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:
“Self-interest is but the survival of the animal in us. Humanity only begins for man with self-surrender.”
—Henri-Frédéric Amiel (1821–1881)
“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)
“There is no mystery in the luminous lines
Of that high, animal face
The smile, sad, humouring and equal
Blesses without obliging
Loves without condescension;”
—Denis Devlin (1908–1959)