Chapter 35, Problem 9TY

Summary Introduction

Introduction:

The gnathostomes are the subgroup of vertebrates and are also called jawed vertebrates. The gills present in their ancestors are thought to have evolved into jaws. The earlier teeth were made up of placoid scales and had no connection with bones. Therefore, it could not be repaired or regrown but later, the jaws were connected to the teeth and complex morphology developed between the two.