Clockwise from top-left: Loligo vulgaris (a mollusk), Chrysaora quinquecirrha (a cnidarian), Aphthona flava (an arthropod), Eunereis longissima (an annelid), and Panthera tigris (a chordate). Scientific classification Domain: Eukaryota (unranked) Opisthokonta Kingdom: Animalia Linnaeus, 1758 Phyla Subregnum Parazoa Porifera (alternatively) Calcarea Silicarea Subregnum Eumetazoa Placozoa Radiata (unranked) Ctenophora Cnidaria Trilobozoa ? Bilateria (unranked) Orthonectida Rhombozoa Acoelomorpha Chaetognatha Superphylum Deuterostomia Chordata Hemichordata Echinodermata Xenoturbellida Vetulicolia ? Superphylum Ecdysozoa Kinorhyncha Loricifera Priapulida Nematoda Nematomorpha Lobopodia ? Onychophora Tardigrada Arthropoda Superphylum Platyzoa Platyhelminthes Gastrotricha Rotifera Acanthocephala Gnathostomulida Micrognathozoa Cycliophora Superphylum Lophotrochozoa Sipuncula Hyolitha ? Nemertea Phoronida Bryozoa Entoprocta Brachiopoda Mollusca Annelida Echiura

Orange elephant ear sponge, Agelas clathrodes, in foreground. Two corals in the background: a sea fan, Iciligorgia schrammi, and a sea rod, Plexaurella nutans. Animals are a major group of organisms, classified as the kingdom Animalia or Metazoa. In general they are multi­cellular, responsive to their environment, and feed by consuming other organisms or parts of them. Their body plan becomes fixed as they develop, usually early on in their development as embryos, although some undergo a process of metamorphosis later on. The word "animal" comes from the Latin word animal, of which animalia is the plural, and is derived from anima, meaning vital breath or soul. In everyday colloquial usage, the word usually refers to non-human animals. The biological definition of the word refers to all members of the Kingdom Animalia. Therefore, when the word "animal" is used in a biological context, humans are included.