Polyploidy is a condition in which the cells of an organism have more than two paired sets of ( homologous ) chromosomes . Most species whose cells have nuclei ( eukaryotes ) are diploid , meaning they have two complete sets of chromosomes, one from each of two parents; each set contains the same number of chromosomes, and the chromosomes are joined in pairs of homologous chromosomes. However, some organisms are polyploid . Polyploidy is especially common in plants. Most eukaryotes have diploid somatic cells , but produce haploid gametes (eggs and sperm) by meiosis . A monoploid has only one set of chromosomes, and the term is usually only applied to cells or organisms that are normally diploid. Males of bees and other Hymenoptera , for example, are monoploid. Unlike animals, plants and multicellular algae have life cycles with two alternating multicellular generations . The gametophyte generation is haploid, and produces gametes by mitosis ; the sporophyte generation is diploid and produces spores by meiosis .
155-528: The olive , botanical name Olea europaea , meaning 'European olive', is a species of small tree or shrub in the family Oleaceae , found traditionally in the Mediterranean Basin , with wild subspecies found further afield in Africa and western Asia . When in shrub form, it is known as Olea europaea ' Montra ' , dwarf olive , or little olive . The species is cultivated in all
310-409: A Pneumocystis carinii infection, which indicates a weak immune system. Triploidy may be the result of either digyny (the extra haploid set is from the mother) or diandry (the extra haploid set is from the father). Diandry is mostly caused by reduplication of the paternal haploid set from a single sperm, but may also be the consequence of dispermic (two sperm) fertilization of the egg. Digyny
465-636: A hybrid genome with two sets of chromosomes derived from Triticum urartu and two sets of chromosomes derived from Aegilops speltoides . Each chromosome pair derived from the Triticum urartu parent is homoeologous to the opposite chromosome pair derived from the Aegilops speltoides parent, though each chromosome pair unto itself is homologous . Examples in animals are more common in non-vertebrates such as flatworms , leeches , and brine shrimp . Within vertebrates, examples of stable polyploidy include
620-410: A miscarriage ; those that do survive to term typically die shortly after birth. In some cases, survival past birth may be extended if there is mixoploidy with both a diploid and a triploid cell population present. There has been one report of a child surviving to the age of seven months with complete triploidy syndrome. He failed to exhibit normal mental or physical neonatal development, and died from
775-423: 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
930-400: 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
1085-424: 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
1240-511: A city wall, will be long in falling to decay if tied in this manner. Olives were one of the main elements in ancient Israelite cuisine . Olive oil was used for not only food and cooking, but also lighting, sacrificial offerings, ointment , and anointment for priestly or royal office. The olive tree is one of the first plants mentioned in the Hebrew Bible , and one of the most significant. An olive branch (or leaf, depending on translation)
1395-428: 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
1550-432: 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
1705-466: A distance from the sea, which in Greece invariably means up mountain slopes. Greek myth attributed to the primordial culture-hero Aristaeus the understanding of olive husbandry, along with cheese-making and bee-keeping. Olive was one of the woods used to fashion the most primitive Greek cult figures , called xoana , referring to their wooden material; they were reverently preserved for centuries. It
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#17327725489601860-452: A few months with brine or salt packing. With the exception of California style and salt-cured olives, all methods of curing involve a major fermentation involving bacteria and yeast that is of equal importance to the final table olive product. Traditional cures, using the natural microflora on the fruit to induce fermentation, lead to two important outcomes: the leaching out and breakdown of oleuropein and other unpalatable phenolic compounds, and
2015-508: 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
2170-693: A highly successful commercial venture from the 1860s onward. In Japan, the first successful planting of olive trees happened in 1908 on Shodo Island , which became the cradle of olive cultivation in Japan. In 2016, olive oil production started in India , with olive saplings planted in Rajasthan's Thar Desert . Favoured by climate warming, several small-scale olive production farms have also been established at fairly high latitudes in Europe and North America since
2325-465: 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
2480-492: 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
2635-481: A more common path to allopolyploidy because F 1 hybrids between taxa often have relatively high rates of unreduced gamete formation – divergence between the genomes of the two taxa result in abnormal pairing between homoeologous chromosomes or nondisjunction during meiosis. In this case, allopolyploidy can actually restore normal, bivalent meiotic pairing by providing each homoeologous chromosome with its own homologue. If divergence between homoeologous chromosomes
2790-403: A paleopolyploid. It is a middle aged polyploid. Often this refers to whole genome duplication followed by intermediate levels of diploidization. Ancient genome duplications probably occurred in the evolutionary history of all life. Duplication events that occurred long ago in the history of various evolutionary lineages can be difficult to detect because of subsequent diploidization (such that
2945-449: 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
3100-400: 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
3255-565: A piece of the trunk, the root, a twig, or a stake. According to Pliny the Elder a vine, a fig tree and an olive tree grew in the middle of the Roman Forum ; the olive was planted to provide shade. (The garden was recreated in the 20th century). The Roman poet Horace mentions it in reference to his own diet, which he describes as very simple: "As for me, olives, endives , and smooth mallows provide sustenance." Lord Monboddo comments on
