What is Species?
{{For|the chemical objects|Chemical species}} [[File:Biological classification L Pengo.svg|right|150px]] A '''species''' is a kind of [[organism]]. It is a basic unit of [[biological classification]], and a formal rank in [[taxonomy]]. Originally, the word was used informally in a rather vague way, but now there are at least 26 different ways it is used.<ref>Wilkins, John 2008. Species concepts in modern literature: summary of 26 species concepts. ''Reports of NCSE'' '''26''' (4). [http://ncse.com/evolution/science/species-concepts-modern-literature] {{Webarchive|url=https://web.archive.org/web/20120609135344/http://ncse.com/evolution/science/species-concepts-modern-literature |date=2012-06-09 }}</ref> All animals or plants that are the same kind belong to the same species. [[Wolf|Wolves]] (''Canis lupus'') are one species. [[Humans]] (''[[Homo sapiens]]'') are another species. Broadly, the idea is that, for example, cats breed with cats and produce more cats. This is the basis for deciding to have a species called ''Felis catus''. However, to give a simple [[definition]] of 'species' is difficult, and many people have tried.<ref>Wilkins, John 2006. Species, kinds and evolution. ''Reports of the National Center for Science Education''. '''26''' (4), 36–45. [http://ncse.com/rncse/26/4/species-kinds-evolution] {{Webarchive|url=https://web.archive.org/web/20120122081717/http://ncse.com/rncse/26/4/species-kinds-evolution |date=2012-01-22 }}</ref> Species is a word for a particular kind of living thing, for example, a [[jackdaw]]. Jackdaws and [[raven]]s are similar, so they are together in a larger group ([[taxon]]) called a [[genus]], in this case ''[[Corvus]]''. Then there is a [[family (biology)|family]] (such as the [[Corvidae|crow family]], which includes crows and ravens as well as [[jay]]s and [[magpie]]s). Families are put together into [[order (biology)|orders]] such as the [[songbird]]s, which includes many families of birds. The next group is the [[Class (biology)|class]]; all [[bird]]s are in the same c