Misplaced Pages

#459540

89-478: The sable ( Martes zibellina ) is a species of marten , a small omnivorous mammal primarily inhabiting the forest environments of Russia , from the Ural Mountains throughout Siberia , and northern Mongolia . Its habitat also borders eastern Kazakhstan , China , North Korea and Hokkaido , Japan . The name "sable" originates from Slavic languages and entered Western European languages through

178-423: A mutation–selection balance . It is predicted that a viral quasispecies at a low but evolutionarily neutral and highly connected (that is, flat) region in the fitness landscape will outcompete a quasispecies located at a higher but narrower fitness peak in which the surrounding mutants are unfit, "the quasispecies effect" or the "survival of the flattest". There is no suggestion that a viral quasispecies resembles

267-405: A ring species . Also, among organisms that reproduce only asexually , the concept of a reproductive species breaks down, and each clone is potentially a microspecies. Although none of these are entirely satisfactory definitions, and while the concept of species may not be a perfect model of life, it is still a useful tool to scientists and conservationists for studying life on Earth, regardless of

356-400: A "classical" method of determining species, such as with Linnaeus, early in evolutionary theory. However, different phenotypes are not necessarily different species (e.g. a four-winged Drosophila born to a two-winged mother is not a different species). Species named in this manner are called morphospecies . In the 1970s, Robert R. Sokal , Theodore J. Crovello and Peter Sneath proposed

445-424: A 'smallest clade' idea" (a phylogenetic species concept). Mishler and Wilkins and others concur with this approach, even though this would raise difficulties in biological nomenclature. Wilkins cited the ichthyologist Charles Tate Regan 's early 20th century remark that "a species is whatever a suitably qualified biologist chooses to call a species". Wilkins noted that the philosopher Philip Kitcher called this

534-428: A connected series of neighbouring populations, each of which can sexually interbreed with adjacent related populations, but for which there exist at least two "end" populations in the series, which are too distantly related to interbreed, though there is a potential gene flow between each "linked" population. Such non-breeding, though genetically connected, "end" populations may co-exist in the same region thus closing

623-432: A different species from its ancestors. Viruses have enormous populations, are doubtfully living since they consist of little more than a string of DNA or RNA in a protein coat, and mutate rapidly. All of these factors make conventional species concepts largely inapplicable. A viral quasispecies is a group of genotypes related by similar mutations, competing within a highly mutagenic environment, and hence governed by

712-442: A female kidus successfully breeding with a male pine marten. In Russia, the sable's distribution is largely the result of mass re-introductions involving 19,000 animals between 1940 and 1965. Their range extends northward to the tree line, and extends south to 55–60° latitude in western Siberia, and 42° in the mountainous areas of eastern Asia. Their western distribution encompasses the Ural Mountains , where they are sympatric with

801-508: A genetic boundary suitable for defining a species concept is present. DNA barcoding has been proposed as a way to distinguish species suitable even for non-specialists to use. One of the barcodes is a region of mitochondrial DNA within the gene for cytochrome c oxidase . A database, Barcode of Life Data System , contains DNA barcode sequences from over 190,000 species. However, scientists such as Rob DeSalle have expressed concern that classical taxonomy and DNA barcoding, which they consider

890-498: A highly valued item in the fur trade since the early Middle Ages , and is generally considered to have the most beautiful and richly tinted pelt among martens. Sable fur is unique because it retains its smoothness in every direction it is stroked. The fur of other animals feels rough stroked against the grain. A wealthy 17th-century Russian diplomat once described the sable as "A beast that the Ancient Greeks and Romans called

979-492: A misnomer, need to be reconciled, as they delimit species differently. Genetic introgression mediated by endosymbionts and other vectors can further make barcodes ineffective in the identification of species. A phylogenetic or cladistic species is "the smallest aggregation of populations (sexual) or lineages (asexual) diagnosable by a unique combination of character states in comparable individuals (semaphoronts)". The empirical basis – observed character states – provides

SECTION 10

#1732765005460

1068-449: A particular species, including which genus (and higher taxa) it is placed in, is a hypothesis about the evolutionary relationships and distinguishability of that group of organisms. As further information comes to hand, the hypothesis may be corroborated or refuted. Sometimes, especially in the past when communication was more difficult, taxonomists working in isolation have given two distinct names to individual organisms later identified as

