∞ generated and posted on 2016.11.06 ∞

Reptiles and their descendants, so named for their characteristic shelled egg.

In addition to amniotic egg, the amniotes possess a number of adaptations to life within a desiccating, terrestrial environment, such as keratinized skin and internal fertilization.

The chicken egg is an amniotic egg and chickens are amniotes. The eggs produced by the monotremes such as the duckbilled platypus is an amniotic egg (and, indeed, an egg that is quite reptile like).

Various viviparous reptiles as well as most mammals do not lay their eggs but instead giving birth to live young.

The amniotic egg contains numerous membranes which play roles in nutrient and waste exchange as well as the all-important gas exchange since these eggs have to balance the acquisition of oxygen and elimination of carbon dioxide without losing too much water, a problem for terrestrial organisms in general including plants.