122-422: The sailfish is one of two species of marine fish in the genus Istiophorus , which belong to the family Istiophoridae ( marlins ). They are predominantly blue to gray in colour and have a characteristically large dorsal fin known as the sail , which often stretches the entire length of the back. Another notable characteristic is the elongated rostrum (bill) consistent with that of other marlins and
244-423: 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
366-400: 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
488-424: 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
610-679: A Portuguese force led by commander Antonio Correia invaded Bahrain to take control of the wealth created by its pearl industry. On April 29, 1602, Shāh Abbās , the Persian emperor of the Safavid Persian Empire , expelled the Portuguese from Bahrain, and that date is commemorated as National Persian Gulf day in Iran . With the support of the British fleet, in 1622 'Abbās took the island of Hormuz from
732-597: A coastline on the Persian Gulf are (clockwise, from north): Iran; Oman 's Musandam exclave ; the United Arab Emirates ; Saudi Arabia; Qatar , on a peninsula off the Saudi coast; Bahrain , an island nation; Kuwait ; and Iraq in the northwest. Various small islands also lie within the Persian Gulf, some of which are the subject of territorial disputes between the states in the region. Exclusive economic zones in
854-508: A combination of fresh and salt water for growth, and act as nurseries for many crabs, small fish, and insects; these fish and insects are the source of food for many of the marine birds that feed on them. Mangroves are a diverse group of shrubs and trees belonging to the genus Avicennia or Rhizophora that flourish in the salt water shallows of the Persian Gulf, and are the most important habitats for small crustaceans that dwell in them. They are as crucial an indicator of biological health on
976-428: 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
1098-432: 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
1220-633: A few coral reefs . Compared to the Red Sea, the coral reefs in the Persian Gulf are relatively few and far between. This is primarily connected to the influx of major rivers, especially the Shatt al-Arab (Euphrates and Tigris), which carry large amounts of sediment (most reef-building corals require strong light) and causes relatively large variations in temperature and salinity (corals in general are poorly suited to large variations). Nevertheless, coral reefs have been found along sections of coast of all countries in
1342-508: A genetic boundary suitable for defining a species concept is present. DNA barcoding has been proposed as a way to distinguish species suitable even for non-specialists to use. One of the barcodes is a region of mitochondrial DNA within the gene for cytochrome c oxidase . A database, Barcode of Life Data System , contains DNA barcode sequences from over 190,000 species. However, scientists such as Rob DeSalle have expressed concern that classical taxonomy and DNA barcoding, which they consider
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#17328481976541464-593: A giant field across the territorial median line (North Field in the Qatari sector; South Pars Field in the Iranian sector). Using this gas, Qatar has built up a substantial liquefied natural gas (LNG) and petrochemical industry. In 2002, the Persian Gulf nations of Bahrain, Iran, Iraq, Kuwait, Qatar, Saudi Arabia, and the UAE produced about 25% of the world's oil, held nearly two-thirds of the world's crude oil reserves , and about 35% of
1586-465: 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
1708-429: A method of confusing prey, displaying emotion, and/or communicating with other sailfish. Sailfish have been documented attacking humans in self-defense; a 100-pound (45-kilogram) sailfish stabbed a woman in the groin when her party tried to catch it. Sailfish have been reported to use their bills for hitting schooling fish by tapping (short-range movement) or slashing (horizontal large-range movement) at them. The sail
1830-492: 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
1952-408: A particular group size. A mathematical model showed that sailfish in groups of up to 70 individuals should gain benefits in this way. The underlying mechanism was termed proto-cooperation because it does not require any spatial coordination of attacks and could be a precursor to more complex forms of group hunting. The bill movement of sailfish during attacks on fish is usually either to the left or to
2074-449: 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
2196-400: 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
2318-400: 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,
2440-404: 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