1157-502: A practical one. Shortly after, when the young Shigi Qutuqu was found wandering a destroyed Tatar camp, he was recognised to be of noble descent because of his sable-lined silk jerkin . According to Atkinson's Travels in Asiatic Russia , Barguzin , on Lake Baikal , was famed for its sables. The fur of this population is a deep jet black with white tipped hair. Eighty to ninety dollars were sometimes demanded by hunters for

1246-400: A short way of saying that something applies to many species within a genus, but not to all. If scientists mean that something applies to all species within a genus, they use the genus name without the specific name or epithet. The names of genera and species are usually printed in italics . However, abbreviations such as "sp." should not be italicised. When a species' identity is not clear,

1335-655: A single skin. In 1916, the first nature reserve in the Russian Empire was created—known as the Barguzin Nature Reserve —precisely to preserve and increase the numbers of Barguzin sable. Sable fur would continue to be the most favoured fur in Russia, until the discovery of sea otters in the Kamchatka peninsula, whose fur was considered even more valuable. Sable furs were coveted by the nobility of

1424-404: A specialist may use "cf." before the epithet to indicate that confirmation is required. The abbreviations "nr." (near) or "aff." (affine) may be used when the identity is unclear but when the species appears to be similar to the species mentioned after. With the rise of online databases, codes have been devised to provide identifiers for species that are already defined, including: The naming of

1513-523: A species as groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups. It has been argued that this definition is a natural consequence of the effect of sexual reproduction on the dynamics of natural selection. Mayr's use of the adjective "potentially" has been a point of debate; some interpretations exclude unusual or artificial matings that occur only in captivity, or that involve animals capable of mating but that do not normally do so in

1602-400: A species as determined by a taxonomist. A typological species is a group of organisms in which individuals conform to certain fixed properties (a type), so that even pre-literate people often recognise the same taxon as do modern taxonomists. The clusters of variations or phenotypes within specimens (such as longer or shorter tails) would differentiate the species. This method was used as

1691-491: A species. All species definitions assume that an organism acquires its genes from one or two parents very like the "daughter" organism, but that is not what happens in HGT. There is strong evidence of HGT between very dissimilar groups of prokaryotes , and at least occasionally between dissimilar groups of eukaryotes , including some crustaceans and echinoderms . The evolutionary biologist James Mallet concludes that there

1780-685: A species. Generally the term includes the unknown element of a distinct act of creation. Many authors have argued that a simple textbook definition, following Mayr's concept, works well for most multi-celled organisms , but breaks down in several situations: Species identification is made difficult by discordance between molecular and morphological investigations; these can be categorised as two types: (i) one morphology, multiple lineages (e.g. morphological convergence , cryptic species ) and (ii) one lineage, multiple morphologies (e.g. phenotypic plasticity , multiple life-cycle stages). In addition, horizontal gene transfer (HGT) makes it difficult to define

1869-528: A taxonomic decision at the discretion of cognizant specialists, is not governed by the Codes of Zoological or Botanical Nomenclature, in contrast to the PhyloCode , and contrary to what is done in several other fields, in which the definitions of technical terms, like geochronological units and geopolitical entities, are explicitly delimited. The nomenclatural codes that guide the naming of species, including

SECTION 20

#1732765005460

1958-601: A thousand, as Russia at the time was unable to enforce the tribute due to wars with Sweden and Poland. The best skins were obtained in Irkutsk and Kamchatka . According to the Secret History of the Mongols , when Genghis Khan married his first wife, Börte Ujin, his mother Hoelun received a coat of sable furs from the girl's parents. This was reportedly a very noble gift, serving not only an aesthetic need but also

2047-517: A traditional biological species. The International Committee on Taxonomy of Viruses has since 1962 developed a universal taxonomic scheme for viruses; this has stabilised viral taxonomy. Most modern textbooks make use of Ernst Mayr 's 1942 definition, known as the Biological Species Concept as a basis for further discussion on the definition of species. It is also called a reproductive or isolation concept. This defines

2136-447: A variation on the morphological species concept, a phenetic species, defined as a set of organisms with a similar phenotype to each other, but a different phenotype from other sets of organisms. It differs from the morphological species concept in including a numerical measure of distance or similarity to cluster entities based on multivariate comparisons of a reasonably large number of phenotypic traits. A mate-recognition species