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#17327725489603410-695: A polyploid starts to behave cytogenetically as a diploid over time) as mutations and gene translations gradually make one copy of each chromosome unlike the other copy. Over time, it is also common for duplicated copies of genes to accumulate mutations and become inactive pseudogenes. In many cases, these events can be inferred only through comparing sequenced genomes . Examples of unexpected but recently confirmed ancient genome duplications include baker's yeast ( Saccharomyces cerevisiae ), mustard weed/thale cress ( Arabidopsis thaliana ), rice ( Oryza sativa ), and two rounds of whole genome duplication (the 2R hypothesis ) in an early evolutionary ancestor of
3565-960: A rare genetic mutation, E. peregrina is not sterile. On the other hand, polyploidization can also be a mechanism for a kind of 'reverse speciation', whereby gene flow is enabled following the polyploidy event, even between lineages that previously experienced no gene flow as diploids. This has been detailed at the genomic level in Arabidopsis arenosa and Arabidopsis lyrata . Each of these species experienced independent autopolyploidy events (within-species polyploidy, described below), which then enabled subsequent interspecies gene flow of adaptive alleles, in this case stabilising each young polyploid lineage. Such polyploidy-enabled adaptive introgression may allow polyploids at act as 'allelic sponges', whereby they accumulate cryptic genomic variation that may be recruited upon encountering later environmental challenges. Polyploid types are labeled according to
3720-442: A rock to hasten the fermentation process. The olives are stored for a period of up to a year in a container with salt water, lemon juice, lemon peels, laurel and olive leaves, and rosemary. Some recipes may contain white vinegar or olive oil. Most commonly applied to green olive preparation, around 60% of all the world's table olives are produced with this method. Olives are soaked in lye (dilute NaOH, 2–4%) for 8–10 hours to hydrolyse
3875-400: 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,
4030-502: A single primary cultivar and a secondary cultivar selected for its ability to fertilize the primary one. In recent times, efforts have been directed at producing hybrid cultivars with qualities useful to farmers, such as resistance to disease, quick growth, and larger or more consistent crops. Fossil evidence indicates that the olive tree had its origins 20–40 million years ago in the Oligocene , in what now corresponds to Italy and
4185-404: 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
4340-523: 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
4495-400: 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
4650-491: 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
4805-685: 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
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4960-528: 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
5115-517: 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
5270-447: 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
5425-515: 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,
5580-422: A very close succession of ties made of charred olive wood, binding the two faces of the wall together like pins, to give it lasting endurance. For that is a material which neither decay, nor the weather, nor time can harm, but even though buried in the earth or set in the water it keeps sound and useful forever. And so not only city walls but substructures in general and all walls that require a thickness like that of
5735-438: 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
5890-400: 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
6045-452: 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 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
6200-458: 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
6355-743: Is also the most recommended and best possible oil for the lighting of the Shabbat candles . Due to its importance in the Hebrew Bible, the olive has significant national meaning in modern Israeli culture. Two olive branches appear as part of Israel's emblem and the olive tree is Israel's national tree. [1] Apart from being mentioned in the Hebrew Bible (the Christian Old Testament ), olives play an important role in Christianity. The Mount of Olives , east of Jerusalem ,
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6510-414: 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
6665-412: 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,
6820-403: 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
6975-446: Is dotted by past and recent whole-genome duplication events (see Albertin and Marullo 2012 for review). Several examples of polyploids are known: In addition, polyploidy is frequently associated with hybridization and reticulate evolution that appear to be highly prevalent in several fungal taxa. Indeed, homoploid speciation (hybrid speciation without a change in chromosome number) has been evidenced for some fungal species (such as
7130-698: Is even across the two subgenomes, this can theoretically result in rapid restoration of bivalent pairing and disomic inheritance following allopolyploidization. However multivalent pairing is common in many recently formed allopolyploids, so it is likely that the majority of meiotic stabilization occurs gradually through selection. Because pairing between homoeologous chromosomes is rare in established allopolyploids, they may benefit from fixed heterozygosity of homoeologous alleles. In certain cases, such heterozygosity can have beneficial heterotic effects, either in terms of fitness in natural contexts or desirable traits in agricultural contexts. This could partially explain
7285-885: Is frequent in plants, some estimates suggesting that 30–80% of living plant species are polyploid, and many lineages show evidence of ancient polyploidy ( paleopolyploidy ) in their genomes. Huge explosions in angiosperm species diversity appear to have coincided with the timing of ancient genome duplications shared by many species. It has been established that 15% of angiosperm and 31% of fern speciation events are accompanied by ploidy increase. Polyploid plants can arise spontaneously in nature by several mechanisms, including meiotic or mitotic failures, and fusion of unreduced (2 n ) gametes. Both autopolyploids (e.g. potato ) and allopolyploids (such as canola, wheat and cotton) can be found among both wild and domesticated plant species. Most polyploids display novel variation or morphologies relative to their parental species, that may contribute to
