111-468: Taxus baccata is a species of evergreen tree in the family Taxaceae, native to Western Europe , Central Europe and Southern Europe , as well as Northwest Africa , northern Iran, and Southwest Asia . It is the tree originally known as yew , though with other related trees becoming known, it may be referred to as common yew , European yew , or in North America English yew . It
222-451: A Celtic language , see Gaulish *ivos , Breton ivin, Irish ēo , Welsh yw (ywen) and French if . In German it is known as Eibe . Baccata is Latin for 'bearing berries'. The word yew as it was originally used seems to refer to the colour brown. The yew (μίλος) was known to Theophrastus , who noted its preference for mountain coolness and shade, its evergreen character and its slow growth. Most Romance languages, with
333-423: 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
444-400: 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
555-424: 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
666-501: A branch of a yew tree to the tombs of those who had died recently so they would be guided in their return to the Land of Shadows. The yew tree has been found near chapels, churches, and cemeteries since ancient times as a symbol of the transcendence of death. They are often found in the main squares of villages where people celebrated the open councils that served as a way of general assembly to rule village affairs. It has been suggested that
777-428: 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
888-432: 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
999-620: A forest canopy, but is tolerant of soil pH when planted by humans, such as their traditional placement in churchyards and cemeteries , where some of the largest and oldest trees in northwestern Europe are found. It grows well in well-drained soils, tolerating nearly any soil type, typically humus and base-rich soils, but also on rendzina and sand soils given adequate moisture. They can survive temporary flooding and moderate droughts. Roots can penetrate extremely compressed soils, such as on rocky terrain and vertical cliff faces. T. baccata normally appears individually or in small groups within
1110-508: 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
1221-534: A good trunk much wood has to be discarded. There was a tradition of planting yew trees in churchyards throughout Britain and Ireland, among other reasons, as a resource for bows, such as at " Ardchattan Priory whose yew trees, according to other accounts, were inspected by Robert the Bruce and cut to make at least some of the longbows used at the Battle of Bannockburn ." The trade of yew wood to England for longbows
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#17327828560241332-682: A hundred for sixteen pounds. In 1507 the Holy Roman Emperor asked the Duke of Bavaria to stop cutting yew, but the trade was profitable, and in 1532 the royal monopoly was granted for the usual quantity "if there are that many." In 1562, the Bavarian government sent a long plea to the Holy Roman Emperor asking him to stop the cutting of yew, and outlining the damage done to the forests by its selective extraction, which broke
1443-465: 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
1554-492: 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
1665-533: A new form. Yew wood was historically important, finding use in the Middle Ages in items such as musical instruments, furniture, and longbows . The species was felled nearly to extinction in much of Europe. In the modern day it is not considered a commercial crop due to its very slow growth, but it is valued for hedging and topiary . Certain compounds found in the bark of yew trees were discovered in 1967 to have efficacy as anti-cancer agents. The precursors of
1776-560: A number of place names. These include the Proto-Celtic eburos ; Old Irish ibar ; Irish iobhar , iubhar and iúr ; and the Scottish Gaelic iubhar , Newry , Northern Ireland is an anglicization of An Iúraigh , an oblique form of An Iúrach , which means "the grove of yew trees". The modern Irish name for Newry is An tIúr (pronounced [ənʲ ˈtʲuːɾˠ]), which means "the yew tree". An tIúr
1887-449: 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
1998-400: 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
2109-400: 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,
2220-404: 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
2331-523: 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
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#17327828560242442-400: 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
2553-491: 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
2664-685: 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
2775-528: 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