2225-515: A variety of reasons. Viruses are a special case, driven by a balance of mutation and selection , and can be treated as quasispecies . Biologists and taxonomists have made many attempts to define species, beginning from morphology and moving towards genetics . Early taxonomists such as Linnaeus had no option but to describe what they saw: this was later formalised as the typological or morphological species concept. Ernst Mayr emphasised reproductive isolation, but this, like other species concepts,

2314-463: A very thin layer of hair. Newborn cubs weigh between 25 and 35 grams (0.88 and 1.23 oz) and average 10 to 12 centimetres (3.9 to 4.7 in) in length. They open their eyes between 30 and 36 days, and leave the nest shortly afterwards. At seven weeks, the young are weaned and given regurgitated food. They reach sexual maturity at the age of two years. They have been reported to live for up to twenty two years on fur farms, and up to eighteen years in

2403-438: Is "an entity composed of organisms which maintains its identity from other such entities through time and over space, and which has its own independent evolutionary fate and historical tendencies". This differs from the biological species concept in embodying persistence over time. Wiley and Mayden stated that they see the evolutionary species concept as "identical" to Willi Hennig 's species-as-lineages concept, and asserted that

2492-400: Is a group of sexually reproducing organisms that recognise one another as potential mates. Expanding on this to allow for post-mating isolation, a cohesion species is the most inclusive population of individuals having the potential for phenotypic cohesion through intrinsic cohesion mechanisms; no matter whether populations can hybridise successfully, they are still distinct cohesion species if

2581-458: Is a set of organisms adapted to a particular set of resources, called a niche, in the environment. According to this concept, populations form the discrete phenetic clusters that we recognise as species because the ecological and evolutionary processes controlling how resources are divided up tend to produce those clusters. A genetic species as defined by Robert Baker and Robert Bradley is a set of genetically isolated interbreeding populations. This

2670-414: Is between 8 and 8.7 million. About 14% of these had been described by 2011. All species (except viruses ) are given a two-part name , called a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature , also sometimes in zoological nomenclature ). For example, Boa constrictor

2759-414: Is called speciation . Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book The Origin of Species . Speciation depends on a measure of reproductive isolation , a reduced gene flow. This occurs most easily in allopatric speciation, where populations are separated geographically and can diverge gradually as mutations accumulate. Reproductive isolation

Sable - Misplaced Pages Continue

2848-403: Is described formally, in a publication that assigns it a unique scientific name. The description typically provides means for identifying the new species, which may not be based solely on morphology (see cryptic species ), differentiating it from other previously described and related or confusable species and provides a validly published name (in botany) or an available name (in zoology) when

2937-671: Is further weakened by the existence of microspecies , groups of organisms, including many plants, with very little genetic variability, usually forming species aggregates . For example, the dandelion Taraxacum officinale and the blackberry Rubus fruticosus are aggregates with many microspecies—perhaps 400 in the case of the blackberry and over 200 in the dandelion, complicated by hybridisation , apomixis and polyploidy , making gene flow between populations difficult to determine, and their taxonomy debatable. Species complexes occur in insects such as Heliconius butterflies, vertebrates such as Hypsiboas treefrogs, and fungi such as

3026-726: Is hard or even impossible to test. Later biologists have tried to refine Mayr's definition with the recognition and cohesion concepts, among others. Many of the concepts are quite similar or overlap, so they are not easy to count: the biologist R. L. Mayden recorded about 24 concepts, and the philosopher of science John Wilkins counted 26. Wilkins further grouped the species concepts into seven basic kinds of concepts: (1) agamospecies for asexual organisms (2) biospecies for reproductively isolated sexual organisms (3) ecospecies based on ecological niches (4) evolutionary species based on lineage (5) genetic species based on gene pool (6) morphospecies based on form or phenotype and (7) taxonomic species,

3115-403: Is no easy way to tell whether related geographic or temporal forms belong to the same or different species. Species gaps can be verified only locally and at a point of time. One is forced to admit that Darwin's insight is correct: any local reality or integrity of species is greatly reduced over large geographic ranges and time periods. The botanist Brent Mishler argued that the species concept

