The phylum Chordata contains most common animals you are familiar with such as eagles, dogs, foxes, and frogs. While the earth is home to many members of this phylum, earthworms are not a member of Chordata. The most successful phylum on earth is Arthropoda, which contains insects, spiders, and crustaceans. An animal that molts its exoskeleton is called an arthropod. Stem cells are cells that have the potential to become any type of cell; they have not yet received their genetic programming. All members of the animal kingdom are multicellular, heterotrophic, and eukaryotic. A starfish is a bilaterian deuterostome with pentaradial symmetrical adults. Complete the chart by describing what kinds of organs or tissues each type of germ layer becomes: Endoderm becomes the lining of the digestive tract, Mesoderm becomes muscles, bones, and circulatory system, Ectoderm becomes the skin and nervous system.