Amniotes

Amniotes are a group of vertebrate animals comprising reptiles, birds and mammals. They are characterized by an embryo which is encased in a fluid-filled amniotic sac within the mother's body. This membrane protects them from dehydration, provides a constant temperature environment, and limits the need for mobility and swimming. The amniotic sac is significant because it allows amniotes to reproduce in drier environments and to live on land, traits that distinguish them from other vertebrates such as fish and amphibians. Amniotes are found in a wide range of habitats, from deserts to oceans, and are well adapted for a terrestrial environment. They are found in many different sizes and lifestyles, from large predators to small rodents. Amniotes are essential to global ecosystems, with many species playing an important role in the food chain and providing essential resources such as food, fuel, materials, and medicines.