2886-517: 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
2997-400: A trunk up to 2 m (6 ft 7 in) (exceptionally 4 m or 13 ft 1 in) in diameter. The bark is thin, scaly brown, and comes off in small flakes aligned with the stem. The leaves are flat, dark green, 1–4 centimetres ( 1 ⁄ 2 – 1 + 1 ⁄ 2 in) long, 2–3 mm ( 3 ⁄ 32 – 1 ⁄ 8 in) broad, and arranged spirally on the stem, but with
3108-447: 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
3219-515: 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,
3330-399: A wide range of soils and situations, including shallow chalk soils and shade, although in deep shade its foliage may be less dense. However it cannot tolerate waterlogging, and in poorly-draining situations is liable to succumb to the root-rotting pathogen Phytophthora cinnamomi . Species A species ( pl. : species) is a population of organisms in which any two individuals of
3441-558: Is 8–15 mm ( 5 ⁄ 16 – 9 ⁄ 16 in) long and wide and open at the end. The arils mature 6 to 9 months after pollination, and with the seed contained, are eaten by thrushes , waxwings and other birds, which disperse the hard seeds undamaged in their droppings. Maturation of the arils is spread over 2 to 3 months, increasing the chances of successful seed dispersal. The seeds themselves are poisonous and bitter, but are opened and eaten by some bird species, including hawfinches , greenfinches , and great tits . The aril
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3552-438: 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
3663-400: 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
3774-458: 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
3885-618: Is a shortening of Iúr Cinn Trá , "yew tree at the head of the strand", which was formerly the most common Irish name for Newry. This relates to an apocryphal story that Saint Patrick planted a yew tree there in the 5th century. The Irish name Cathair an Iúir (City of Newry) appears on some bilingual signs around the city. The area of Ydre in the South Swedish highlands is interpreted to mean "place of yews". Two localities in particular, Idhult and Idebo , appear to be further associated with yews. York ( Old Norse : Jórvík )
3996-513: Is a woodland tree in its native range, and is also grown as an ornamental tree, hedge or topiary. The plant is poisonous, with toxins that can be absorbed through inhalation, ingestion, and transpiration through the skin. Consuming any part of the tree, excluding the aril, can be deadly and the consumption of even a small amount of the foliage can result in death. The word yew is from Old English īw, ēow , ultimately from Proto-Indo-European *h₁eyHw- . Possibly entered Germanic languages through
4107-414: 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
4218-412: 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,
4329-702: Is derived from the Brittonic name Eburākon ( Latinised variously as Eboracum , Eburacum , or Eburaci ), a combination of *eburos "yew-tree" and a suffix of appurtenance *-āko(n) "belonging to-, place of-" (compare Welsh -og ) meaning "place of the yew trees" ( efrog in Welsh , Old Irish iubrach "grove of yew trees, place with one or more yew trees", iúrach in Irish Gaelic and iùbhrach in Scottish Gaelic);
4440-403: 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
4551-523: Is estimated to be over 400,000 years old. Yew is also associated with Wales and England because of the longbow , an early weapon of war developed in northern Europe, and as the English longbow the basis for a medieval tactical system. The oldest surviving yew longbow was found at Rotten Bottom in Dumfries and Galloway , Scotland. It has been given a calibrated radiocarbon date of 4040 BC to 3640 BC and
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4662-671: 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
4773-726: 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,
4884-634: Is known as Teixu l'Iglesia in the Asturian language . It stands 15 m (49 ft) tall with a trunk diameter of 6.82 m (22 ft 4 + 1 ⁄ 2 in) and a crown diameter of 15 m (49 ft). It was declared a Natural Monument on April 27, 1995, by the Asturian Government and is protected by the Plan of Natural Resources. A unique forest formed by Taxus baccata and European box ( Buxus sempervirens ) lies within
4995-403: 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
5106-658: Is not poisonous; it is gelatinous and very sweet tasting. The male cones are globose, 3–6 mm ( 1 ⁄ 8 – 1 ⁄ 4 in) in diameter, and shed their pollen in early spring. Yews are mostly dioecious , but occasional individuals can be variably monoecious, or change sex with time. T. baccata is native to all countries of Europe (except Iceland), the Caucasus, and beyond from Turkey eastwards to northern Iran. Its range extends south to Morocco and Algeria in North Africa. A few populations are also present in