2562-523: 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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#17328481976542684-400: 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
2806-488: 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
2928-685: 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
3050-519: 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
3172-432: A time, and the small teeth on their bills inflict injuries on their prey fish in terms of scale and tissue removal. Typically, about two prey fish are injured during a sailfish attack, but only 24% of attacks result in capture. As a result, injured fish increase in number over time in a fish school under attack. Given that injured fish are easier to catch, sailfish benefit from the attacks of their conspecifics but only up to
3294-506: 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
3416-447: 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
3538-515: 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,
3660-438: 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
3782-465: Is a diverse cradle for many species who depend on each other for survival. However, the Persian Gulf is not as biologically diverse as the Red Sea . Overall, the wildlife of the Persian Gulf is endangered from both global factors, and regional, local negligence. Most pollution is from ships; land generated pollution counts as the second most common source of pollution. Along the mediterranean regions of
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3904-400: 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
4026-452: 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
4148-458: 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
4270-414: 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
4392-412: 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,
4514-557: Is defined as "A line joining Ràs Limah (25°57'N) on the coast of Arabia and Ràs al Kuh (25°48'N) on the coast of Iran (Persia)". This inland sea of some 251,000 square kilometres (96,912 sq mi) is connected to the Gulf of Oman in the east by the Strait of Hormuz ; and its western end is marked by the major river delta of the Shatt al-Arab , which carries the waters of the Euphrates and
4636-403: 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
4758-470: Is destroyed, or occupied by man-made structures. This has had a negative impact on the crustaceans that rely on the mangrove, and in turn on the species that feed on them. The Persian Gulf and its coastal areas are the world's largest single source of petroleum, and related industries dominate the region. Safaniya Oil Field , the world's largest offshore oilfield , is located in the Persian Gulf. Large gas finds have also been made, with Qatar and Iran sharing
4880-671: 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
5002-726: 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,
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5124-638: Is in the Persian Gulf Basin , which is of Cenozoic origin and related to the subduction of the Arabian Plate under the Zagros Mountains . The current flooding of the basin started 15,000 years ago due to rising sea levels of the Holocene glacial retreat . The International Hydrographic Organization defines the Persian Gulf's southern limit as "The Northwestern limit of Gulf of Oman". This limit
5246-430: Is negatively affected by new developments along the Persian Gulf coastline, particularly the construction of artificial islands by Arab states and pollution from oil spills caused during the "Persian Gulf war" and various other natural and artificial causes. Uncontrolled hunting has also had a negative impact on the survival of dugongs. After Australian waters, which are estimated to contain some 80,000 dugong inhabitants,
5368-403: 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
5490-411: Is normally kept folded down when swimming and only raised when the sailfish attack their prey. The raised sail has been shown to reduce sideways oscillations of the head, which is likely to make the bill less detectable by prey fish. This strategy allows sailfish to put their bills close to fish schools or even into them without being noticed by the prey before hitting them. Sailfish usually attack one at
5612-468: 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
5734-408: Is now the Iranian province of Bushehr , is an example of such commercial port. Siraf, was also significant in that it had a flourishing commercial trade with China by the fourth century, having first established connection with the far east in 185 AD. Portuguese influence in the Persian Gulf lasted for 250 years; however, since the beginning of the 16th century, Portuguese dominance contended with
5856-586: 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,
