What are species?

  • (noun): (biology) taxonomic group whose members can interbreed.
    See also — Additional definitions below


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.

Some articles on species:

Organic Farming - Externalities - Biodiversity
... Nearly all non-crop, naturally occurring species observed in comparative farm land practice studies show a preference for organic farming both by abundance and diversity ... An average of 30% more species inhabit organic farms ... Many weed species attract beneficial insects that improve soil qualities and forage on weed pests ...
Nemertea - Taxonomy
... 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 ...
Nemertea - Description - Nervous System and Senses
... 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 ...
Orthoptera - Life Cycle
... Orthopteroid species have a paurometabolous life cycle or incomplete metamorphosis ... 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 ...
... 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 ... 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 ...

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:

    Can it then be doubted, but that God, who is infinitely fine Spirit, and withal intelligent, can make and change all species and kind of body as he pleaseth? But I dare not say, that this is the way by which God Almighty worketh, because it is past my apprehension: yet it serves very well to demonstrate, that the omnipotence of God implieth no contradiction.
    Thomas Hobbes (1579–1688)

    If there is a species which is more maltreated than children, then it must be their toys, which they handle in an incredibly off-hand manner.... Toys are thus the end point in that long chain in which all the conditions of despotic high-handedness are in play which enchain beings one to another, from one species to another—cruel divinities to their sacrificial victims, from masters to slaves, from adults to children, and from children to their objects.
    Jean Baudrillard (b. 1929)

    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)