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:
“Many parents worry that they will reinforce a fear by being overly sympathetic. It helps to know that when children are permitted to avoid an animal or an object that frightens them, they tend to overcome a fear sooner than if parents push them to confront it.”
—Cathy Rindner Tempelsman (20th century)
“Nobody can misunderstand a boy like his own mother.... Mothers at present can bring children into the world, but this performance is apt to mark the end of their capacities. They can’t even attend to the elementary animal requirements of their offspring. It is quite surprising how many children survive in spite of their mothers.”
—Norman Douglas (1868–1952)
“Is man no more than this? Consider him well. Thou ow’st the worm no silk, the beast no hide, the sheep no wool, the cat no perfume. Here’s three on’s are sophisticated. Thou art the thing itself; unaccommodated man is no more than such a poor, bare, forked animal as thou art.”
—William Shakespeare (1564–1616)