3204-581: Is normally active during the day, but on islands like Santa Cruz that are home to the Galapagos hawk , the owl is crepuscular. Apart from the relevance to predation, crepuscular activity in hot regions also may be the most effective way of avoiding heat stress while capitalizing on available light. Crepuscular flight activity is preferred by some animals, such as the walnut twig beetle , due to warmer temperatures, moderate wind speeds, and low barometric pressure. Crepuscular activity can be influenced by

3293-727: Is not absolute, because crepuscular animals may also be active on a bright moonlit night or on a dull day. Some animals casually described as nocturnal are in fact crepuscular. Special classes of crepuscular behaviour include matutinal, or "matinal", animals active only in the dawn, and vespertine, only in the dusk. Those active during both times are said to have a bimodal activity pattern. The various patterns of activity are thought to be mainly antipredator adaptations , though some could equally well be predatory adaptations . Many predators forage most intensively at night, whereas others are active at midday and see best in full sun. The crepuscular habit may both reduce predation pressure, increasing

3382-478: Is not valid, notably because gene flux decreases gradually rather than in discrete steps, which hampers objective delimitation of species. Indeed, complex and unstable patterns of gene flux have been observed in cichlid teleosts of the East African Great Lakes . Wilkins argued that "if we were being true to evolution and the consequent phylogenetic approach to taxa, we should replace it with

3471-400: Is one of the species of the genus Boa , with constrictor being the species' epithet. While the definitions given above may seem adequate at first glance, when looked at more closely they represent problematic species concepts. For example, the boundaries between closely related species become unclear with hybridisation , in a species complex of hundreds of similar microspecies , and in

3560-586: Is similar to Mayr's Biological Species Concept, but stresses genetic rather than reproductive isolation. In the 21st century, a genetic species could be established by comparing DNA sequences. Earlier, other methods were available, such as comparing karyotypes (sets of chromosomes ) and allozymes ( enzyme variants). An evolutionarily significant unit (ESU) or "wildlife species" is a population of organisms considered distinct for purposes of conservation. In palaeontology , with only comparative anatomy (morphology) and histology from fossils as evidence,

3649-401: Is sometimes an important source of genetic variation. Viruses can transfer genes between species. Bacteria can exchange plasmids with bacteria of other species, including some apparently distantly related ones in different phylogenetic domains , making analysis of their relationships difficult, and weakening the concept of a bacterial species. Crepuscular A number of factors affect

Sable - Misplaced Pages Continue

3738-434: Is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity . Other ways of defining species include their karyotype , DNA sequence, morphology , behaviour, or ecological niche . In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes

3827-594: Is threatened by hybridisation, but this can be selected against once a pair of populations have incompatible alleles of the same gene, as described in the Bateson–Dobzhansky–Muller model . A different mechanism, phyletic speciation, involves one lineage gradually changing over time into a new and distinct form (a chronospecies ), without increasing the number of resultant species. Horizontal gene transfer between organisms of different species, either through hybridisation , antigenic shift , or reassortment ,

3916-683: The European pine marten . They are also found on Sakhalin . In Mongolia, sables occur in the Altai Mountains and in the surrounding forests of Lake Hovsgol , the latter being contiguous with the Trans-Baikal boreal forest region from which the most valuable sable pelts come. In China, sables occur in a limited area of the Xinjiang Uygur Autonomous Region . In northeastern China, sables are now limited to

4005-699: The German Zobel , Dutch sabel ; the French zibeline , Spanish cibelina, cebellina , Finnish soopeli , Portuguese zibelina and Medieval Latin zibellina derive from the Italian form ( zibellino ). The English and Medieval Latin word sabellum comes from the Old French sable or saible . The term has become a generic description for some black-furred animal breeds, such as sable cats or rabbits , and for

4094-533: The Golden Fleece ." Russian sables would typically be skinned over the mouth with no incision being made on the body. The feet would be retained, so as to keep as much fur as possible. Byzantine priests would wear sable for their rituals. In England , sable fur was held in great esteem. Henry I was presented with a wreath of black sable by the Bishop of Lincoln, for no less than £100, a considerable sum at