5978-413: 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. Persian Gulf The Persian Gulf , sometimes called
6100-610: Is still a deficit of 416 cubic kilometres (100 cu mi) per year. This difference is supplied by currents at the Strait of Hormuz . The water from the Persian Gulf has a higher salinity, and therefore exits from the bottom of the Strait, while ocean water with less salinity flows in through the top. Another study revealed the following numbers for water exchanges for the Persian Gulf: evaporation = –1.84 m (6.0 ft)/year, precipitation = 0.08 m (0.26 ft)/year, inflow from
6222-594: 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 ,
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#17328481976546344-502: Is used by the International Hydrographic Organization . The dispute in naming has become especially prevalent since the 1960s. Rivalry between Iran and some Arab states, along with the emergence of pan-Arabism and Arab nationalism , has seen the name "Arabian Gulf" become predominant in most Arab countries. Names beyond these two have also been applied to or proposed for this body of water. The region of
6466-754: The Arabian Gulf , is a mediterranean sea in West Asia . The body of water is an extension of the Indian Ocean located between Iran and the Arabian Peninsula . It is connected to the Gulf of Oman in the east by the Strait of Hormuz . The Shatt al-Arab river delta forms the northwest shoreline. The Persian Gulf has many fishing grounds, extensive reefs (mostly rocky, but also coral ), and abundant pearl oysters , however its ecology has been damaged by industrialization and oil spills . The Persian Gulf
6588-772: The Al Qasimi tribe. This led to the British mounting the Persian Gulf campaign of 1819 . The campaign led to the signing of the General Maritime Treaty of 1820 between the British and the Sheikhs of what was then known as the ' Pirate Coast '. From 1763 until 1971, the British Empire maintained varying degrees of political control over some of the Persian Gulf states, including the United Arab Emirates (originally called
6710-523: 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
6832-551: The Nile in the west, as well as Sind waterway, in India. The Achaemenid high naval command had established major naval bases located along Shatt al-Arab river, Bahrain, Oman, and Yemen. The Persian fleet would soon not only be used for peacekeeping purposes along the Shatt al-Arab but would also open the door to trade with India via Persian Gulf. Following the fall of Achaemenid Empire, and after
6954-501: The Tigris . In Iran , this is called "Arvand Rud" (lit. Swift River ). Its length is 989 kilometres (615 miles), with Iran covering most of the northern coast and Saudi Arabia most of the southern coast. The Persian Gulf is about 56 km (35 mi) wide at its narrowest, in the Strait of Hormuz. Overall, the waters are very shallow, with a maximum depth of 90 metres (295 feet) and an average depth of 50 metres (164 feet). Countries with
7076-526: The Trucial States ) and at various times Bahrain, Kuwait, Oman, and Qatar through the British Residency of the Persian Gulf . The Persian Gulf was a battlefield of the 1980–1988 Iran–Iraq War , in which each side attacked the other's oil tankers . It is the namesake of the 1991 Gulf War , the largely air- and land-based conflict that followed Iraq 's invasion of Kuwait . The United States' role in
7198-446: The collared kingfishers were raised by conservationists over real estate development by the United Arab Emirates and Oman. Estimates from 2006 showed that only three viable nesting sites were available for this ancient bird, one located 80 miles (129 km) from Dubai, and two smaller sites in Oman. Such real estate expansion could prove devastating to this subspecies. A UN plan to protect
7320-399: 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
7442-498: 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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#17328481976547564-423: The swordfish , which together constitute what are known as billfish in sport fishing circles. Sailfish live in colder pelagic waters of all Earth 's oceans, and hold the record for the highest speed of any marine animal. There is a dispute based on the taxonomy of the sailfish, and either one or two species have been recognized. No differences have been found in mtDNA , morphometrics or meristics between
7686-610: The " Persian Corridor ". Britain utilized the Persian Gulf as the entry point for the supply chain in order to make use of the Trans-Iranian Railway . The Persian Gulf therefore became a critical maritime path through which the Allies transported equipment to Soviet Union against the Nazi invasion . The piracy in the Persian Gulf was prevalent until the 19th century. Many of the most notable historical instances of piracy were perpetrated by