7440-671: 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
7595-726: 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,
7750-465: Is highest in Greece, followed by Italy and Spain. The composition of olive oil varies with the cultivar, elevation, time of harvest and extraction process. It consists mainly of oleic acid (up to 83%), with smaller amounts of other fatty acids including linoleic acid (up to 21%) and palmitic acid (up to 20%). Extra virgin olive oil is required to have no more than 0.8% free acidity and fruity flavor characteristics. Table olives are classified by
7905-807: Is mentioned several times in the New Testament . The Allegory of the Olive Tree in St Paul's Epistle to the Romans refers to the scattering and gathering of Israel. It compares the Israelites to a tame olive tree and the Gentiles to a wild olive branch. The olive tree itself, as well as olive oil and olives, play an important role in the Bible. The olive tree and olive oil are mentioned seven times in
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#17327725489608060-514: Is more rarely diagnosed than triploidy, but is observed in 1–2% of early miscarriages. However, some tetraploid cells are commonly found in chromosome analysis at prenatal diagnosis and these are generally considered 'harmless'. It is not clear whether these tetraploid cells simply tend to arise during in vitro cell culture or whether they are also present in placental cells in vivo . There are, at any rate, very few clinical reports of fetuses/infants diagnosed with tetraploidy mosaicism. Mixoploidy
8215-411: Is more subdued than other methods. The brine is changed on a regular basis to help remove the phenolic compounds, and a series of progressively stronger concentrations of salt are added until the product is fully stabilized and ready to be eaten. Applied to green, semi-ripe, or ripe olives, these are soaked in water or weak brine and this solution is changed on a daily basis for 10–14 days. The oleuropein
8370-473: Is most commonly caused by either failure of one meiotic division during oogenesis leading to a diploid oocyte or failure to extrude one polar body from the oocyte . Diandry appears to predominate among early miscarriages , while digyny predominates among triploid zygotes that survive into the fetal period. However, among early miscarriages, digyny is also more common in those cases less than 8 + 1 ⁄ 2 weeks gestational age or those in which an embryo
8525-433: Is most commonly induced by treating seeds with the chemical colchicine . Some crops are found in a variety of ploidies: tulips and lilies are commonly found as both diploid and triploid; daylilies ( Hemerocallis cultivars) are available as either diploid or tetraploid; apples and kinnow mandarins can be diploid, triploid, or tetraploid. Besides plants and animals, the evolutionary history of various fungal species
8680-499: Is naturally dissolved and leached into the water and removed during a continual soak-wash cycle. Fermentation takes place during the water treatment stage and involves a mixed yeast/bacteria ecosystem. Sometimes, the olives are lightly cracked with a blunt instrument to trigger fermentation and speed up the fermentation process. Once debittered, the olives are brined to concentrations of 8–12% NaCl and acid corrected and are then ready to eat. Species A species ( pl. : species)
8835-403: 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
8990-478: 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
9145-623: Is often associated with apomictic mating systems. In agricultural systems, autotriploidy can result in seedlessness, as in watermelons and bananas . Triploidy is also utilized in salmon and trout farming to induce sterility. Rarely, autopolyploids arise from spontaneous, somatic genome doubling, which has been observed in apple ( Malus domesticus ) bud sports . This is also the most common pathway of artificially induced polyploidy, where methods such as protoplast fusion or treatment with colchicine , oryzalin or mitotic inhibitors are used to disrupt normal mitotic division, which results in
9300-440: Is part of cytology and, more specifically, cytogenetics . Although the replication and transcription of DNA is highly standardized in eukaryotes , the same cannot be said for their karyotypes, which are highly variable between species in chromosome number and in detailed organization despite being constructed out of the same macromolecules. In some cases, there is even significant variation within species. This variation provides
9455-435: Is present. There are also two distinct phenotypes in triploid placentas and fetuses that are dependent on the origin of the extra haploid set. In digyny, there is typically an asymmetric poorly grown fetus , with marked adrenal hypoplasia and a very small placenta . In diandry, a partial hydatidiform mole develops. These parent-of-origin effects reflect the effects of genomic imprinting . Complete tetraploidy
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#17327725489609610-536: Is produced by the yeast fermentation, lactic, acetic, or citric acid is often added to the fermentation stage to stabilize the process. Applied to green, semi-ripe, or ripe olives, they are soaked in lye typically for longer periods than Spanish style (e.g. 10–72 hours) until the solution has penetrated three-quarters of the way into the fruit. They are then washed and immediately brined and acid corrected with citric acid to achieve microbial stability. Fermentation still occurs carried out by acidogenic yeast and bacteria but
9765-412: Is quite commonly observed in human preimplantation embryos and includes haploid/diploid as well as diploid/tetraploid mixed cell populations. It is unknown whether these embryos fail to implant and are therefore rarely detected in ongoing pregnancies or if there is simply a selective process favoring the diploid cells. A polyploidy event occurred within the stem lineage of the teleost fish. Polyploidy
9920-586: 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,
10075-433: 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. Tetraploid Polyploidy is the result of whole-genome duplication during
10230-665: Is table olives which can be stored without refrigeration. Fermentations dominated by lactic acid bacteria are, therefore, the most suitable method of curing olives. Yeast-dominated fermentations produce a different suite of metabolites which provide poorer preservation, so they are corrected with an acid such as citric acid in the final processing stage to provide microbial stability. The many types of preparations for table olives depend on local tastes and traditions. The most important commercial examples are listed below. Applied to green, semiripe, or ripe olives. Olives are soaked in salt water for 24–48 hours. Then they are slightly crushed with
