Reptile Reproduction - Anatomy & Physiology
Introduction
The evolutionary development of reptiles depended primarily on them being able to discard the attachment to a watery or humid environment for survival and breeding perposes. Of the numerous features exibited by reptilia as a group, the most important in an evolutionary context are:
- Almost all reptiles are covered by a protective layer of dry skin with almost no glands. The epidermis is raised to form scales or scutes. This prevents excessive water loss, thus is essential for terrestrial existence.
- They developed a large, yolked egg, allowing the embryo sufficient food reserves to develop fully before hatching. The yolked egg is surrounded by protective extra-embryonic membranes (the amnion and allantois), serving for respiration and the storage of waste. There is also a protective calciferous shell to prevent it from drying out.