4183-845: The Greater Khingan Range . In eastern Heilongjiang, the persistence of sables is suspected in the Lesser Khingan Range . Sables also occur in Hokkaido and on the Korean peninsula. Because of the variable appearance of the sable in different geographic localities, there has been some debate over the exact number of subspecies that can be clearly identified. Mammal Species of the World recognises seventeen different subspecies, but other recent scholarly sources have identified anything from seven to thirty. Sable fur has been

4272-530: The ICZN for animals and the ICN for plants, do not make rules for defining the boundaries of the species. Research can change the boundaries, also known as circumscription, based on new evidence. Species may then need to be distinguished by the boundary definitions used, and in such cases the names may be qualified with sensu stricto ("in the narrow sense") to denote usage in the exact meaning given by an author such as

4361-562: The Russian Empire , with very few skins ever being found outside the country during that period. Some, however, would be privately obtained by Jewish traders and brought annually to the Leipzig fair. Sometimes, sable hunting was a job given to convicts exiled to Siberia. Imperial Russian fur companies produced 25,000 skins annually, with nearly ninety percent of the produce being exported to France and Germany . The civic robes of

4450-570: The colour black in heraldry . Males measure 38–56 centimetres (15–22 in) in body length, with a tail measuring 9–12 centimetres (3.5–4.7 in), and weigh 880–1,800 grams (1.94–3.97 lb). Females have a body length of 35–51 centimetres (14–20 in), with a tail length of 7.2–11.5 centimetres (2.8–4.5 in). The winter pelage is longer and more luxurious than the summer coat. Different subspecies display geographic variations of fur colour, which ranges from light to dark brown, with individual coloring being lighter ventrally and darker on

4539-399: The fly agaric . Natural hybridisation presents a challenge to the concept of a reproductively isolated species, as fertile hybrids permit gene flow between two populations. For example, the carrion crow Corvus corone and the hooded crow Corvus cornix appear and are classified as separate species, yet they can hybridise where their geographical ranges overlap. A ring species is

SECTION 50

#1732765005460

4628-507: The jaguar ( Panthera onca ) of Latin America or the leopard ( Panthera pardus ) of Africa and Asia. In contrast, the scientific names of species are chosen to be unique and universal (except for some inter-code homonyms ); they are in two parts used together : the genus as in Puma , and the specific epithet as in concolor . A species is given a taxonomic name when a type specimen

4717-401: The lunar cycle due to the change in nocturnal light. This creates changes in animal sleep , reproduction , and foraging behaviours, often becoming less active during periods of low light. Animal patterns of activity sometimes change during migration due to changes in environmental conditions. Mule deer are crepuscular, but they are only active at dusk before and during migration. In

4806-464: The shtreimel ). The so-called kolinsky sable-hair brushes used for watercolour or oil painting are not manufactured from sable hair, but from that of the Siberian weasel . Species A species ( pl. : species) is a population of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring , typically by sexual reproduction . It

4895-614: The spring they are only active at dawn because the snow is at its hardest , so it is easier for the deer to move without sinking in the snow. During migration, some types of swallow are active primarily during daytime hours with some activity during twilight hours. Crepuscular animal activity is affected by human activity , because humans are diurnal. Crepuscular animals are less likely to participate in typical foraging or reproductive behaviors and deal with increased stress and mortality rates when humans are present. Animals may change their usual activity patterns in response to

4984-406: The "cynical species concept", and arguing that far from being cynical, it usefully leads to an empirical taxonomy for any given group, based on taxonomists' experience. Other biologists have gone further and argued that we should abandon species entirely, and refer to the "Least Inclusive Taxonomic Units" (LITUs), a view that would be coherent with current evolutionary theory. The species concept

5073-474: The Lord Mayor and Corporation of London , which were worn on State occasions, were trimmed with sable. As with minks and martens, sables were commonly caught in steel traps. Intensified hunting in Russia in the 19th and early 20th century caused a severe-enough decline in numbers that a five-year ban on hunting was instituted in 1935, followed by a winter-limited licensed hunt. These restrictions together with

5162-405: The abbreviation "sp." in the singular or "spp." (standing for species pluralis , Latin for "multiple species") in the plural in place of the specific name or epithet (e.g. Canis sp.). This commonly occurs when authors are confident that some individuals belong to a particular genus but are not sure to which exact species they belong, as is common in paleontology . Authors may also use "spp." as