7808-406: 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
7930-515: The Arabian Sea, including the Persian Gulf, the Red Sea , the Gulf of Kutch , the Gulf of Suez , the Gulf of Aqaba , the Gulf of Aden , and the Gulf of Oman , dolphins and finless porpoises are the most common marine mammals in the waters, while larger whales and orcas are rarer today. Historically, whales had been abundant in the Persian Gulf before commercial hunts wiped them out. Whales were reduced even further by illegal mass hunts by
8052-463: The Gulf of Aqaba), omura's whale , minke whale , and orca also swim into the Persian Gulf, while many other large species such as blue whale , sei , and sperm whales were once migrants into the Gulf of Oman and off the coasts in deeper waters, and still migrate into the Red Sea, but mainly in deeper waters of outer seas. In 2017, waters of the Persian Gulf along Abu Dhabi were revealed to hold
8174-683: The Lakhum tribe , who lived in what is now Yemen, migrated north and founded the Lakhmid Kingdom along the southern coast. Occasional ancient battles took place along the Persian Gulf coastlines, between the Sassanid Persian empire and the Lakhmid Kingdom, the most prominent of which was the invasion led by Shapur II against the Lakhmids, leading to Lakhmids' defeat, and advancement into Arabia, along
8296-608: The Middle East adjacent to the Gulf. The world's oldest known civilization ( Sumer ) developed along the Persian Gulf and southern Mesopotamia . The oldest evidence in the world for seagoing vessels has been found at H3 in Kuwait, dating to the mid-sixth millennium BC, when the Gulf was part of an extensive trade network that involved the Ubaid settlements in Mesopotamia and communities along
8418-452: The Middle East are located in this region. The wildlife of the Persian Gulf is diverse, and entirely unique because of the Persian Gulf's geographic distribution and its isolation from the international waters only breached by the narrow Strait of Hormuz . The Persian Gulf has hosted some of the most magnificent marine fauna and flora, some of which are near extirpation or at serious environmental risk. From corals, to dugongs , Persian Gulf
8540-622: 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
8662-698: The Pacific and Indian oceans. Sailfish in some areas are reliant on coral reefs as areas for feeding and breeding. As witnessed in the Persian Gulf , the disappearance of coral reefs in a sailfish's habitat may be followed by the disappearance of the species from that area. When freshly hatched, sailfish are hunted by other fishes that mainly survive on eating plankton. The size of their predators increases as they grow, and adult sailfish are not eaten by anything other than larger predatory fish like open ocean shark species and orcas . National Geographic story on sailfish Species A species ( pl. : species)
8784-442: The Persian Gulf by the United Arab Emirates and Oman also raised concerns that habitats of species such as the hawksbill turtle , greater flamingo , and booted warbler may be destroyed. The dolphins that frequent the Persian Gulf in northern waters around Iran are also at risk. Recent statistics and observations show that dolphins are at danger of entrapment in purse seine fishing nets and exposure to chemical pollutants; perhaps
8906-490: The Persian Gulf grew in the second half of the 20th century. On July 3, 1988, Iran Air Flight 655 was shot down by the U.S. military (which had mistaken the Airbus A300 operating the flight for an Iranian F-14 Tomcat ) while it was flying over the Persian Gulf, killing all 290 people on board. The United Kingdom maintains a profile in the region; in 2006 alone, over 1 million British nationals visited Dubai . In 2018,
9028-602: The Persian Gulf has been inhabited since the Paleolithic . During most of the Last Glacial Period (115,000–11,700 years Before Present ), due to lowered sea levels (reaching around 125 metres (410 ft) metres below present values during the Last Glacial Maximum ) combined with the shallow depth of the Gulf (on average around 35 metres (115 ft) and at max around 100 metres (330 ft) metres depth) most of
9150-422: The Persian Gulf in recent years. Aside from direct damage to the coral, the construction waste creates "traps" for marine life in which they are trapped and die. The result has been a dwindling population of the coral, and as a result a decrease in number of species that rely on the corals for their survival. A great example of this symbiosis are the mangroves in the Persian Gulf, which require tidal flow and
9272-517: The Persian Gulf was called Pūdīg , which comes from Avestan : Pūitika , lit. 'cleansing', a name mentioned in Bundahishn . The body of water is historically and internationally known as the Persian Gulf. Arab governments refer to it as the Arabian Gulf or The Gulf, and other countries and organizations have begun using Arabian Gulf. The name Gulf of Iran (Persian Gulf)
