79-483: The burbot ( Lota lota ), also known as bubbot , mariah , loche , cusk , freshwater cod , freshwater ling , freshwater cusk , the lawyer , coney-fish , lingcod , or eelpout , is a species of coldwater ray-finned fish native to the subarctic regions of the Northern hemisphere . It is the only member of the genus Lota , and is the only freshwater species of the order Gadiformes . The species
158-423: 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
237-515: 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 is between 8 and 8.7 million. About 14% of these had been described by 2011. All species (except viruses ) are given
316-542: 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 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,
395-400: 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
474-424: 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
553-428: 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
632-447: A correspondent from The Tonight Show with Jay Leno did a segment on the event. Burbot populations are difficult to study, due to their deep habitats and reproduction under ice. Although burbot global distribution is widespread and abundant, many populations have been threatened or extirpated. Ichthyologists and taxonomists are strongly advising to look into the old taxonomical due to new genetic insights there are two species of burbot:
711-405: A cross between a catfish and an eel, the burbot has a serpent-like body, but is easily distinguished by a single barbel on the chin. The body is elongated and laterally compressed, with a flattened head and single, tube-like projection for each nostril. The mouth is wide, with both upper and lower jaws having many small teeth. Burbot have two soft dorsal fins , with the first being low and short, and
790-432: 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
869-508: 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
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#1732791642974948-416: A large oil globule, about 1 mm (0.039 in) in diameter and have an optimal incubation range between 1 and 7 °C (34 and 45 °F). Newly hatched burbot larvae are pelagic , passively drifting in the open water. Habitats near 4 °C (39 °F) are optimal for burbot and they prefer water temperatures of 12 °C (54 °F) and lower. By night, juveniles are active, taking shelter during
1027-465: 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 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
1106-492: 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
1185-449: 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
1264-400: A perfect model of life, it is still a useful tool to scientists and conservationists for studying life on Earth, regardless of 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
1343-400: 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,
1422-404: 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
1501-523: 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
1580-400: 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
1659-491: 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
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#17327916429741738-685: 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
1817-528: 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
1896-517: 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
1975-447: 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
2054-515: 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,
2133-484: A wide diet is also correlated to their tendency to bite lures, making them very easy to catch. Burbot are preyed upon by northern pike, muskellunge, and some lamprey species. A book written in 1590 in England notes that burbot were so common that they were used to feed hogs. The burbot is edible. In Finland , its roe and liver are highly regarded as delicacies, as is the fish itself. An annual spearfishing tournament
2212-438: 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
2291-400: 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
2370-458: 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
2449-550: Is a tenacious predator , which sometimes attacks other fish of almost the same size, and as such, can be a nuisance fish in waters where it is not native. Recent discoveries of burbot in the Green River at Flaming Gorge Reservoir in Utah have concerned wildlife biologists, who fear the burbot could decimate the sport-fish population in what is recognized as one of the world's top brown trout fisheries, because it often feeds on
Burbot - Misplaced Pages Continue
2528-863: Is about 40 cm (16 in), with slight sexual dimorphism. Maximum lengths range between 30 and 120 cm (12 and 47 in), and weights range from 1.0 to 12 kg (2.2 to 26.5 lb). At the larval stage, month-old burbot begin exogenous feeding, consuming food through the mouth and digesting in the intestines. Burbot at the larval stage and into the juvenile stage feed on invertebrates based on size. Under 1 cm (0.39 in), burbot eat copepods and cladocerans , and above 1–2 cm (0.39–0.79 in), zooplankton and amphipods . As adults, they are primarily piscivores , preying on lamprey , whitefish , grayling , young northern pike , suckers , stickleback , trout , and perch . At times, burbot also eat insects and other macroinvertebrates , and have been known to eat frogs, snakes, and birds. Having such
2607-414: 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
2686-519: Is closely related to marine fish such as the common ling and cusk , all of which belong to the family Lotidae (rocklings). The name burbot comes from the Latin word barba , meaning beard, referring to its single chin whisker, or barbel . Its generic and specific names, Lota lota , comes from the old French lotte fish, which is also named "barbot" in Old French. With an appearance like
2765-403: 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
2844-671: 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
2923-726: 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,
3002-462: Is held near Roblin, Manitoba . One of the highlights of the tournament is the fish fry, where the day's catch is served deep-fried. When cooked, burbot meat tastes very similar to American lobster , leading to the burbot's nickname of "poor man's lobster". In the 1920s, Minnesota druggist Theodore "Ted" H. Rowell and his father, Joseph Rowell, a commercial fisherman on Lake of the Woods , were using
3081-490: Is lower in viscosity, and more rapidly digested and assimilated than most other fish-liver oils. Rowell went on to found the Burbot Liver Products Company, which later became Rowell Laboratories, Inc. The IGFA recognizes the world-record burbot as caught on Lake Diefenbaker , Saskatchewan, Canada, by Sean Konrad on 27 March 2010. The fish weighed 11.4 kg (25 lb 2 oz). The burbot
3160-403: 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
3239-478: 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
Burbot - Misplaced Pages Continue
3318-436: Is on low priority, being nonexistent in some regions. The Kootenai tribe of Idaho and their partners engaged conservation efforts to the burbot populations. 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 is the basic unit of classification and
3397-586: 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,
3476-421: 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. Thermocline Too Many Requests If you report this error to
3555-594: 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 ,
