Subspecies
The subspecies or subspecies (abbreviated subsp., Or ssp. ) Is in the biological classification, the taxonomic rank directly below the Art In botany are under her variety and shape. In zoology and bacteriology, the subspecies is the lowest rank. It provides taxonomically represent a secondary category, ie is only used when needed.
Definition
Ernst Mayr defined the subspecies in 1969 in Principles of Systematic Zoology as:
" A subspecies is the summary of phenotypically similar populations of a species, inhabiting a geographic subdivision of the area of the species and taxonomically different from other populations of the species. "
Like all other hierarchical ranks of biological systematics except the type (genus, tribe, kingdom, etc.) than the subspecies rank can not be objectified, but is based on convention.
" In view of the many cases of incorrect use of the term must be emphasized that the subspecies represents a fundamentally different from the type category. There is no criterion for the definition of the category subspecies, that would not artificial. The subspecies is not evolution unit - unless it also represents a geographical isolate dar. "
This does not mean that actually observable or definable subspecies would be no real biological units. However, it can not be objectified and between different processors often disputed whether the objective differences for the definition of a subspecies are sufficient. Many editors prefer to take this to only as "local population ".
Application
In zoology and botany groups of related individuals are referred to as sub-species, if the individuals of a group on the one hand obvious to those of the other groups are pairing capable (ie, an important criterion for the delimitation of species not comply with), but on the other hand, as a group ( as kin ) are delineated sufficiently clear to other groups ( clans ) and also live in a certain geographic subregion of the distribution area of the species. Systematists thus lead subspecies is primarily used in particularly rich in forms species, with a really sharp delineation of these infraspecific taxa not always succeed. Recent subspecies are always spread varies spatially or temporally ( vicariously ), but often not completely isolated. At the crossroads, they usually form fertile hybrids (abbreviated nothosubsp or NSSP, Greek nothos = false, untrue, illegitimate. . ).
In the overlapping area of their distribution areas ( Hybridisationszone ) are subspecies usually interconnected by so-called transitional populations. The reason for such fluid transitions is that there are no reproductive barriers between species with Hybridisationszonen. But if a population is separated from its parent population, then this may result in a constantly ongoing process of speciation develop a new type, which then acquired isolation mechanisms to the other populations. Such smooth transitions there can be many different shapes. Today, not continuous over the entire population varying characteristics ( klinale variation ) are used to delineate species usually used and this population thus divided completely arbitrary, but are distinct differences in characteristics used that have developed in the course of a temporary geographical isolation.
In biological nomenclature, the subspecies is a three-part name, the trinomen marked. So the trinomen Panthera leo is massaicus example for a subspecies of the lion. In botany, the abbreviation is additionally subsp. insert (eg Lilium pardalinum subsp. pitkinense ), the use of frequently to be found abbreviation " ssp. " is now discouraged by the ICBN.
History
The subspecies in botany
Carl Linnaeus unrelated taxonomic concept of subspecies, below the way it was with him only the variety. It included any deviation from the ideal type of the way in his work, he marked it with a leading Greek letters. In his work Philosophia Botanica 1751 he defined the variety as an environmentally -related, reversible and non- heritable modification of the phenotype: " The variety is a plant that is changed from an accidental cause: climate, soil, heat, winds, etc., which therefore strikes back again on the amended soil. " This definition also turned Linnaeus himself not consistent at.
Similar to the varieties found in him already subspecies, although he has not yet used the term. As with the variety he introduced following the Arteintrag subentries with a leading Greek letters on these items but still added to give them their own names, such as in Primula veris: α officinalis L. elatior L. β and γ acaulis L. In this particular case, he pointed out the special position of the groups nor by a note which retains the stability of features and the importance of geographic distribution: " Although these varieties are thus constant, I distinguish not quite an African from a European Art " So different Linnaeus content and form, although between varieties and subspecies in the modern sense, but they are all subsumed under the term varietas.
It was only his student Jakob Friedrich Ehrhart separated Linnaeus approach also linguistically. In 1780 he wrote in his attempt at a list of around Hanover wild plants in advance that he had the "apparent species, species or subspecies half " led with the introduced Linnaeus name and I will rewrite more. At the same time he explicitly distinguishes this from the variety from by indicating that he would just as soon deal with the " varieties or varieties ", but disregard them here. In 1784 he then gives the first definition of the subspecies:
" Halberds, apparent species, sub-species. [ ... ] There are, in a word Varietates Constantes, or an agent between species and varieties. They differ from species that it is disposed of in small and less significant circumstances of each other and game species, they differ much, that they propagate through the resistant seeds, and again their peers testify. "
The key to the breakthrough of the concept in botany but was its use by Christian Hendrik Persoon 1805. Conceptually, he led the subspecies concept further, had already represented Linnaeus, but separated for the first time both conceptually as nomenclatural between subspecies and variety. Unlike Ehrhart he related also no alternative term such as " the Captain ", so that only Persoons concept was clear. In Germany and the coined by German botany countries, the term subspecies / Subspecies initially sat through, but not in the French-speaking world, there was talk preferred by the "form". Other terms have been created ( "Race ", " permanent modification" ), but none prevailed and term and rank fell temporarily out of use.
