Animal
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.
Read more about Animal: Etymology, Characteristics, Origin and Fossil Record, Model Organisms, History of Classification, Ethics
Famous quotes containing the word animal:
“When a woman drinks it’s as if an animal were drinking, or a child. Alcoholism is scandalous in a woman, and a female alcoholic is rare, a serious matter. It’s a slur on the divine in our nature.”
—Marguerite Duras (b. 1914)
“Not only does every animal live at the expense of some other animal or plant, but the very plants are at war.... The individuals of a species are like the crew of a foundered ship, and none but good swimmers have a chance of reaching the land.”
—Thomas Henry Huxley (1825–95)
“Be a good animal, true to your animal instincts.”
—D.H. (David Herbert)