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:
“Your cravings as a human animal do not become a prayer just because it is God whom you ask to attend to them.”
—Dag Hammarskjöld (1905–1961)
“We say of an animal that it is intelligent, and we say the same thing of a woman; but in neither case is it usually appropriate—clearly for very different reasons.”
—José Bergamín (1895–1983)
“As a particularly dramatic gesture, he throws wide his arms and whacks the side of the barn with the heavy cane he uses to stab at contesting bidders. With more vehemence than grammatical elegance, he calls upon the great god Caveat Emptor to witness with what niggardly stinginess these flinty sons of Scotland make cautious offers for what is beyond any question the finest animal ever beheld.”
—Administration in the State of Arka, U.S. public relief program (1935-1943)