Chapter 32.3, Problem 3CC

Summary Introduction

To evaluate: The claim that worms, humans, and most other triploblasts have a shape analogous to that of a doughnut.

Concept introduction: Animals can be grouped into diploblastic and triploblastic on the basis of number of germ layers possessed by them. Diploblastic animals are those that contain only two germ layers. Cnidarians and a few other groups of animals are diploblastic.

On the other hand, triploblastic are animals that contain three germ layers. The triploblasts consist of a number of animals ranging from flatworms to vertebrates.