Fishes: Aphyosemion Sjoestedti

Sunday, 22 July 2012

Aphyosemion Sjoestedti

Species that are believed to have the same ancestors are grouped together, and this group is called a genus. A species will be placed in only one genus (although taxonomic opinion might change). Similarity is best checked by the similarity of their DNA,[dubious – discuss] but for practical reasons, other properties are used. All species are given a two-part name, a "binomial name". The first part of a binomial name is the generic name, the genus of the species. The second part is either called the specific name (a term used only in zoology) or the specific epithet (the term used in botany, which can also be used in zoology). For example, Boa constrictor is one of four species of the Boa genus. The first part of the name is capitalized, and the second part has a lower case. The binomial name is written in italics.A usable definition of the word "species" and reliable methods of identifying particular species are essential for stating and testing biological theories and for measuring biodiversity, though other taxonomic levels such as families may be considered in broad-scale studies.Extinct species known only from fossils are generally difficult to assign precise taxonomic rankings, which is why higher taxonomic levels such as families are often used for fossil-based studies.