10385-640: Is the Coast Redwood Sequoia sempervirens , which is a hexaploid (6 x ) with 66 chromosomes (2 n = 6 x = 66), although the origin is unclear. Aquatic plants, especially the Monocotyledons , include a large number of polyploids. The induction of polyploidy is a common technique to overcome the sterility of a hybrid species during plant breeding. For example, triticale is the hybrid of wheat ( Triticum turgidum ) and rye ( Secale cereale ). It combines sought-after characteristics of
10540-603: Is the plant Erythranthe peregrina . Sequencing confirmed that this species originated from E. × robertsii , a sterile triploid hybrid between E. guttata and E. lutea, both of which have been introduced and naturalised in the United Kingdom. New populations of E. peregrina arose on the Scottish mainland and the Orkney Islands via genome duplication from local populations of E. × robertsii . Because of
10695-594: 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 ,
10850-433: Is typically gnarled and twisted. The small, white, feathery flowers , with ten-cleft calyx and corolla , two stamens , and bifid stigma , are borne generally on the previous year's wood, in racemes springing from the axils of the leaves. The fruit is a small drupe 1–2.5 cm ( 3 ⁄ 8 –1 in) long when ripe, thinner-fleshed and smaller in wild plants than in orchard cultivars. Olives are harvested in
11005-555: Is under- or over-represented are said to be aneuploid (from the Greek words meaning "not", "good", and "fold"). Aneuploidy refers to a numerical change in part of the chromosome set, whereas polyploidy refers to a numerical change in the whole set of chromosomes. Polyploidy occurs in some tissues of animals that are otherwise diploid, such as human muscle tissues. This is known as endopolyploidy . Species whose cells do not have nuclei, that is, prokaryotes , may be polyploid, as seen in
11160-514: The Acropolis ; it was still to be seen there in the second century AD; and when Pausanias was shown it c. 170 AD, he reported "Legend also says that when the Persians fired Athens the olive was burnt down, but on the very day it was burnt it grew again to the height of two cubits ." Indeed, olive suckers sprout readily from the stump, and the great age of some existing olive trees shows that it
11315-530: 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
11470-687: The International Olive Council (IOC) into three groups according to the degree of ripeness achieved before harvesting: Raw or fresh olives are naturally very bitter; to make them palatable, olives must be cured and fermented , thereby removing oleuropein , a bitter phenolic compound that can reach levels of 14% of dry matter in young olives. In addition to oleuropein, other phenolic compounds render freshly picked olives unpalatable and must also be removed or lowered in quantity through curing and fermentation. Generally speaking, phenolics reach their peak in young fruit and are converted as
11625-724: The Linear B syllabic script. The olive tree, Olea europaea , is an evergreen tree or shrub native to Mediterranean Europe, Asia, and Africa. It is short and squat and rarely exceeds 8–15 m (25–50 ft) in height. 'Pisciottana', a unique variety comprising 40,000 trees found only in the area around Pisciotta in the Campania region of southern Italy , often exceeds this, with correspondingly large trunk diameters. The silvery green leaves are oblong, measuring 4–10 cm ( 1 + 1 ⁄ 2 –4 in) long and 1–3 cm ( 3 ⁄ 8 – 1 + 3 ⁄ 16 in) wide. The trunk
11780-633: The Minoan civilization . The ancestry of the cultivated olive is unknown. Fossil olea pollen has been found in Macedonia and other places around the Mediterranean, indicating that this genus is an original element of the Mediterranean flora. Fossilized leaves of olea were found in the palaeosols of the volcanic Greek island of Santorini and dated to about 37,000 BP . Imprints of larvae of olive whitefly Aleurobus olivinus were found on
11935-503: The Quran , and the olive is praised as a precious fruit. Olive tree and olive oil health benefits have been propounded in prophetic medicine. Muhammad is reported to have said: "Take oil of olive and massage with it – it is a blessed tree" ( Sunan al-Darimi , 69:103). Olives are substitutes for dates (if not available) during Ramadan fasting, and olive tree leaves are used as incense in some Muslim Mediterranean countries. In Palestine
12090-546: The basidiomycota Microbotryum violaceum ). As for plants and animals, fungal hybrids and polyploids display structural and functional modifications compared to their progenitors and diploid counterparts. In particular, the structural and functional outcomes of polyploid Saccharomyces genomes strikingly reflect the evolutionary fate of plant polyploid ones. Large chromosomal rearrangements leading to chimeric chromosomes have been described, as well as more punctual genetic modifications such as gene loss. The homoealleles of
12245-399: 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
12400-507: 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
12555-664: The salmonids and many cyprinids (i.e. carp ). Some fish have as many as 400 chromosomes. Polyploidy also occurs commonly in amphibians; for example the biomedically important genus Xenopus contains many different species with as many as 12 sets of chromosomes (dodecaploid). Polyploid lizards are also quite common. Most are sterile and reproduce by parthenogenesis ; others, like Liolaemus chiliensis , maintain sexual reproduction. Polyploid mole salamanders (mostly triploids) are all female and reproduce by kleptogenesis , "stealing" spermatophores from diploid males of related species to trigger egg development but not incorporating
12710-420: The vertebrates (which includes the human lineage) and another near the origin of the teleost fishes . Angiosperms ( flowering plants ) have paleopolyploidy in their ancestry. All eukaryotes probably have experienced a polyploidy event at some point in their evolutionary history. A karyotype is the characteristic chromosome complement of a eukaryote species . The preparation and study of karyotypes
12865-460: The vine , but he makes clear (in 1.16.10) that the cultivated olive must be vegetatively propagated; indeed, the pits give rise to thorny, wild-type olives, spread far and wide by birds. Theophrastus reports how the bearing olive can be grafted on the wild olive, for which the Greeks had a separate name, kotinos . In his Enquiry into Plants (2.1.2–4) he states that the olive can be propagated from
