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).
Read more about Species.
Famous quotes containing the word species:
“Any reading not of a vicious species must be a good substitute for the amusements too apt to fill up the leisure of the labouring classes.”
—James Madison (1751–1836)
“The principle of avoiding the unnecessary expenditure of energy has enabled the species to survive in a world full of stimuli; but it prevents the survival of the aristocracy.”
—Rebecca West (1892–1983)
“A man, to be greatly good, must imagine intensely and comprehensively; he must put himself in the place of another and of many others; the pains and pleasures of his species must become his own.”
—Percy Bysshe Shelley (1792–1822)