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:
“In the animal kingdom, the rule is, eat or be eaten; in the human kingdom, define or be defined.”
—Thomas Szasz (b. 1920)
“Come into animal presence.
No man is so guileless as
the serpent. The lonely white
rabbit on the roof is a star
twitching its ears at the rain.”
—Denise Levertov (b. 1923)
“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)