5251-570: The amount of hybridisation is insufficient to completely mix their respective gene pools . A further development of the recognition concept is provided by the biosemiotic concept of species. In microbiology , genes can move freely even between distantly related bacteria, possibly extending to the whole bacterial domain. As a rule of thumb, microbiologists have assumed that members of Bacteria or Archaea with 16S ribosomal RNA gene sequences more similar than 97% to each other need to be checked by DNA–DNA hybridisation to decide if they belong to

5340-1104: The back and legs. Japanese sables (known locally as クロテン or kuroten ) in particular are marked with black on their legs and feet. Individuals also display a light patch of fur on their throat which may be gray, white, or pale yellow. The fur is softer and silkier than that of American martens . Sables greatly resemble pine martens in size and appearance, but have more elongated heads, longer ears and proportionately shorter tails. Their skulls are similar to those of pine martens, but larger and more robust with more arched zygomatic arches . Sables inhabit dense forests dominated by spruce , pine , larch , Siberian cedar , and birch in both lowland and mountainous terrain. They defend home territories that may be anything from 4 to 30 square kilometres (1.5 to 11.6 sq mi) in size, depending on local terrain and food availability. However, when resources are scarce they may move considerable distances in search of food, with travel rates of 6 to 12 kilometres (3.7 to 7.5 mi) per day having been recorded. Sables live in burrows near riverbanks and in

5429-474: The biological species concept, "the several versions" of the phylogenetic species concept, and the idea that species are of the same kind as higher taxa are not suitable for biodiversity studies (with the intention of estimating the number of species accurately). They further suggested that the concept works for both asexual and sexually-reproducing species. A version of the concept is Kevin de Queiroz 's "General Lineage Concept of Species". An ecological species

SECTION 60

#1732765005460

5518-505: The biological species concept, a cladistic species does not rely on reproductive isolation – its criteria are independent of processes that are integral in other concepts. Therefore, it applies to asexual lineages. However, it does not always provide clear cut and intuitively satisfying boundaries between taxa, and may require multiple sources of evidence, such as more than one polymorphic locus, to give plausible results. An evolutionary species, suggested by George Gaylord Simpson in 1951,

5607-433: The concept of a chronospecies can be applied. During anagenesis (evolution, not necessarily involving branching), some palaeontologists seek to identify a sequence of species, each one derived from the phyletically extinct one before through continuous, slow and more or less uniform change. In such a time sequence, some palaeontologists assess how much change is required for a morphologically distinct form to be considered

5696-479: The crepuscular populations, and offer better foraging opportunities to predators that increasingly focus their attention on crepuscular prey until a new balance is struck. Such shifting states of balance are often found in ecology. Some predatory species adjust their habits in response to competition from other predators. For example, the subspecies of short-eared owl that lives on the Galápagos Islands

5785-841: The date varies geographically. When courting, sables run, jump and "rumble" like cats . Males dig metre long shallow grooves in the snow, frequently accompanied by urination. Males fight each other violently for females. Females enter estrus in spring. Mating can last as long as eight hours. After insemination , the blastocyst does not implant into the uterine wall of the female. Instead, implantation occurs eight months later ; although gestation lasts 245 to 298 days, embryonic development requires only 25–30 days. Sables birth in tree hollows, where they build nests composed of moss, leaves, and dried grass. Litters number one to seven young, although litters of two or three are most common. Males assist females by defending their territories and providing food. Sables are born with eyes closed and skin covered in

5874-502: The development of sable farms have allowed the species to recolonize much of its former range and attain healthy numbers. The Soviet Union allowed Old Believer communities to continue their traditional way of life on the condition that they hand over all sable skins they produced. The dissolution of the Soviet Union led to an increase of hunting and poaching in the 1990s, in part because wild caught Russian furs are considered

5963-564: The endangered Amazon river dolphin , some species of bats , hamsters , housecats , stray dogs , rabbits , ferrets , rats , jaguars , ocelots , bobcats , servals , strepsirrhines , red pandas , bears , deer , moose , sitatunga , capybaras , chinchillas , the common mouse , skunks , squirrels , foxes , wombats , wallabies , quolls , possums and marsupial gliders , tenrecs , and spotted hyenas . Snakes , lizards , and frogs , especially those in desert environments, may be crepuscular. Crepuscular birds include

