Dichotomous Key/Animalia

Animalia Animalia Key to Animalia 1: Single-celled organism. 2: Multi-cellular organism. 1 incomplete Single cell protists Glossary for this page (all links are to Wikipedia articles)Digestive cavity:Radial symmetry: Circular symmetry where cutting planes produces roughly identical piecesBilateral symmetry: Symmetry where only one plane, called the sagittal plane, will divide an organism into roughly mirror image halvesTrochophore: A type of free-swimming ciliated planktonic marine larvaLophophore: A feeding organ consisting of a ring of ciliated tentacles surrounding the mouth.Segmentation: The division of body plans into a series of repetitive segments.Mantle:Symbiosis:Ecydsis:Joint:Notochord: 2 3: Specialized cells absent, though different types of cells may be present. Digestive cavity absent. Muscles, nerves, and organs absent. Parazoa. 4: Specialized cells present. Digestive cavity present. Muscles, nerves, and organs present in some form. True tissues organized into germ layers. Enterozoa. 3: Parazoa Placozoa: Simple tissues present. Porifera: Simple tissues absent. 4: Eumetazoa 5: Hollow body cavity present. Radially symmetric body. Aquatic. Colonial or solitary. Respiration and excretion accomplished by diffusion. 6: Body cavity not hollow. Radially or bilateral body symmetry. Aquatic, terrestrial or both. Mostly solitary. 5 Cnidaria: Cnidocytes present; Medusa and polyp form; Incomplete digestive system. Ctenophora: Sticky prey-capturing colloblast cells present; Medusa form only; Complete digestive system. 6 Chordate: Possesses a notochord, a hollow dorsal nerve cord, pharyngeal slits, or an endostyle, for at least some period of its life cycle. 7: Notochord, a hollow dorsal nerve cord, pharyngeal slits, and an endostyle absent during entire life cycle. 7 Echinoderm: Adults have radial symmetry. Inhabitants of salt water. 8: Adults have bilateral symmetry. Inhabitants of fresh water, salt water, or dry land. 8 Ecdysozoa: Exoskeleton shed during life cycle. 9: Exoskeleton absent, or not shed during life cycle. 9 incomplete Orthonectida, Rhombozoa, Acoelomorpha, Chaetognatha, Hemichordata, Xenoturbellida, Platyzoa, Lophotrochozoa __NOTOC__ fr:Clés dichotomiques/Animalia