9394-614: The Persian Gulf was called many different names. The Assyrians called it the "Bitter Sea". In 550 BC, the Achaemenid Empire established the first ancient empire in Persis ( Pars , or modern Fars , also known as Persia), in the southwestern region of the Iranian plateau . Consequently, in the Greek sources, the body of water that bordered this province came to be known as the "Persian Gulf". In
9516-455: The Persian Gulf was exposed as dry land, forming a flat floodplain where a number of rivers converged. This region may have served as an environmental refuge for early humans during periodic hyperarid climate oscillations. The modern marine Gulf was formed when sea level rose during the early Holocene , from around 12,000 to 6,000 years ago. The flooding of the Gulf may have stimulated the development of Neolithic farming cultures in regions of
9638-448: The Persian Gulf. Corals are vital ecosystems that support multitude of marine species, and whose health directly reflects the health of the Persian Gulf. Recent years have seen a drastic decline in the coral population in the Persian Gulf, partially owing to global warming but mostly to irresponsible dumping by Arab states like the UAE and Bahrain. Construction garbage such as tires, cement, and chemical by products have found their way to
9760-563: The Persian Gulf. Persian naval forces laid the foundation for a strong Persian maritime presence in Persian Gulf, that started with Darius I and existed until the arrival of the British East India Company , and the Royal Navy by mid-19th century AD. Persians were not only stationed on islands of the Persian Gulf, but also had ships often of 100 to 200 capacity patrolling empire's various rivers including Shatt-al-Arab , Tigris , and
9882-587: The Persian Gulf: Countries by coastline length : The Persian Gulf is home to many islands such as Bahrain, an Arab state. Geographically, the biggest island in the Persian Gulf is Qeshm island , belonging to Iran and located in the Strait of Hormuz . Other significant islands in the Persian Gulf include Greater Tunb , Lesser Tunb and Kish administered by Iran, Bubiyan administered by Kuwait, Tarout administered by Saudi Arabia, and Dalma administered by UAE. In recent years, there has also been
10004-441: The Portuguese; much of the trade was diverted to the town of Bandar 'Abbās , which he had taken from the Portuguese in 1615 and had named after himself. The Persian Gulf was therefore opened to a flourishing commerce with the Portuguese, Dutch, French, Spanish and the British merchants, who were granted particular privileges. The Ottoman Empire reasserted itself into Eastern Arabia in 1871. Under military and political pressure from
10126-467: The Soviet Union and Japan in the 1960s and 1970s. Along with Bryde's whales , these once common residents can still can be seen in deeper marginal seas such as Gulf of Aden, Israel coasts, and in the Strait of Hormuz . Other species such as the critically endangered Arabian humpback whale , (also historically common in Gulf of Aden and increasingly sighted in the Red Sea since 2006, including in
10248-426: The Strait = 33.66 m (110.4 ft)/year, outflow from the Strait = -32.11 m (105.3 ft)/year, and the balance is 0 m (0 ft)/year. Data from different 3D computational fluid mechanics models, typically with spatial resolution of 3 kilometres (1.9 mi) and depth each element equal to 1–10 metres (3.3–32.8 ft) are predominantly used in computer models. Before being given its present name,
10370-467: The Strait of Hormuz. Writing the water balance budget for the Persian Gulf, the inputs are river discharges from Iran and Iraq (estimated to be 2,000 cubic metres (71,000 cu ft) per second), as well as precipitation over the sea which is around 180 mm (7.1 in)/year in Qeshm Island . The evaporation of the sea is high, so that after considering river discharge and rain contributions, there
10492-576: The UK opened a permanent military base, HMS Jufair , in the Persian Gulf, the first since it withdrew from East of Suez in 1971 and is developing a support facility in Oman. Eight nations have coasts along the Persian Gulf: Bahrain , Iran , Iraq , Kuwait , Oman , Qatar , Saudi Arabia , and the United Arab Emirates . The Persian gulf's strategic location has made it an ideal place for human development over time. Today, many major cities of
10614-405: 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
10736-652: The addition of artificial islands for tourist attractions , such as The World Islands in Dubai and The Pearl Island in Doha . Persian Gulf islands are often also historically significant, having been used in the past by colonial powers such as the Portuguese and the British in their trade or as acquisitions for their empires. The Persian Gulf is connected to the Indian Ocean through