6052-435: The evidence to support hypotheses about evolutionarily divergent lineages that have maintained their hereditary integrity through time and space. Molecular markers may be used to determine diagnostic genetic differences in the nuclear or mitochondrial DNA of various species. For example, in a study done on fungi , studying the nucleotide characters using cladistic species produced the most accurate results in recognising

6141-572: The fur trade since the early Middle Ages, and its popularity has driven hunting and conservation efforts. Today, sable fur is often used to decorate clothing items, and the species has no special conservation status according to the IUCN Red List . The name sable appears to be of Slavic origin and entered most Western European languages via the early medieval fur trade. Thus the Russian соболь ( sobol' ) and Polish soból became

6230-481: The ground in order to remove the mucus . Sables also occasionally eat fish, which they catch with their front paws. They hunt primarily by sound and scent, and they have an acute sense of hearing . Sables mark their territory with scent produced in glands on the abdomen. Predators of sable include a number of larger carnivores, such as wolves, foxes, wolverines , tigers , lynxes , eagles and large owls . Mating generally occurs between June and August 15, though

6319-575: The medieval fur trade. Sables are small, omnivorous mammals that inhabit dense forests in regions like Russia, Mongolia, and China. They are known for their luxurious fur, which ranges from light to dark brown and is softer and silkier than that of American martens . Sables resemble pine martens in size and appearance but have more elongated heads, longer ears, and shorter tails. They are skilled climbers and primarily hunt by sound and scent. Mating occurs between June and August, and litters typically have two or three offspring. Sable fur has been highly valued in

6408-430: The most luxurious and demand the highest prices on the international market. Currently, the species has no special conservation status according to the IUCN Red List , though the isolated Japanese subspecies M. zibellina brachyurus is listed as "data-deficient". Because of its great expense, sable fur is typically integrated into various clothes fashions: to decorate collars, sleeves, hems and hats (see, for example

6497-483: The numerous fungi species of all the concepts studied. Versions of the phylogenetic species concept that emphasise monophyly or diagnosability may lead to splitting of existing species, for example in Bovidae , by recognising old subspecies as species, despite the fact that there are no reproductive barriers, and populations may intergrade morphologically. Others have called this approach taxonomic inflation , diluting

6586-593: The paper is accepted for publication. The type material is usually held in a permanent repository, often the research collection of a major museum or university, that allows independent verification and the means to compare specimens. Describers of new species are asked to choose names that, in the words of the International Code of Zoological Nomenclature , are "appropriate, compact, euphonious, memorable, and do not cause offence". Books and articles sometimes intentionally do not identify species fully, using

6675-674: The person who named the species, while the antonym sensu lato ("in the broad sense") denotes a wider usage, for instance including other subspecies. Other abbreviations such as "auct." ("author"), and qualifiers such as "non" ("not") may be used to further clarify the sense in which the specified authors delineated or described the species. Species are subject to change, whether by evolving into new species, exchanging genes with other species, merging with other species or by becoming extinct. The evolutionary process by which biological populations of sexually-reproducing organisms evolve to become distinct or reproductively isolated as species

6764-414: The presence of humans. For example, Asian black bears may avoid areas with high human activity during the day, but go to these locations during twilight or nighttime hours. Light pollution impacts crepuscular behaviour because it mimics natural light conditions, leading crepuscular animals to behave as they would on nights with more moonlight. Many familiar mammal species are crepuscular, including

6853-487: The result of misclassification leading to questions on whether there really are any ring species. The commonly used names for kinds of organisms are often ambiguous: "cat" could mean the domestic cat, Felis catus , or the cat family, Felidae . Another problem with common names is that they often vary from place to place, so that puma, cougar, catamount, panther, painter and mountain lion all mean Puma concolor in various parts of America, while "panther" may also mean

6942-586: The ring. Ring species thus present a difficulty for any species concept that relies on reproductive isolation. However, ring species are at best rare. Proposed examples include the herring gull – lesser black-backed gull complex around the North pole, the Ensatina eschscholtzii group of 19 populations of salamanders in America, and the greenish warbler in Asia, but many so-called ring species have turned out to be

