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 we reflect upon the cruelties daily practised upon such of the animal creation as are given us for food, or which we ensnare for our diversion, we shall be obliged to own that there is more of the savage in human nature than we are aware of.”
—Samuel Richardson (1689–1761)
“The animal is one with its life activity. It does not distinguish the activity from itself. It is its activity. But man makes his life activity itself an object of his will and consciousness. He has a conscious life activity. It is not a determination with which he is completely identified.”
—Karl Marx (1818–1883)
“Woman is a vulgar animal from whom man has created an excessively beautiful ideal.”
—Gustave Flaubert (1821–1880)