10858-570: 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
10980-474: 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
11102-505: 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,
11224-471: The book of Nearchus known as Indikê (300 BC), the word "Persikon kolpos" is mentioned for multiple times meaning "Persian gulf". During the years 550 to 330 BC, coinciding with the sovereignty of the Achaemenid Persian Empire over the Middle East area, especially the whole part of the Persian Gulf and some parts of the Arabian Peninsula , the name of "Persian ( Pars ) Sea" is widely found in
11346-428: 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
11468-695: The compiled written texts. At the same period, there is the inscription and engraving of Darius the Great, which belongs to the fifth century BC: King Darius says: I ordered to dig this ( Canal of the Pharaohs ) canal from the river that is called Nile ( Pirâva ) and flows in Egypt ( Mudrâyâ ), to the sea that begins in Persia ( Pârsa ). Therefore, when this canal had been dug as I had ordered, ships went from Egypt through this canal to Persia, as I had intended. In Sassanian times,
11590-433: 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
11712-416: 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
11834-458: The entire Gulf coast. For most of the early history of the settlements in the Persian Gulf, the southern shores were ruled by a series of nomadic tribes. During the end of the fourth millennium BC , the southern part of the Persian Gulf was dominated by the Dilmun civilization. For a long time, the most important settlement on the southern coast of the Persian Gulf was Gerrha . In the second century
11956-435: 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
12078-702: The fall of the Parthian Empire , the Sassanid Empire ruled the northern half and at times the southern half of the Persian Gulf. The Persian Gulf, along with the Silk Road , were important trade routes in the Sassanid Empire. Many of the trading ports of the Persian empires were located in or around Persian Gulf. Siraf , an ancient Sassanid port that was located on the northern shore of the Persian Gulf, located in what
12200-589: The governor of the Ottoman Vilayet of Baghdad , Midhat Pasha , the ruling Al Thani tribe submitted peacefully to Ottoman rule. The Ottomans were forced to withdraw from the area with the start of World War I and the need for troops in various other frontiers. In World War II , the Western Allies used Iran as a conduit to transport military and industrial supply to the USSR, through a pathway known historically as
12322-662: The local powers and the Ottoman Empire. Following the arrival of the English and the Dutch, the Safavid Empire allied with the newcomers to contest Portuguese dominance of the seas in the 17th century. Portuguese expansion into the Indian Ocean in the early 16th century following Vasco da Gama 's voyages of exploration saw them battle the Ottomans up the coast of the Persian Gulf. In 1521,
12444-457: The mangroves as a biological reserve was ignored by the emirate of Sharjah, which allowed the dredging of a channel that bisects the wetland and construction of an adjacent concrete walkway. Environmental watchdogs in Arabia are few, and those that do advocate the wildlife are often silenced or ignored by developers of real estate many of whom have governmental connections. Real estate development in
12566-461: The most alarming sign is the "mass suicides" committed by dolphins off Iran's Hormozgan province, which are not well understood, but are suspected to be linked with a deteriorating marine environment from water pollution from oil, sewage, and industrial run offs. The Persian Gulf is home to over 700 species of fish, most of which are native. Of these 700 species, more than 80% are reef associated. These reefs are primarily rocky, but there are also
12688-423: The most lucrative world supply of oil, and the lack of cooperation between Arab states and Iran, have had a negative impact on the survival of many marine species, including dugongs. The Persian Gulf is also home to many migratory and local birds. There is great variation in color, size, and type of the bird species that call the Persian Gulf home. Concerns regarding the endangerment of the kalbaensis subspecies of
12810-409: The next attack will take place. Taken together, these results suggest a potential novel benefit of group hunting which allows individual predators to specialize in their hunting strategy without becoming predictable to their prey. The injuries that sailfish inflict on their prey appear to reduce their swimming speeds, with injured fish being more frequently found in the back (compared with the front) of