5217-478: 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
5328-499: Is on display in the National Museum of Scotland . Yew is the wood of choice for longbow making; the heartwood is always on the inside of the bow with the sapwood on the outside. This makes most efficient use of their properties as heartwood is best in compression whilst sapwood is superior in tension. However, much yew is knotty and twisted, and therefore unsuitable for bowmaking; most trunks do not give good staves and even in
5439-579: Is said up to 40 people could stand inside one of the La-Haye-de-Routot yew trees, and the Le Ménil-Ciboult yew is probably the largest, with a girth of 13 m. Yews may grow to become exceptionally large (over 5 m diameter) and may live to be over 2,000 years old. Sometimes monks planted yews in the middle of their cloister , as at Muckross Abbey (Ireland) or abbaye de Jumièges (Normandy). Some ancient yew trees are located at St. Mary
5550-586: 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,
5661-418: 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. Hawfinch Too Many Requests If you report this error to
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#17327828560245772-495: Is that yews were planted to discourage farmers and drovers from letting animals wander onto the burial grounds, the poisonous foliage being the disincentive. A further possible reason is that fronds and branches of yew were often used as a substitute for palms on Palm Sunday . King Edward I of England ordered yew trees planted in churchyards to protect the buildings. Some yews existed before their churches, as preachers held services beneath them when churches were unavailable. Due to
5883-594: 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 ,
5994-492: The Crann Ogham —the variation on the ancient Irish Ogham alphabet which consists of a list of trees—yew is the last in the main list of 20 trees, primarily symbolizing death. There are stories of people who have committed suicide by ingesting the foliage. As the ancient Celts also believed in the transmigration of the soul , there is in some cases a secondary meaning of the eternal soul that survives death to be reborn in
6105-530: 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
6216-552: The Jura Mountains and Alpine foothills . In England it grows best in steep slopes of the chalk downs , forming extensive stands invading the grassland outside the beech woods. In more continental climates of Europe it fares better in mixed forests , of both coniferous and mixed broadleaf-conifer composition. Under its evergreen shade, no other plants can grow. T. baccata prefers steep rocky calcareous slopes. It rarely develops beyond saplings on acid soil when under
6327-537: The Statute of Westminster in 1472, every ship coming to an English port had to bring four bowstaves for every tun . Richard III of England increased this to ten for every tun. This stimulated a vast network of extraction and supply, which formed part of royal monopolies in southern Germany and Austria. In 1483, the price of bowstaves rose from two to eight pounds per hundred, and in 1510 the Venetians would only sell
6438-572: The chemotherapy drug paclitaxel (taxol) were later shown to be synthesized easily from extracts of the leaves of European yew, which is a much more renewable source than the bark of the Pacific yew ( Taxus brevifolia ) from which they were initially isolated. This ended a point of conflict in the early 1990s; many environmentalists, including Al Gore , had opposed the destructive harvesting of Pacific yew for paclitaxel cancer treatments. Docetaxel can then be obtained by semi-synthetic conversion from
6549-401: 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 a two-part name , called a "binomial". The first part of a binomial is the genus to which the species belongs. The second part
6660-399: 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
6771-507: 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
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#17327828560246882-452: The sacred tree at the Temple at Uppsala was an ancient yew tree. The Christian church commonly found it expedient to take over existing pre-Christian sacred sites for churches. It has also been suggested that yews were planted at religious sites as their long life was suggestive of eternity, or because, being toxic when ingested, they were seen as trees of death. Another suggested explanation
6993-477: The understory , but also forms stands throughout its range, such as in sheltered calcareous sites. T. baccata is extremely shade-tolerant, with the widest temperature range for photosynthesis among European trees, able to photosynthesize in winter after deciduous trees have shed their leaves. It can grow under partial canopies of beech and other deciduous broad-leafed trees, though it only grows into large trees without such shade. In centuries past T. baccata
