OBJECTIVES OF THE LABORATORY
1. To examine the basic body plan, and the feeding, reproductive, respiratory and circulatory systems of the Phylum Chordata.
INTRODUCTION
Chordates are defined by the presence of three major features: one is the dorsal, hollow nerve cord, which in mammals becomes the brain and spinal cord. Another major characteristic is the notochord, a cartilaginous rod that develops dorsal to the primitive gut in the early embryo. In the lower chordates, the notochord persists throughout life; whereas, in the vertebrates, it is surrounded and later persists as the soft centre of the intervertebral discs The third chordate characteristic is the presence, during some stage in the life cycle, of gill slits in the pharynx or throat. We will examine two animals belonging to different classes within this phylum: the perch (class Osteichthyes) and the rat (class Mammalia).