3634-771: The Bering Strait . In North America, burbot range from the Seward Peninsula in Alaska to New Brunswick along the Atlantic Coast. Burbot are most common in streams and lakes of North America and Europe. They are fairly common in Lake Erie , but are also found in the other Great Lakes . An anadromous population also lives in the brackish waters of the Baltic Sea . Recent genetic analysis suggests
3713-530: 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
3792-399: 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
3871-507: 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
3950-406: 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
4029-568: The European burbot (Lota lota) and the North-American burbot (Lota maculosa). As the burbot lacks popularity in commercial fishing , many regions do not even consider management plans. Pollution and habitat change, such as river damming, appear to be the primary causes for riverine burbot population declines, while pollution and the adverse effects of invasive species have the greatest influence on lacustrine populations. Management of burbot
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#17327916429744108-626: 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
4187-405: 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
4266-570: 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
4345-474: 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
4424-505: 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,
4503-428: The boundaries between closely related species become unclear with hybridisation , in a species complex of hundreds of similar microspecies , and in 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
4582-405: The burbot as feed for the foxes on Joe's blue fox farm. They discovered the burbot contained something that improved the quality of the foxes' furs; this was confirmed by the fur buyers, who commented that these furs were superior to other blue fox furs they were seeing. Ted Rowell felt it was something in the burbot, so he extracted some oil and sent it away to be assayed. The result of the assay
4661-433: 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
4740-407: The day under rocks and other debris. Growing rapidly in their first year, burbot reach between 11 and 12 cm (4.3 and 4.7 in) in total length by late fall. During their second year of life, burbot on average grow another 10 cm (3.9 in). Burbot transition from pelagic habitats to benthic environments as they reach adulthood, around five years old. Average length of burbot by maturity
4819-479: The eggs of other fish in the lake, such as sockeye salmon . The Utah Division of Fish and Game has instituted a "no release" "catch and kill" regulation for the burbot in Utah waterways. However, the regulations have been found to be largely unenforceable. The town of Walker, Minnesota , holds an International Eelpout Festival every winter on Leech Lake . The festival received national attention on 4 March 2011, when
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#17327916429744898-435: 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
4977-667: The geographic pattern of burbot may indicate multiple species or subspecies, making this single taxon somewhat misleading. In the United Kingdom , the burbot is possibly extinct. The last recorded capture was a specimen weighing 0.48 kg (1 lb 1 oz), in July 1970, by Stephen Mackinder, from the Cut-off Channel or the Great Ouse Relief Channel , at Denver , Norfolk . In October 1970, it
5056-483: 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
5135-593: 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
5214-674: 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
5293-487: 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
5372-586: 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
5451-508: 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
5530-529: 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
5609-502: The second being much longer. The anal fin is low and almost as long as the dorsal fin. The caudal fin is rounded, the pectoral fins are fan-shaped, and pelvic fins are narrow with an elongated second fin ray. Having such small fins relative to body size indicates a benthic lifestyle with low swimming endurance, unable to withstand strong currents. Burbot have circumpolar distribution above 40° N. Populations are continuous from France across Europe and chiefly Russian Asia to
5688-506: 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
5767-456: The strongest candidates for areas in which the species might yet survive. Plans to reintroduce this freshwater member of the cod family back into British waters are under investigation. Burbot live in large, cold rivers, lakes, and reservoirs, primarily preferring freshwater habitats, but able to thrive in brackish environments for spawning. For some time of the year, the burbot lives under ice, and it requires frigid temperatures to breed. During
5846-449: The summer, they are typically found in the colder water below the thermocline . In Lake Superior, burbot can live at depths below 300 m (980 ft). As benthic fish , they tolerate an array of substrate types, including mud, sand, rubble, boulder, silt, and gravel, for feeding. Adults construct extensive burrows in the substrate for shelter during the day. Burbot are active crepuscular hunters. Burbot populations are adfluvial during
5925-704: The water column to drift and settle. When spawning, many male burbot gather around one or two females, forming a spawning ball. Writhing in the open water, males and females simultaneously release sperm and eggs. Depending on water temperatures, the incubation period of the eggs lasts from 30 to 128 days. Fertilized eggs then drift until they settle into cracks and voids in the substrate. Depending on body size, female burbot fecundity ranges from 63,000 to 3,478,000 eggs for each clutch. Rate of growth, longevity, and age of sexual maturity of burbot are strongly correlated with water temperature; large, older individuals produce more eggs than small, younger individuals. Eggs are round with
6004-540: 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
6083-551: The winter, and they migrate to near-shore reefs and shoals to spawn, preferring spawning grounds of sand or gravel. Burbot reach sexual maturity at between four and seven years of age. Spawning season typically occurs between December and March, often under ice at extremely low temperatures ranging between 1 and 4 °C. During a relatively short season lasting from two to three weeks, burbot spawn multiple times, but not every year. As broadcast spawners, burbot do not have an explicit nesting site, but rather release eggs and sperm into
6162-575: Was described in the Guinness Book of Records as the "rarest British fish" which was "almost extinct", so it had been "agreed that no record for this species should be published, at least until 1974, in the interests of conservation". The burbot may still survive in the UK. The counties of Cambridgeshire , Norfolk and Yorkshire (particularly the River Derwent or Yorkshire Ouse ) seem to be
6241-409: Was that the liver of the burbot has three to four times the potency in vitamin D, and four to 10 times in vitamin A, than "good grades" of cod-liver oil. Their vitamin content varies from lake to lake, where their diets may have some variation. Additionally, liver makes up about 10% of the fish's total body weight, and its liver is six times the size of those of freshwater fish of comparable size. The oil
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