What is an amniotic egg and why is it important?

What is an amniotic egg and why is it important?

The amniotic egg is the key characteristic of amniotes. In amniotes that lay eggs, the shell of the egg provides protection for the developing embryo while being permeable enough to allow for the exchange of carbon dioxide and oxygen.

Can amniotic eggs be laid in water?

Thanks to this, amniotes lay eggs on land or retain them within the mother, unlike anamniotes (fishes and amphibians), which typically lay eggs in water.

Do insects have amniotic eggs?

Only with the evolution of the amniotic egg, an egg with a membrane around it such as those laid by birds and reptiles, did vertebrates genuinely become independent of water. Similarly, in insects it is an innovation in the egg that has made them so successful on the land.

How does the amniotic egg allow for a truly terrestrial existence?

The amniotic egg allowed tetrapods to become completely terrestrial. In an amniotic egg, a membrane called the amnion surrounds the embryo and creates a fluid-filled cavity in which it develops. The amnion keeps the embryo from drying out, so it’s critical to living on land.

Why is the amniotic egg considered a self contained pond?

During the Carboniferous, however, one group of tetrapods evolved an adaptation that allowed them to break free of the pond: the amniotic egg. Instead of being a “naked” egg laid in a pond or stream, the amniotic egg had: A shell to prevent desiccation. A self-contained “pond” (the amnion) in which the embryo grew.

Are dinosaurs Amniotes?


Are cats an Amniote?

Amniotes such as mammals, dinosaurs, and birds evolved a more upright stance. The cat in Figure 1.2 has straighter limbs than the lizard. Its legs are underneath its body and hold it far away from the ground.

What are the 6 classes of animals?

The six basic animal groups include amphibians, birds, fish, invertebrates, mammals, and reptiles.