endoderm, the innermost of the three germ layers, or masses of cells (lying within ectoderm and mesoderm), which appears early in the development of an animal embryo. ... The term endoderm is sometimes used to refer to the gastrodermis, the simple tissue that lines the digestive cavity of cnidarians and ctenophores.
the outermost of the three primary germ layers of an embryo that is the source of various tissues and structures (such as the epidermis, the nervous system, and the eyes and ears) b : a tissue (such as neural tissue) derived from this germ layer.
The mesoderm is a germ layer that arises during gastrulation, and is present between the ectoderm, which will turn into skin and central nervous system cells, and the endoderm, which will produce the gut and the lungs.
The key difference between diploblastic and triploblastic animals is that diploblastic animals produce two germ layers excluding mesoderm and triploblastic animals produce all three germ layers.
Diploblastic: Diploblastic animals are not complex. Triploblastic: Triploblastic animals are much complex than diploblastic animals. Diploblastic: Jellyfish, comb jellies, corals and sea anemones are examples. Triploblastic: Molluscs, worms, arthropods, echinodermata and vertebrates are examples.
