animal kingdom

(redirected from Animal kindom)
Also found in: Dictionary, Thesaurus, Encyclopedia.

animal kingdom

A main classification of living organisms that includes all animals.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

animal kingdom

a category of living organisms comprising all animals. The classification of animals into major groups is now generally agreed by most biologists, unlike the situation in the PLANT KINGDOM where there are several alternative systems of classification. The system below places the Protozoa in the animal kingdom, as in the older classical approaches to the classification, but in more modern approaches only the Parazoa and Metazoa are considered to be animals and the Protozoa are placed in several groupings of kingdom-equivalent status. See CLASSIFICATION.

Protozoa - single-celled animals

Parazoa - sessile, aquatic, porous animals

Porifera - sponges

Metazoa -

Coelenterata - two-layered, sac-like animals possessing a MESOGLOEA and stinging cells

Hydrozoa - hydra, colonial hydroids, siphonophores

Scyphozoa - jellyfish

Anthozoa - corals Phylum

- flattened, wormlike animals

Turbellaria - flatworms

Trematoda - flukes

Cestoda - tapeworms

Nematoda - roundworms

Nemertea - bootlace worms

Annelida - segmented worms

Polychaeta - paddle worms

Oligochaeta - earthworms

Hirudinea - leeches

Mollusca - soft-bodied animals often possessing a shell

Gasteropoda - snails

Lamellibranchiata - bivalves

Cephalopoda - squids and octopus

Arthropoda - jointed-limbed animals with an exoskeleton

Crustacea - water fleas, barnacles, crabs, etc.

Myriapoda - centipedes, millipedes

Arachnida - mites, ticks, scorpions, spiders

Insecta - insects

Echinodermata - spiny animals with a penta-radiate symmetry

Asteroidea - starfish

Ophiuroidea - brittle stars

Echinoidea - sea urchins

Holothuroidea - sea cucumbers

Crinoidia - feather stars and sea lilies

Chordata - animals possessing a notochord at some stage during their development

Protochordata - sea squirts, Amphioxus


Agnatha - jawless fishes, e.g. lamprey

Chondrichythyes - sharks

Choanichthyes - coelacanth, etc.

Actinopterygii - bony fish

Amphibia - salamanders, frogs, toads

Reptilia - reptiles

Aves - birds

Class Mammalia - mammals

Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005