12932-478: 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
13054-585: 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
13176-674: 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
13298-417: The predator will hit. Given that individuals with right- and left-sided preferences are about equally frequent in sailfish populations, living in groups possibly offers a way out of this predictability. The larger the sailfish group, the greater the possibility that individuals with right- and left-sided preferences are about equally frequent. Therefore, prey fish should find it hard to predict in which direction
13420-487: 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
13542-541: The right side. Identification of individual sailfish based on the shape of their dorsal fins identified individual preferences for hitting to the right or left side. The strength of this side preference was positively correlated with capture success. These side-preferences are believed to be a form of behavioural specialization that improves performance. However, a possibility exists that sailfish with strong side preferences could become predictable to their prey because fish could learn after repeated interactions in which direction
13664-573: 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
13786-508: 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
13908-529: 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
14030-484: The school than uninjured ones. When a sardine school is approached by a sailfish, the sardines usually turn away and flee in the opposite direction. As a result, the sailfish usually attacks sardine schools from behind, putting at risk those fish that are the rear of the school because of their reduced swimming speeds. The sailfish is an epipelagic and oceanic species and shows a strong tendency to approach continental coasts, islands and reefs tropical and temperate waters of
14152-599: The southern shorelines. During the seventh century the Sassanid Persian empire conquered the whole of the Persian Gulf, including southern and northern shores. Between 625 BC and 226 AD, the northern side was dominated by a succession of Persian empires including the Median , Achaemenid , Seleucid and Parthian empires. Under the leadership of the Achaemenid king Darius the Great (Darius I), Persian ships found their way to
14274-502: 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
14396-437: The surface of the water, as the corals are to biological health of the Persian Gulf in deeper waters. Mangroves' ability to survive the salt water through intricate molecular mechanisms, their unique reproductive cycle, and their ability to grow in the most oxygen-deprived waters have allowed them extensive growth in hostile areas of the Persian Gulf. However, with the advent of artificial island development, most of their habitat
14518-1003: The two supposed species and most authorities now only recognize a single species, Istiophorus platypterus , found in warmer oceans around the world. FishBase continues to recognize two species: Considered by many scientists the fastest fish in the ocean, sailfish grow quickly, reaching 1.2–1.5 m (4–5 ft) in length in a single year, and feed on the surface or at middle depths on smaller pelagic forage fish and squid . Sailfish were previously estimated to reach maximum swimming speeds of 35 m/s (125 km/h), but research published in 2015 and 2016 indicate sailfish do not exceed speeds between 10–15 m/s (35–55 km/h). During predator–prey interactions, sailfish reached burst speeds of 7 m/s (25 km/h) and did not surpass 10 m/s (35 km/h). Generally, sailfish do not grow to more than 3 m (10 ft) in length and rarely weigh over 90 kilograms (200 pounds). Some sources indicate that sailfish are capable of changing colours as
14640-408: The waters off Qatar, Bahrain, UAE, and Saudi Arabia make the Persian Gulf the second most important habitat for the species, hosting some 7,500 remaining dugongs. However, the current number of dugongs is dwindling, and it is not clear how many are currently alive or what their reproductive trend is. Ambitious and uncalculated construction schemes, political unrest, ever-present international conflict,
14762-537: 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
14884-520: The world's largest population of Indo-Pacific humpbacked dolphins . One of the more unusual marine mammals living in the Persian Gulf is the dugong ( Dugong dugon ). Also called "sea cows", for their grazing habits and mild manner resembling livestock, dugongs have a life expectancy similar to that of humans and they can grow up to 3 metres (9.8 feet) in length. These gentle mammals feed on sea grass and are closer relatives of certain land mammals than are dolphins and whales . Their simple grass diet
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