7104-406: 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
7215-577: The 7th century the Old English for 'boar' had become eofor . When the Danish army conquered the city in 866, its name became Jórvík . The Old French and Norman name of Yorks following the Norman Conquest was recorded as Everwic (modern Norman Évèroui ) in works such as Wace's Roman de Rou . Jórvík , meanwhile, gradually reduced to York in the centuries after
7326-484: The Baltic, but at this period bows were being replaced by guns in any case. The late Robert Lundberg, a noted luthier who performed extensive research on historical lute -making methodology, states in his 2002 book Historical Lute Construction that yew was historically a prized wood for lute construction. European legislation establishing use limits and requirements for yew limited supplies available to luthiers, but it
7437-656: The Conquest, moving from the Middle English Yerk in the 14th century through Yourke in the 16th century to Yarke in the 17th century. The form York was first recorded in the 13th century. Many company and place names, such as the Ebor race meeting, refer to the Latinised Brittonic, Roman name. The Archbishop of York uses Ebor as his surname in his signature. In
7548-626: 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
7659-654: The Virgin Church, Overton-on-Dee in Wales. In the Septuagint rendering of the Book of Nahum , 1:10, Nineveh and other deemed enemies of the biblical God are foretold to "be laid bare even to its foundation, and…devoured as a twisted yew." In Asturian tradition and culture, the yew tree was considered to be linked with the land, people, ancestors, and ancient religion. It was tradition on All Saints' Day to bring
7770-405: 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
7881-434: The ability of their branches to root and sprout anew after touching the ground, yews became symbols of death, rebirth, and therefore immortality. In interpretations of Norse cosmology , the tree Yggdrasil has traditionally been interpreted as a giant ash tree . Some scholars now believe errors were made in past interpretations of the ancient writings, and that the tree is most likely a European yew ( Taxus baccata ). In
7992-485: The age of yews is often overestimated. Ten yews in Britain are believed to predate the 10th century. The potential age of yews is impossible to determine accurately and is subject to much dispute. There is rarely any wood as old as the entire tree, while the boughs themselves often become hollow with age, making ring counts impossible. Evidence based on growth rates and archaeological work of surrounding structures suggests
8103-570: 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
8214-565: The ancient Celtic world, the yew tree ( *eburos ) had extraordinary importance; a passage by Caesar narrates that Cativolcus , chief of the Eburones , poisoned himself with yew rather than submit to Rome ( Gallic Wars 6: 31). Similarly, Florus notes that when the Cantabrians were under siege by the legate Gaius Furnius in 22 BC, most of them took their lives either by sword, fire, or a poison extracted ex arboribus taxeis , that is, from
8325-404: The appropriate sexes or mating types can produce fertile offspring , typically by sexual reproduction . It 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
8436-757: The archipelagos of the Azores and Madeira. The limit of its northern Scandinavian distribution is its sensitivity to frost, with global warming predicted to allow its spread inland. It has been introduced elsewhere, including the United States. Aside from its natural habitat, it is also common to find English Yew in gardens because it is very tolerant to pruning, and in cemeteries, as it symbolizes death. T. baccata ' s richest central European populations are in Swiss yew-beech woodlands, on cool, steep marl slopes up to 1,400 metres (4,600 ft) in elevation in
8547-474: 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
8658-505: 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,
8769-428: 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
8880-435: The canopy and allowed wind to destroy neighbouring trees. In 1568, despite a request from Saxony , no royal monopoly was granted because there was no yew to cut, and the next year Bavaria and Austria similarly failed to produce enough yew to justify a royal monopoly. Forestry records in this area in the 17th century do not mention yew, and it seems that no mature trees were to be had. The English tried to obtain supplies from
