Species
In biology, a species (plural: species) is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, the difficulty of defining species is known as the species problem. Differing measures are often used, such as similarity of DNA, morphology, or ecological niche. Presence of specific locally adapted traits may further subdivide species into "infraspecific taxa" such as subspecies (and in botany other taxa are used, such as varieties, subvarieties, and formae).
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Famous quotes containing the word species:
“The further our civilization advances upon its present lines so much the cheaper sort of thing does “fame” become, especially of the literary sort. This species of “fame” a waggish acquaintance says can be manufactured to order, and sometimes is so manufactured.”
—Herman Melville (1819–1891)
“Let us guard against saying that death is opposed to life. The living is merely a species of the dead, and a very rare species.”
—Friedrich Nietzsche (1844–1900)
“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)