13020-406: 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
13175-633: The Mediterranean region as the source of olive oil ; it is one of the core ingredients in Middle Eastern and Mediterranean cuisines . Thousands of cultivars of the olive tree are known. Olive cultivars may be used primarily for oil, eating, or both. Olives cultivated for consumption are generally referred to as "table olives". About 80% of all harvested olives are turned into oil, while about 20% are used as table olives. The word olive derives from Latin ŏlīva 'olive fruit; olive tree', possibly through Etruscan 𐌀𐌅𐌉𐌄𐌋𐌄 ( eleiva ) from
13330-626: 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
13485-498: The Spanish type fermentation process, but the lye treatment process is skipped and the olives are placed directly in fermentation vessels full of brine (8–12% NaCl). The brine is changed on a regular basis to help remove the phenolic compounds. As the caustic treatment is avoided, lactic acid bacteria are only present in similar numbers to yeast and appear to be outdone by the abundant yeasts found on untreated olives. As very little acid
13640-528: The United Nations adopted in 1946 is a world map with two olive branches. The olive tree, Olea europaea , has been cultivated for olive oil, fine wood, olive leaf , ornamental reasons, and the olive fruit. About 80% of all harvested olives are turned into oil, while about 20% are used as table olives. The olive is one of the "trinity" or "triad" of basic ingredients in Mediterranean cuisine ,
13795-405: 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
13950-425: The agamic complexes of Crepis . Some plants are triploid. As meiosis is disturbed, these plants are sterile, with all plants having the same genetic constitution: Among them, the exclusively vegetatively propagated saffron crocus ( Crocus sativus ). Also, the extremely rare Tasmanian shrub Lomatia tasmanica is a triploid sterile species. There are few naturally occurring polyploid conifers . One example
14105-575: The allotetraploid yeast S. pastorianus show unequal contribution to the transcriptome . Phenotypic diversification is also observed following polyploidization and/or hybridization in fungi, producing the fuel for natural selection and subsequent adaptation and speciation. Other eukaryotic taxa have experienced one or more polyploidization events during their evolutionary history (see Albertin and Marullo, 2012 for review). The oomycetes , which are non-true fungi members, contain several examples of paleopolyploid and polyploid species, such as within
14260-570: 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
14415-492: The archaic Proto-Greek form *ἐλαίϝα (* elaíwa ) ( Classic Greek ἐλαία elaía 'olive fruit; olive tree'. The word oil originally meant 'olive oil', from ŏlĕum , ἔλαιον ( élaion 'olive oil'). The word for 'oil' in multiple other languages also ultimately derives from the name of this tree and its fruit. The oldest attested forms of the Greek words are Mycenaean 𐀁𐀨𐀷 , e-ra-wa , and 𐀁𐀨𐀺 , e-ra-wo or 𐀁𐁉𐀺 , e-rai-wo , written in
14570-567: The basis for a range of studies in what might be called evolutionary cytology. Homoeologous chromosomes are those brought together following inter-species hybridization and allopolyploidization , and whose relationship was completely homologous in an ancestral species. For example, durum wheat is the result of the inter-species hybridization of two diploid grass species Triticum urartu and Aegilops speltoides . Both diploid ancestors had two sets of 7 chromosomes, which were similar in terms of size and genes contained on them. Durum wheat contains
14725-474: 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
14880-505: 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,
15035-428: 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
15190-437: The common name of durum or macaroni wheat, and hexaploid (six sets of chromosomes) with the common name of bread wheat. Many agriculturally important plants of the genus Brassica are also tetraploids. Sugarcane can have ploidy levels higher than octaploid . Polyploidization can be a mechanism of sympatric speciation because polyploids are usually unable to interbreed with their diploid ancestors. An example
15345-465: The community that do not possess land. This is practised through the tradition of leaving fruit on a tree during the harvest so that those who do not have land and are unable to take part in the harvest can still reap the benefits. The Great Seal of the United States first used in 1782 depicts an eagle clutching an olive branch in one of its talons, indicating the power of peace. The Flag of
15500-433: 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
15655-416: 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 a two-part name , called a "binomial". The first part of a binomial is the genus to which the species belongs. The second part
15810-528: The countries of the Mediterranean , as well as in Australia, New Zealand, North and South America and South Africa. It is the type species for its genus, Olea . The tree and its fruit give their name to the Oleaceae plant family, which also includes species such as lilac , jasmine , forsythia , and the true ash tree . The olive's fruit, also called an "olive", is of major agricultural importance in
15965-407: The diploid species. A similar relationship exists between three diploid species of Tragopogon ( T. dubius , T. pratensis , and T. porrifolius ) and two allotetraploid species ( T. mirus and T. miscellus ). Complex patterns of allopolyploid evolution have also been observed in animals, as in the frog genus Xenopus . Organisms in which a particular chromosome, or chromosome segment,
16120-560: The early 21st century. There were an estimated 865 million olive trees in the world as of 2005, and the vast majority of these were found in Mediterranean countries, with traditionally marginal areas accounting for no more than 25% of olive-planted area and 10% of oil production. Olives are thought to have been domesticated in the third millennium BC at the latest, at which point they, along with grain and grapes, became part of Colin Renfrew 's Mediterranean triad of staple crops that fueled
16275-657: The eastern Mediterranean Basin. Around 100,000 years ago, olives were used by humans in Africa, on the Atlantic coast of Morocco, for fuel and most probably for consumption. Wild olive trees, or oleasters, have been collected in the Eastern Mediterranean since ~19,000 BP. The genome of cultivated olives reflects their origin from oleaster populations in the Eastern Mediterranean. The olive plant