7031-508: The same species. This concept was narrowed in 2006 to a similarity of 98.7%. The average nucleotide identity (ANI) method quantifies genetic distance between entire genomes , using regions of about 10,000 base pairs . With enough data from genomes of one genus, algorithms can be used to categorize species, as for Pseudomonas avellanae in 2013, and for all sequenced bacteria and archaea since 2020. Observed ANI values among sequences appear to have an "ANI gap" at 85–95%, suggesting that

7120-529: The same species. When two species names are discovered to apply to the same species, the older species name is given priority and usually retained, and the newer name considered as a junior synonym, a process called synonymy . Dividing a taxon into multiple, often new, taxa is called splitting . Taxonomists are often referred to as "lumpers" or "splitters" by their colleagues, depending on their personal approach to recognising differences or commonalities between organisms. The circumscription of taxa, considered

7209-506: The species concept and making taxonomy unstable. Yet others defend this approach, considering "taxonomic inflation" pejorative and labelling the opposing view as "taxonomic conservatism"; claiming it is politically expedient to split species and recognise smaller populations at the species level, because this means they can more easily be included as endangered in the IUCN red list and can attract conservation legislation and funding. Unlike

7298-429: The summer, they eat large numbers of mountain hare and other small mammals. In winter, when they are confined to their retreats by frost and snow, they feed on wild berries, rodents , hares, and even small musk deer . They also hunt ermine , small weasels and birds. Sometimes, sables follow the tracks of wolves and bears and feed on the remains of their kills. They eat gastropods such as slugs, which they rub on

7387-485: The theoretical difficulties. If species were fixed and clearly distinct from one another, there would be no problem, but evolutionary processes cause species to change. This obliges taxonomists to decide, for example, when enough change has occurred to declare that a lineage should be divided into multiple chronospecies , or when populations have diverged to have enough distinct character states to be described as cladistic species. Species and higher taxa were seen from

7476-510: The thickest parts of woods. These burrows are commonly made more secure by being dug among tree roots. They are good climbers of cliffs and trees. They are primarily crepuscular , hunting during the hours of twilight, but become more active in the day during the mating season. Their dens are well hidden, and lined by grass and shed fur, but may be temporary, especially during the winter, when the animal travels more widely in search of prey. Sables are omnivores , and their diet varies seasonally. In

7565-877: The time of Aristotle until the 18th century as categories that could be arranged in a hierarchy, the great chain of being . In the 19th century, biologists grasped that species could evolve given sufficient time. Charles Darwin 's 1859 book On the Origin of Species explained how species could arise by natural selection . That understanding was greatly extended in the 20th century through genetics and population ecology . Genetic variability arises from mutations and recombination , while organisms themselves are mobile, leading to geographical isolation and genetic drift with varying selection pressures . Genes can sometimes be exchanged between species by horizontal gene transfer ; new species can arise rapidly through hybridisation and polyploidy ; and species may become extinct for

7654-573: The time of day an animal is active. Predators hunt when their prey is available, and prey try to avoid the times when their principal predators are at large. The temperature may be too high at midday or too low at night. Some creatures may adjust their activities depending on local competition. The word crepuscular derives from the Latin crepusculum ("twilight"). Its sense accordingly differs from diurnal and nocturnal behavior, which respectively peak during hours of daytime and night. The distinction

7743-462: The time. Sable fur was a favourite of Henry VIII , who once received five sets of sable fur worth £400 from Emperor Charles V . Henry later decreed that sable fur was to be worn only by nobles exceeding the rank of viscount . The Russian conquest of Siberia was largely spurred by the availability of sables there. Ivan Grozny once demanded an annual tribute of 30,000 sable pelts from the newly conquered Kazan Tatars , though they never sent more than

7832-540: The wild. It is difficult to define a species in a way that applies to all organisms. The debate about species concepts is called the species problem. The problem was recognised even in 1859, when Darwin wrote in On the Origin of Species : I was much struck how entirely vague and arbitrary is the distinction between species and varieties. He went on to write: No one definition has satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of

7921-442: The wild. Sables can interbreed with pine martens . This has been observed in the wild, where the two species overlap in the Ural Mountains , and is sometimes deliberately encouraged on fur farms. The resulting hybrid, referred to as a kidus , is slightly smaller than a pure sable, with coarser fur, but otherwise similar markings, and a long bushy tail. Kiduses are typically sterile , although there has been one recorded instance of

#459540