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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Some articles on species:
... All species have a proboscis which lies in the rhynchocoel when inactive but everts (turns inside-out) to emerge just above the mouth and capture the animal's prey with venom ... A few species with stubby bodies filter feed and have suckers at the front and back ends, with which they attach to a host ... Most nemerteans have various chemoreceptors, and on their heads some species have a number of pigment-cup ocelli, which can detect light but not form an image ...
... Orthopteroid species have a paurometabolous life cycle or incomplete metamorphosis ... The use of sound is generally crucial in courtship, and most species have distinct songs ... The number of moults varies between species growth is also very variable and may take a few weeks to some months depending on food availability and weather conditions ...
... Comprises 100 marine species ... Comprises about 400 species ... Includes seven species, of which six live as commensals in the mantle of large clams and one in that of a freshwater snail ...
... Most nemertean species have just one pair of nerve cords, many species have additional paired cords, and some species also have a dorsal cord ... In some species the cords lie within the skin, but in most they are deeper, inside the muscle layers ... Some species have paired cerebral organs, sacs whose only openings are to the outside ...
... An average of 30% more species inhabit organic farms ... Many weed species attract beneficial insects that improve soil qualities and forage on weed pests ... Species found in organic farms enhance sustainability by reducing human input (e.g ...
More definitions of "species":
- (noun): A specific kind of something.
Example: "A species of molecule"; "a species of villainy"
Famous quotes containing the word species:
“There are acacias, a graceful species amusingly devitalized by sentimentality, this kind drooping its leaves with the grace of a young widow bowed in controllable grief, this one obscuring them with a smooth silver as of placid tears. They please, like the minor French novelists of the eighteenth century, by suggesting a universe in which nothing cuts deep.”
—Rebecca West (18921983)
“If Steam has done nothing else, it has at least added a whole new Species to English Literature ... the bookletsthe little thrilling romances, where the Murder comes at page fifteen, and the Wedding at page fortysurely they are due to Steam?
And when we travel by electricityif I may venture to develop your theorywe shall have leaflets instead of booklets, and the Murder and the Wedding will come on the same page.”
—Lewis Carroll [Charles Lutwidge Dodgson] (18321898)
“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 (17511836)