Animal

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Definition

The term animal is used to refer to any living organism that falls in the animal kingdom, one of the kingdoms in the six-kingdom system of classification of species (the other kingdoms are plants, bacteria, archaea, fungi and protists). The following attributes collectively separate animals from other living organisms:

Attribute Value for animals Other kingdoms that share (or may share) this attribute value Kingdoms that don't share this attribute value
Cell type eukaryotic cell plants, fungi, protists bacteria, archaea
Cell type does not have a cell wall some protists (specifically, protozoa) plants, fungi, bacteria, archaea
Cellularity of organism multicellular organism plants, fungi protists, bacteria, archaea
Mode of nutrition heterotrophic organism some plants, some protists most plants (including algae), fungi
Nature of birth embryos pass through a blastula stage none all other kingdoms

The cells of animals are called animal cells. These differ in many important respects from the cells of organisms in other kingdoms.