Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and independently. All animals are also heterotrophs, meaning they must ingest other organisms or their products for sustenance.
Most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago.
Famous quotes containing the word animal:
“... these great improvements of modern times are blessings or curses on us, just in the same ratio as the mental, moral, and religious rule over the animal; or the animal propensities of our nature predominate over the intellectual and moral. The spider elaborates poison from the same flower, in which the bee finds materials out of which she manufactures honey.”
—Harriot K. Hunt (18051875)
“Be a good animal, true to your animal instincts.”
—D.H. (David Herbert)
“Afflicted with existence, each man endures like an animal the consequences which proceed from it. Thus, in a world where everything is detestable, hatred becomes huger than the world and, having transcended its object, cancels itself out.”
—E.M. Cioran (b. 1911)