Changes

A usable definition of the [[word]] "species" and reliable [[methods]] of identifying particular species is [[essential]] for stating and testing [[biological]] [[theories]] and for measuring biodiversity. [[Traditionally]], multiple examples of a proposed species must be [[studied]] for unifying characters before it can be regarded as a species. It is generally difficult to give precise taxonomic rankings to extinct species known only from [[fossils]].

A usable definition of the [[word]] "species" and reliable [[methods]] of identifying particular species is [[essential]] for stating and testing [[biological]] [[theories]] and for measuring biodiversity. [[Traditionally]], multiple examples of a proposed species must be [[studied]] for unifying characters before it can be regarded as a species. It is generally difficult to give precise taxonomic rankings to extinct species known only from [[fossils]].

Some [[biologists]] may see species as [[statistical]] [[phenomena]], as opposed to the [[traditional]] [[idea]], with a species seen as a class of [[organisms]]. In that case, a species is defined as a separately [[evolving]] lineage that forms a single gene pool. Although properties such as [[DNA]]-sequences and morphology are used to help separate closely-related lineages, this definition has fuzzy boundaries.[1] However, the exact definition of the term "species" is still controversial, particularly in [http://en.wikipedia.org/wiki/Prokaryotes prokaryotes],[2] and this is called the species problem.[3] Biologists have proposed a range of more [[precise]] definitions, but the definition used is a [[Practical|pragmatic]] [[choice]] that depends on the particularities of the species concerned.[http://en.wikipedia.org/wiki/Species]

Some [[biologists]] may see species as [[statistical]] [[phenomena]], as opposed to the [[traditional]] [[idea]], with a species seen as a class of [[organisms]]. In that case, a species is defined as a separately [[evolving]] lineage that forms a single gene pool. Although properties such as [[DNA]]-sequences and morphology are used to help separate closely-related lineages, this definition has fuzzy boundaries.[1] However, the exact definition of the term "species" is still controversial, particularly in [http://en.wikipedia.org/wiki/Prokaryotes prokaryotes],[2] and this is called the species problem.[3] Biologists have proposed a range of more precise definitions, but the definition used is a [[Practical|pragmatic]] [[choice]] that depends on the particularities of the species concerned.[http://en.wikipedia.org/wiki/Species]

[[Category: Biology]]

[[Category: Biology]]