16430-643: The emergence of more complex societies. Olives, and especially (perfumed) olive oil, became a major export product during the Minoan and Mycenaean periods. Dutch archaeologist Jorrit Kelder proposed that the Mycenaeans sent shipments of olive oil, probably alongside live olive branches, to the court of the Egyptian pharaoh Akhenaten as a diplomatic gift. In Egypt, these imported olive branches may have acquired ritual meanings, as they are depicted as offerings on
16585-581: The ends of a spectrum of divergence between parental subgenomes. Polyploids that fall between these two extremes, which are often referred to as segmental allopolyploids, may display intermediate levels of polysomic inheritance that vary by locus. About half of all polyploids are thought to be the result of autopolyploidy, although many factors make this proportion hard to estimate. Allopolyploids or amphipolyploids or heteropolyploids are polyploids with chromosomes derived from two or more diverged taxa. As in autopolyploidy, this primarily occurs through
16740-435: 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
16895-477: The evolution of species. It may occur due to abnormal cell division , either during mitosis, or more commonly from the failure of chromosomes to separate during meiosis or from the fertilization of an egg by more than one sperm. In addition, it can be induced in plants and cell cultures by some chemicals: the best known is colchicine , which can result in chromosome doubling, though its use may have other less obvious consequences as well. Oryzalin will also double
17050-471: The evolved polyploids. The high degree of homology among duplicated chromosomes causes autopolyploids to display polysomic inheritance . This trait is often used as a diagnostic criterion to distinguish autopolyploids from allopolyploids, which commonly display disomic inheritance after they progress past the neopolyploid stage. While most polyploid species are unambiguously characterized as either autopolyploid or allopolyploid, these categories represent
17205-581: The existing chromosome content. Among mammals , a high frequency of polyploid cells is found in organs such as the brain, liver, heart, and bone marrow. It also occurs in the somatic cells of other animals , such as goldfish , salmon , and salamanders . It is common among ferns and flowering plants (see Hibiscus rosa-sinensis ), including both wild and cultivated species . Wheat , for example, after millennia of hybridization and modification by humans, has strains that are diploid (two sets of chromosomes), tetraploid (four sets of chromosomes) with
17360-613: The four expected if it were truly a tetraploid. This rodent is not a rat , but kin to guinea pigs and chinchillas . Its "new" diploid (2 n ) number is 102 and so its cells are roughly twice normal size. Its closest living relation is Octomys mimax , the Andean Viscacha-Rat of the same family, whose 2 n = 56. It was therefore surmised that an Octomys -like ancestor produced tetraploid (i.e., 2 n = 4 x = 112) offspring that were, by virtue of their doubled chromosomes, reproductively isolated from their parents. Polyploidy
17515-436: The frog, Xenopus (an extension of the work of Briggs and King in 1952) that were able to develop to the tadpole stage. The British scientist J. B. S. Haldane hailed the work for its potential medical applications and, in describing the results, became one of the first to use the word " clone " in reference to animals. Later work by Shinya Yamanaka showed how mature cells can be reprogrammed to become pluripotent, extending
17670-422: The fruit matures. Once ripening occurs, the levels of phenolics sharply decline through their conversion to other organic products, which render some cultivars edible immediately. One example of an edible olive native to the island of Thasos is the throubes black olive, which becomes edible when allowed to ripen in the sun, shrivel, and fall from the tree. The curing process may take from a few days with lye, to
17825-425: The fusion of unreduced (2 n ) gametes, which can take place before or after hybridization . In the former case, unreduced gametes from each diploid taxon – or reduced gametes from two autotetraploid taxa – combine to form allopolyploid offspring. In the latter case, one or more diploid F 1 hybrids produce unreduced gametes that fuse to form allopolyploid progeny. Hybridization followed by genome duplication may be
17980-509: The fusion of unreduced (2 n ) gametes, which results in either triploid ( n + 2 n = 3 n ) or tetraploid (2 n + 2 n = 4 n ) offspring. Triploid offspring are typically sterile (as in the phenomenon of triploid block ), but in some cases they may produce high proportions of unreduced gametes and thus aid the formation of tetraploids. This pathway to tetraploidy is referred to as the triploid bridge . Triploids may also persist through asexual reproduction . In fact, stable autotriploidy in plants
18135-421: The generation of favourable metabolites from bacteria and yeast, such as organic acids, probiotics, glycerol, and esters, which affect the sensory properties of the final table olives. Mixed bacterial/yeast olive fermentations may have probiotic qualities. Lactic acid is the most important metabolite, as it lowers the pH, acting as a natural preservative against the growth of unwanted pathogenic species. The result
18290-653: The genus Phytophthora . Some species of brown algae ( Fucales , Laminariales and diatoms ) contain apparent polyploid genomes. In the Alveolata group, the remarkable species Paramecium tetraurelia underwent three successive rounds of whole-genome duplication and established itself as a major model for paleopolyploid studies. Each Deinococcus radiodurans bacterium contains 4-8 copies of its chromosome . Exposure of D. radiodurans to X-ray irradiation or desiccation can shatter its genomes into hundred of short random fragments. Nevertheless, D. radiodurans
18445-563: The green to purple stage. O. europaea contains a pyrena commonly referred to in American English as a "pit", and in British English as a "stone". The six natural subspecies of Olea europaea are distributed over a wide range: The subspecies europaea is divided into two varieties , the europaea , which was formerly named Olea sativa , with the seedlings called "olivasters", and silvestris , which corresponds to