This was reinforced by the general softening of taxonomic ranks in the wake of the publication of Charles Darwin's " The Origin of Species " in 1859 Darwin wrote "No one can draw a clear dividing line between individual differences and slight varieties.; or between clearly marked varieties and subspecies and species. "The success of this book led to a relative step back in taxonomic terms, since by its flowing and artificial concept of species previously -won distinctions between the ranks were lost again.
The subspecies in zoology
The Danish ornithologist Frederick Faber 1825 formulated a concept of geography and morphology of the species as the variety of different equally, but in itself but constant clans, it failed to introduce a term for it. Faber saw the spatial center of a species as their " Typusort " but recognized by this remote by migration, morphologically diverse taxa as in constantly in their characteristics, making the Linnaean not varietas the style but not yet at hand, since all representatives still belonged to a reproductive community.
The German entomologist and botanist Eugen Johann Christoph Esper then led the first zoologist in his 1781 dissertation, published De varietatibus specierum in Naturæ productis the concept of subspecies as necessary separate rank between a subspecies and variety. He distinguished between "accidental varieties ", which he called Varietates, and "essential varieties ," which he described as a subspecies.
Only the ornithologist, Hermann Schlegel created in 1844 with the Conspecies a subspecies of the appropriate rank, defined and carried a ternary nomenclature one, so another part of the name in addition to the type clearly designating binomials.
The subspecies in anthropology
The delineation of subspecies and varieties is often very difficult and not objective. Require Expanding borders "artificial" boundaries, the clearly visible differences of human phenotypes different continents easily lead into temptation to accept different races or subspecies But even between " blacks" and " whites. " the transitions are fluid, so that mankind can be arbitrarily divided into an indefinite number of geographical populations only.
Genetically considered (genotype ) all humans are 99.9% alike. Although in some populations (eg, Australian Aborigines, the Negritos or San ) exists such a long physical isolation, that here would be given to the criteria for subspecies of zoological point of view, a further breakdown of the species Homo sapiens is analogous to the proscribed race - term avoided. Only extinct representative of modern man, such as the Neanderthals or the Denisova human are considered still partly as a subspecies. Even supposing that the implication of the human genetic research by Svante Pääbo confirm that a slight mixture of modern humans has taken place with Neanderthals, Neanderthals as a subspecies (Homo sapiens neanderthalensis ) could be expelled.
Spatial isolation as a prerequisite for the formation of subspecies prevailed for the people groups of prehistoric times over very long periods of time because humanity at that time consisted of only a few hundred thousand individuals. During this time some new physical traits arose due to the evolutionary adaptations to particular environmental conditions (eg Mongolian fold, different skin colors, lactose intolerance, dwarfism, Fettsteiß, peppercorn hair and some more). Throughout history, the number of people but it grew exponentially, so that the different populations met and mingled again in numerous ways. This is the reason that the genetic differences between individuals of a population are often significantly larger today than between different populations. In particular, the human geneticist Cavalli - Sforza has this fact extensively researched and documented in humans.
Geographical races
Over time, the abundance of the collected and described creatures increased enormously, which meant that more and more intraspecific differences came to light. The variations themselves, their bandwidth, and the question of the causes aroused the interest of researchers. From then collected not only individual carefully selected specimens that seemed perhaps especially gorgeous, vivid or typical, but whole series to the variety of contexts, and compared them with each other. It turned out that the collected pieces were particularly similar to each other when they come from the same place or from the same region, whereas the difference was particularly pronounced when series widely separated localities were compared. In their extensive travels in the 18th and 19th centuries, the researchers found ever wider populations, resulting in all sorts of details differed from what was thought to date to the type of the species. When it was recognized that geographical variations are something completely different than what was previously referred to as races or varieties, they tried to bring the terminology to express. Limited to certain sub- areas of the total area of the species populations with different dimension values , phenotypic groups or morphs, which could be assigned to specific geographic locations, were in contrast to the previously designated as varieties or breeds taxa as " geographical races ", " geographical varieties " and later referred to as " subspecies ".
Until about the end of the 19th century was the subspecies as a taxonomic unit similar to the morphospecies, but of lower taxonomic rank, she was treated as before completely typologically. Many authors use the terms subspecies and subspecies similar to non-critical and non-specific as previously breed or variety and designated so that any distinguishable units that were less diverse than species. They neglected the already worked out by Pallas and Esper essential component of the new notion, which at least partly geographical isolation. Subspecies are allopatric and allochron.