters for the establishment of an evolutionary relationship.

Concept introduction:

The construction of a phylogenetic tree is based on the shared characters among organisms. A shared ancestral character is one that has originated in an ancestor of the group. The character is shared by all members of the group descending from it. A group of species constitutes a clade that shares a common character. This character is unique to that clade. So, different characters will emerge during evolution and will form a new clade and character will pass to their descendant. Shared derived characters are features that have not originated in ancestor but present in their descendants.