8991-585: The city itself is called Eabhrach (Irish) and Eabhraig (Scottish Gaelic), from the Latin Eboracum ); or alternatively, "the settlement of (a man named) Eburos " (a Celtic personal name is mentioned in different documents as Eβουρος , Eburus , and Eburius and, when combined with the Celtic possessive suffix * -āko(n) , could be used to denote his property). The 12th‑century chronicler Geoffrey of Monmouth , in his account of
9102-676: The city of Sochi , in the Western Caucasus . The oldest Irish Yew ( Taxus baccata 'Fastigiata'), the Florence Court Yew , still stands in the grounds of the Florence Court estate in County Fermanagh , Northern Ireland . The Irish Yew has become ubiquitous in cemeteries across the world, and it is believed that all known examples are from cuttings from this tree. The entire plant is poisonous, with
9213-433: 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
9324-435: 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
9435-402: The exception of the aril (the red flesh of the “berry” covering the seed). Yews contain numerous toxic compounds, including "at least ten alkaloids, nitriles ( cyanogenic glycoside esters), ephedrine ", and their essential oil , but the most important toxins are taxine alkaloids , cardiotoxic chemical compounds which act via calcium and sodium channel antagonism. If any leaves or seeds of
9546-510: The largest recorded trunk girths in Britain, reportedly 16-17m in the 18th century, and experts estimate it to be 5,000 years old. The Llangernyw Yew in Clwyd , Wales, can be found at another early saint site and is about 4000–5000 years old according to an investigation led by David Bellamy, who also carbon-dated a yew tree in Tisbury at around 4000 years old. A certificate and memorial board by
9657-457: The leaf bases twisted to align the leaves in two flat rows on either side of the stem, except on erect leading shoots where the spiral arrangement is more obvious. The leaves are poisonous. The seed cones are modified, each cone containing a single seed, which is 4–7 mm ( 3 ⁄ 16 – 1 ⁄ 4 in) long, and partly surrounded by a fleshy scale which develops into a soft, bright red berry-like structure called an aril . The aril
9768-572: The notable exception of French ( if ), kept a version of the Latin word taxus (Italian tasso , Corsican tassu , Occitan teis , Catalan teix , Gasconic tech , Spanish tejo , Asturian texu , Portuguese teixo , Galician teixo and Romanian tisă ) from the same root as toxic . In Slavic languages, the same root is preserved: Polish cis , Ukrainian, Slovakian and Russian tis ( тис ), Serbian-Croatian-Bosnian-Montenegrin tisa / тиса , tis , Slovenian tisa . Albanian borrowed it as tis . In Iran ,
9879-483: 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
9990-715: The oldest yews, such as the Fortingall Yew in Perthshire, Scotland, may be in the range of 2,000 years, placing them among the oldest plants in Europe. One characteristic contributing to yews' longevity is that, unlike most other trees, they are able to split under the weight of advanced growth without succumbing to disease in the fracture. Another is their ability to give rise to new epicormic and basal shoots from cut surfaces and low on their trunks, even in old age. The Fortingall Yew in Perthshire, Scotland, has one of
10101-593: 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
10212-674: 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
10323-474: The plant all year, with maximal concentrations appearing during the winter. Dried yew plant material retains its toxicity for several months and even increases its toxicity as the water is removed. Fallen leaves should therefore also be considered toxic. Poisoning usually occurs when leaves of yew trees are eaten, but in at least one case a victim inhaled sawdust from a yew tree. Male yews are extremely allergenic, blooming and releasing abundant amounts of pollen in
10434-506: The plant are ingested, urgent medical attention is recommended as well as observation for at least 6 hours after the point of ingestion. The European yew is one of the most toxic species in the genus, along with the Japanese yew , T. cuspidata . Yew poisonings are relatively common in both domestic and wild animals which consume the plant accidentally, resulting in "countless fatalities in livestock". Taxines are also absorbed efficiently via
10545-570: The precursors. Wood from the yew is classified as a closed-pore softwood , similar to cedar and pine. Easy to work, yew is among the hardest of the softwoods, yet it possesses a remarkable elasticity, making it ideal for products that require springiness, such as bows. The wood is esteemed for cabinetry and tool handles. The hard, slow-growing wood also finds use in gates, furniture, parquet floors , and paneling . Its typical burls and contorted growth, with intricate multicolored patterns, make it attractive for carving and woodturning , but also make
