Diploblasty is a condition of the blastula in which there are two primary germ layers: the ectoderm and endoderm.
The ectoderm, on the other hand, gives rise to the epidermis, the nervous tissue, and if present, nephridia.
Simpler animals, such as sea sponges, have one germ layer and lack true tissue organization.
All the more complex animals (from flat worms to humans) are triploblastic with three germ layers (a mesoderm as well as ectoderm and endoderm).
Groups of diploblastic animals alive today include jellyfish, corals, sea anemones and comb jellies.