18600-429: The large bacterium Epulopiscium fishelsoni . Hence ploidy is defined with respect to a cell. A monoploid has only one set of chromosomes and the term is usually only applied to cells or organisms that are normally diploid. The more general term for such organisms is haploid . A polyploid that is newly formed. That has become polyploid in more recent history; it is not as new as a neopolyploid and not as old as
18755-756: The leaves. The same insect is commonly found today on olive leaves, showing that the plant-animal co-evolutionary relations have not changed since that time. Other leaves found on the same island are dated back to 60,000 BP, making them the oldest known olives from the Mediterranean. Olives are not native to the Americas . Spanish colonists brought the olive to the New World , where its cultivation prospered in present-day Peru, Chile, Uruguay and Argentina. The first seedlings from Spain were planted in Lima by Antonio de Rivera in 1560. Olive tree cultivation quickly spread along
18910-518: The males' DNA into the offspring. While some tissues of mammals, such as parenchymal liver cells, are polyploid, rare instances of polyploid mammals are known, but most often result in prenatal death. An octodontid rodent of Argentina 's harsh desert regions, known as the plains viscacha rat ( Tympanoctomys barrerae ) has been reported as an exception to this 'rule'. However, careful analysis using chromosome paints shows that there are only two copies of each chromosome in T. barrerae , not
19065-500: The natural microbiota present on the olives that survive the lye treatment process. Many organisms are involved, usually reflecting the local conditions or terroir of the olives. During a typical fermentation gram-negative enterobacteria flourish in small numbers at first but are rapidly outgrown by lactic acid bacteria species such as Leuconostoc mesenteroides , Lactobacillus plantarum , Lactobacillus brevis and Pediococcus damnosus . These bacteria produce lactic acid to help lower
19220-408: The number of chromosome sets in the nucleus . The letter x is used to represent the number of chromosomes in a single set: Autopolyploids are polyploids with multiple chromosome sets derived from a single taxon . Two examples of natural autopolyploids are the piggyback plant, Tolmiea menzisii and the white sturgeon, Acipenser transmontanum . Most instances of autopolyploidy result from
19375-483: 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
19530-616: The old wildly growing Mediterranean species O. oleaster , with the seedlings called "oleasters". The sylvestris is characterized by a smaller, shrubby tree that produces smaller fruits and leaves. The subspecies O. e. cerasiformis is tetraploid , and O. e. maroccana is hexaploid . Wild-growing forms of the olive are sometimes treated as the species Olea oleaster , or "oleaster." The trees referred to as " white " and " black " olives in Southeast Asia are not actually olives but species of Canarium . Hundreds of cultivars of
19685-408: The oleuropein. They are usually considered "treated" when the lye has penetrated two-thirds of the way into the fruit. They are then washed once or several times in water to remove the caustic solution and transferred to fermenting vessels full of brine at typical concentrations of 8–12% NaCl. The brine is changed on a regular basis to help remove the phenolic compounds. Fermentation is carried out by
19840-401: The olive in 1779 as one of the foods preferred by the ancients and as one of the most perfect foods. Vitruvius describes of the use of charred olive wood in tying together walls and foundations in his De Architectura : The thickness of the wall should, in my opinion, be such that armed men meeting on top of it may pass one another without interference. In the thickness there should be set
19995-541: The olive tree and plant carry the symbolic connotations of resilience, health, ancestral ties and community. Researchers have found that the olive tree is tied into the Palestinians' Sutra, A’wana and Sumud . The tree is a means of survival and security, represents their bond to their land, community and animals. Olive trees also serve as a symbol of their identities, which include their physical and emotional aspects and their socio-cultural values. Palestinian people view
20150-411: The olive tree are known. An olive's cultivar has a significant impact on its colour, size, shape, and growth characteristics, as well as the qualities of olive oil. Olive cultivars may be used primarily for oil, eating, or both. Olives cultivated for consumption are generally referred to as "table olives". Since many olive cultivars are self-sterile or nearly so, they are generally planted in pairs with
20305-435: The olive trees as the first witnesses that Palestine is their homeland. The harvest season is referred to as "Palestine’s wedding" and is considered a national holiday when schools close for two days so that pupils and teachers can join in the harvest. This holiday allows community and family members to gather and serves as a ritual that encompasses their values surrounding family, labour, community and aid for other members of
20460-589: The other two being wheat for bread , pasta , and couscous ; and the grape for wine . Olive oil is a liquid fat obtained from olives, produced by pressing whole olives and extracting the oil. It is commonly used in cooking, for frying foods or as a salad dressing . It is also used in cosmetics , pharmaceuticals , and soaps , and as a fuel for traditional oil lamps , and has additional uses in some religions. Spain accounts for almost half of global olive oil production; other major producers are Portugal, Italy, Tunisia, Greece and Turkey. Per capita consumption
20615-553: The pH of the brine and therefore stabilize the product against unwanted pathogenic species. A diversity of yeasts then accumulate in sufficient numbers to help complete the fermentation alongside the lactic acid bacteria. Yeasts commonly mentioned include the teleomorphs Pichia anomala , Pichia membranifaciens , Debaryomyces hansenii and Kluyveromyces marxianus . Once fermented, the olives are placed in fresh brine and acid corrected, to be ready for market. Applied to green, semiripe and ripe olives, they are almost identical to
20770-593: 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
20925-417: The parents, but the initial hybrids are sterile. After polyploidization, the hybrid becomes fertile and can thus be further propagated to become triticale. In some situations, polyploid crops are preferred because they are sterile. For example, many seedless fruit varieties are seedless as a result of polyploidy. Such crops are propagated using asexual techniques, such as grafting . Polyploidy in crop plants
