Chapter 26, Problem 1RQ

What are the four membranes associated with amniotic eggs? What is the function of each of these membranes?

Summary Introduction

To determine: The four membranes that are linked with the amniotic eggs.

Introduction: In the late Paleozoic era, the amniotes came into existence and diversified. The clade Amniota includes mammals, reptiles, and birds. The early amniotes were found to be small and lizard like. They diversified in the early Permian period, and this diversification provides many advantages for amniotes.

Explanation of Solution

The derived features of amniotes are amniotic eggs, skeletal features, skin resistant to desiccation, and rib ventilation. The eggs of the amniotes have four extraembryonic membranes. The membranes are the amnion, yolk sac, chorion, and allantois.

Summary Introduction

To determine: The function of the membranes of the amniotic eggs.

Explanation of Solution

Amnion: The amniotic fluid present in the amnion encloses and protects the embryo, cushions the embryo, and also provides an aqueous medium for the embryo to grow.

Allantois: It forms a sac that stores the metabolic wastes.

Chorion: The whole content of the eggs is surrounded by chorion, and it is highly vascularized. The allantois and chorion form a respiratory organ that is efficient in acquiring oxygen and removing carbon dioxide.

Yolk sac: It is essential for nutrient storage.