Chapter 32.3, Problem 3C

Summary Introduction

To explain: The relationship between the human jaws and the pharyngeal slits of early chordates.

Concept introduction: Chordates are the deuterostomes. They are coelomates with bilateral symmetrical body structure. Chordates are divided into three clades, namely urochordates, cephalochordates, and vertebrates. There are four shared derived characters that differentiate the chordates from other groups of organisms. These characters are evolved from other animal clades in connection with their locomotion and obtaining food, postanal tail, endostyle, tubular nerve cord, and notochord.