21080-674: 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
21235-721: The possibilities to non-stem cells. Gurdon and Yamanaka were jointly awarded the Nobel Prize in 2012 for this work. True polyploidy rarely occurs in humans, although polyploid cells occur in highly differentiated tissue, such as liver parenchyma , heart muscle, placenta and in bone marrow. Aneuploidy is more common. Polyploidy occurs in humans in the form of triploidy , with 69 chromosomes (sometimes called 69, XXX), and tetraploidy with 92 chromosomes (sometimes called 92, XXXX). Triploidy, usually due to polyspermy , occurs in about 2–3% of all human pregnancies and ~15% of miscarriages. The vast majority of triploid conceptions end as
21390-550: The prevalence of allopolyploidy among crop species. Both bread wheat and triticale are examples of an allopolyploids with six chromosome sets. Cotton , peanut , and quinoa are allotetraploids with multiple origins. In Brassicaceous crops, the Triangle of U describes the relationships between the three common diploid Brassicas ( B. oleracea , B. rapa , and B. nigra ) and three allotetraploids ( B. napus , B. juncea , and B. carinata ) derived from hybridization among
21545-796: The processes of speciation and eco-niche exploitation. The mechanisms leading to novel variation in newly formed allopolyploids may include gene dosage effects (resulting from more numerous copies of genome content), the reunion of divergent gene regulatory hierarchies, chromosomal rearrangements, and epigenetic remodeling, all of which affect gene content and/or expression levels. Many of these rapid changes may contribute to reproductive isolation and speciation. However, seed generated from interploidy crosses , such as between polyploids and their parent species, usually have aberrant endosperm development which impairs their viability, thus contributing to polyploid speciation . Polyploids may also interbreed with diploids and produce polyploid seeds, as observed in
21700-460: The production of aneuploid gametes. Natural or artificial selection for fertility can quickly stabilize meiosis in autopolyploids by restoring bivalent pairing during meiosis. Rapid adaptive evolution of the meiotic machinery, resulting in reduced levels of multivalents (and therefore stable autopolyploid meiosis) has been documented in Arabidopsis arenosa and Arabidopsis lyrata , with specific adaptive alleles of these species shared between only
21855-419: The production of polyploid cells. This process can be useful in plant breeding, especially when attempting to introgress germplasm across ploidal levels. Autopolyploids possess at least three homologous chromosome sets, which can lead to high rates of multivalent pairing during meiosis (particularly in recently formed autopolyploids, also known as neopolyploids) and an associated decrease in fertility due to
22010-487: 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
22165-586: 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
22320-508: 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
22475-529: 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
22630-506: 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
22785-533: The valleys of South America's dry Pacific coast where the climate was similar to the Mediterranean. Spanish missionaries established the tree in the 18th century in California . It was first cultivated at Mission San Diego de Alcalá in 1769 or later around 1795. Orchards were started at other missions, but in 1838, an inspection found only two olive orchards in California. Cultivation for oil gradually became
22940-450: The wall of the Aten temple and were used in wreaths for the burial of Tutankhamun . It is likely that, as well as being used for culinary purposes, olive oil was also used to various other ends, including as a perfume. The ancient Greeks smeared olive oil on their bodies and hair as a matter of grooming and good health. Olive oil was used to anoint kings and athletes in ancient Greece. It
23095-540: 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
23250-634: Was brought back to Noah by a dove to demonstrate that the flood was over ( Book of Genesis 8:11). The olive is listed in Deuteronomy 8:8 as one of the seven species that are noteworthy products of the Land of Israel . According to the Halakha , the Jewish law mandatory for all Jews , the olive is one of the seven species that require the recitation of me'eyn shalosh after they are consumed. Olive oil
23405-476: Was burnt in the sacred lamps of temples and was the "eternal flame" of the original Olympic games. Victors in these games were crowned with its leaves. In Homer's Odyssey , Odysseus crawls beneath two shoots of olive that grow from a single stock, and in the Iliad , (XVII.53ff) there is a metaphoric description of a lone olive tree in the mountains, by a spring; the Greeks observed that the olive rarely thrives at
23560-511: Was first cultivated some 7,000 years ago in Mediterranean regions. For thousands of years olives were grown primarily for lamp oil, with little regard for culinary flavor. Its origin can be traced to the Levant based on written tablets, olive pits, and wood fragments found in ancient tombs. As far back as 3000 BC, olives were grown commercially in Crete and may have been the source of the wealth of
23715-412: Was induced in fish by Har Swarup (1956) using a cold-shock treatment of the eggs close to the time of fertilization, which produced triploid embryos that successfully matured. Cold or heat shock has also been shown to result in unreduced amphibian gametes, though this occurs more commonly in eggs than in sperm. John Gurdon (1958) transplanted intact nuclei from somatic cells to produce diploid eggs in
23870-732: Was possible that the olive tree of the Acropolis dated to the Bronze Age. The olive was sacred to Athena and appeared on the Athenian coinage. According to another myth, Elaea was an accomplished athlete killed by her fellow athletes who had grown envious of her; but Athena and Gaia turned her into an olive tree as reward. Theophrastus, in On the Causes of Plants , does not give as systematic and detailed an account of olive husbandry as he does of
24025-520: Was purely a matter of local pride that the Athenians claimed that the olive grew first in Athens. In an archaic Athenian foundation myth , Athena won the patronage of Attica from Poseidon with the gift of the olive. According to the fourth-century BC father of botany, Theophrastus , olive trees ordinarily attained an age around 200 years, he mentions that the very olive tree of Athena still grew on
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