Chapter 37, Problem 14STP

Summary Introduction

To write:

The adaptations that are acquired by the respiratory system of most of the reptiles for life on land.

Introduction: 

Reptiles are creeping vertebrates bearing epidermal scales. They are mostly found in warmer regions. Their skin is dry, rough, and without glands. They are terrestrial as well as aquatic and both the forms respire through the lungs only.

Explanation of Solution

Reptiles do not respire through gills, they have two lungs (except snakes that have one lung). Respiration takes place through the lungs. Ribs help them to expand and contract the body cavity, making the lung respiration more efficient than in amphibians. They have a heart consisting of two auricles and a partially divided ventricle (except for crocodiles that have a four-chambered heart). The amount of dissolved oxygen in water is comparatively less than the atmospheric oxygen. As the reptiles breathe only through lungs, it makes them diffuse more oxygen through their lungs. Even the aquatic reptiles, such as crocodiles, need to come on the surface of the water to breathe. 

Conclusion

The respiratory system of most reptiles is adapted for life on land as unlike amphibians they respire only through their lungs. Lungs help them to diffuse more amount of oxygen from the atmosphere.