10656-492: The prehistoric kings of Britain, Historia Regum Britanniae , suggests the name derives from that of a pre-Roman city founded by the legendary king Ebraucus . The name Eboracum became the Anglian Eoforwic in the 7th century: a compound of Eofor- , from the old name, and -wic "a village", probably by conflation of the element Ebor- with a Germanic root * eburaz ('boar'); by
10767-487: 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
10878-586: 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
10989-508: 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
11100-529: 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
11211-413: The skin. Taxus species should thus be handled with care and preferably with gloves. "The lethal dose for an adult is reported to be 50 g of yew needles. Patients who ingest a lethal dose frequently die due to cardiogenic shock , in spite of resuscitation efforts." There are currently no known antidotes for yew poisoning, but drugs such as atropine have been used to treat the symptoms. Taxine remains in
11322-506: 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
11433-477: The spring, with an OPALS allergy scale rating of 10 out of 10. Completely female yews have an OPALS rating of 1, the lowest possible, trapping pollen while producing none. The pollen, like most species', easily passes through window screens. While yew pollen does not contain sufficient taxine alkaloids to cause poisoning, its allergenic potential has been implicated in adverse reactions to paclitaxel treatment. Words and Morphemes for "yew tree" have resulted in
11544-850: The tree confirm the tree's age estimate. Other well known yews include the Ankerwycke Yew , the Balderschwang Yew , the Caesarsboom , the Florence Court Yew , and the Borrowdale Fraternal Four, of which poet William Wordsworth wrote. The Kingley Vale National Nature Reserve in West Sussex has one of Europe's largest yew woodlands. The oldest specimen in Spain is located in Bermiego , Asturias . It
11655-417: The tree is known as sorkhdār ( Persian : سرخدار , literally "the red tree"). Common yew was one of the many species first described by Linnaeus . It is one of around 30 conifer species in seven genera in the family Taxaceae , which is placed in the order Pinales . Yews are small to medium-sized evergreen trees, growing 10–20 m (35–65 ft) (exceptionally up to 28 m or 92 ft) tall, with
11766-540: 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
11877-533: The wood unsuited for construction. It is good firewood and is sometimes burnt as incense. Due to all parts of the yew and its volatile oils being poisonous and cardiotoxic, a mask should be worn if one comes in contact with sawdust from the wood. One of the world's oldest surviving wooden artifacts is a Clactonian yew spear head, found in 1911 at Clacton-on-Sea , in Essex , UK. Known as the Clacton Spear , it
11988-613: The yew tree (2: 33, 50–51). In a similar way, Orosius notes that when the Astures were besieged at Mons Medullius , they preferred to die by their own swords or by yew poison rather than surrender (6, 21, 1). The yew is traditionally and regularly found in churchyards in England, Wales, Scotland, Ireland, and Northern France (particularly Normandy ). Some examples can be found in La Haye-de-Routot or La Lande-Patry . It
12099-557: Was apparently as prized among medieval, renaissance, and baroque lute builders as Brazilian rosewood is among contemporary guitar-makers for its quality of sound and beauty. Today European yew is widely used in landscaping and ornamental horticulture. Due to its dense, dark green, mature foliage, and its tolerance of even very severe pruning, it is used especially for formal hedges and topiary . Its relatively slow growth rate means that in such situations it needs to be clipped only once per year (in late summer). European yew will tolerate
12210-440: Was exterminated from many woodlands as a poisonous hazard to the cattle and horses that often grazed in the woods. Rabbits and deer however have a level of immunity to the poisonous alkaloids, and the seeds are dispersed by birds, with thrushes greatly enjoying the fruit. It also regenerates readily from stumps and roots, even when ancient and hollow. Taxus baccata can reach 400 to 600 years of age. Some specimens live longer but
12321-516: Was so robust that it depleted the stocks of good-quality, mature yew over a vast area. The first documented import of yew bowstaves to England was in 1294. In 1423 the Polish king commanded protection of yews in order to cut exports, facing nearly complete destruction of local yew stock. In 1470 compulsory archery practice was renewed, and hazel , ash , and laburnum were specifically allowed for practice bows. Supplies still proved insufficient, until by
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