From left to right starting top-left: an Australian Green Tree Frog, Tawny Owl, Siberian Tiger, European garden spider, White-lipped snail, Green Sea Turtle, Solitary bee, Asian arowana, Barbary Macaque, Sawfish and a Marbled White butterfly. Scientific classification Domain: Eukaryota (unranked) Opisthokonta Kingdom: Animalia Linnaeus, 1758 Phyla Subkingdom Parazoa Porifera Subkingdom Eumetazoa Placozoa Radiata (unranked) Ctenophora Cnidaria 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 multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. 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 in their life. Most animals are motile - they can move spontaneously and independently. Animals are heterotrophs - they are dependent on other organisms (e.g. plants) for sustenance. Most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago.