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19,200 | The messages, protocols, and structural components of DRDA are defined by the Distributed Data Management Architecture. Distributed SQL processing ala DRDA is distinctive from contemporary distributed SQL databases. | https://en.wikipedia.org/wiki?curid=29004 |
19,201 | SQL deviates in several ways from its theoretical foundation, the relational model and its tuple calculus. In that model, a table is a set of tuples, while in SQL, tables and query results are lists of rows; the same row may occur multiple times, and the order of rows can be employed in queries (e.g. in the LIMIT claus... | https://en.wikipedia.org/wiki?curid=29004 |
19,202 | Critics argue that SQL should be replaced with a language that returns strictly to the original foundation: for example, see "The Third Manifesto". | https://en.wikipedia.org/wiki?curid=29004 |
19,203 | Early specifications did not support major features, such as primary keys. Result sets could not be named, and subqueries had not been defined. These were added in 1992. | https://en.wikipedia.org/wiki?curid=29004 |
19,204 | The lack of sum types has been described as a roadblock to full use of SQL's user-defined types. JSON support, for example, needed to be added by a new standard in 2016. | https://en.wikipedia.org/wiki?curid=29004 |
19,205 | The concept of Null is the subject of some debates. The Null marker indicates the absence of a value, and is distinct from a value of 0 for an integer column or an empty string for a text column. The concept of Nulls enforces the 3-valued-logic in SQL, which is a concrete implementation of the general 3-valued logic. | https://en.wikipedia.org/wiki?curid=29004 |
19,206 | Another popular criticism is that it allows duplicate rows, making integration with languages such as Python, whose data types might make accurately representing the data difficult, in terms of parsing and by the absence of modularity. | https://en.wikipedia.org/wiki?curid=29004 |
19,207 | This is usually avoided by declaring a primary key, or a unique constraint, with one or more columns that uniquely identify a row in the table. | https://en.wikipedia.org/wiki?curid=29004 |
19,208 | In a similar sense to object–relational impedance mismatch, a mismatch occurs between the declarative SQL language and the procedural languages in which SQL is typically embedded. | https://en.wikipedia.org/wiki?curid=29004 |
19,209 | "Constructed types" are one of ARRAY, MULTISET, REF(erence), or ROW. "User-defined types" are comparable to classes in object-oriented language with their own constructors, observers, mutators, methods, inheritance, overloading, overwriting, interfaces, and so on. "Predefined data types" are intrinsically supported by ... | https://en.wikipedia.org/wiki?curid=29004 |
19,210 | In biology, taxonomy () is the scientific study of naming, defining (circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxa (singular: taxon) and these groups are given a taxonomic rank; groups of a given rank can be aggregated to form a more incl... | https://en.wikipedia.org/wiki?curid=30463 |
19,211 | With advances in the theory, data and analytical technology of biological systematics, the Linnaean system has transformed into a system of modern biological classification intended to reflect the evolutionary relationships among organisms, both living and extinct. | https://en.wikipedia.org/wiki?curid=30463 |
19,212 | The exact definition of taxonomy varies from source to source, but the core of the discipline remains: the conception, naming, and classification of groups of organisms. As points of reference, recent definitions of taxonomy are presented below: | https://en.wikipedia.org/wiki?curid=30463 |
19,213 | The varied definitions either place taxonomy as a sub-area of systematics (definition 2), invert that relationship (definition 6), or appear to consider the two terms synonymous. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy (definitions 1 and 2), or a part of systema... | https://en.wikipedia.org/wiki?curid=30463 |
19,214 | In 1970 Michener "et al." defined "systematic biology" and "taxonomy" (terms that are often confused and used interchangeably) in relationship to one another as follows: | https://en.wikipedia.org/wiki?curid=30463 |
19,215 | Systematic biology (hereafter called simply systematics) is the field that (a) provides scientific names for organisms, (b) describes them, (c) preserves collections of them, (d) provides classifications for the organisms, keys for their identification, and data on their distributions, (e) investigates their evolutiona... | https://en.wikipedia.org/wiki?curid=30463 |
19,216 | A whole set of terms including taxonomy, systematic biology, systematics, biosystematics, scientific classification, biological classification, and phylogenetics have at times had overlapping meanings – sometimes the same, sometimes slightly different, but always related and intersecting. The broadest meaning of "taxon... | https://en.wikipedia.org/wiki?curid=30463 |
19,217 | while "classification" focuses on placing organisms within hierarchical groups that show their relationships to other organisms. | https://en.wikipedia.org/wiki?curid=30463 |
19,218 | A taxonomic revision or taxonomic review is a novel analysis of the variation patterns in a particular taxon. This analysis may be executed on the basis of any combination of the various available kinds of characters, such as morphological, anatomical, palynological, biochemical and genetic. A monograph or complete rev... | https://en.wikipedia.org/wiki?curid=30463 |
19,219 | Taxonomic characters are the taxonomic attributes that can be used to provide the evidence from which relationships (the phylogeny) between taxa are inferred. Kinds of taxonomic characters include: | https://en.wikipedia.org/wiki?curid=30463 |
19,220 | The term "alpha taxonomy" is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, and the products of research through the end of the 19th century. | https://en.wikipedia.org/wiki?curid=30463 |
19,221 | William Bertram Turrill introduced the term "alpha taxonomy" in a series of papers published in 1935 and 1937 in which he discussed the philosophy and possible future directions of the discipline of taxonomy. ... there is an increasing desire amongst taxonomists to consider their problems from wider viewpoints, to inve... | https://en.wikipedia.org/wiki?curid=30463 |
19,222 | Turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy. | https://en.wikipedia.org/wiki?curid=30463 |
19,223 | Later authors have used the term in a different sense, to mean the delimitation of species (not subspecies or taxa of other ranks), using whatever investigative techniques are available, and including sophisticated computational or laboratory techniques. Thus, Ernst Mayr in 1968 defined "beta taxonomy" as the classific... | https://en.wikipedia.org/wiki?curid=30463 |
19,224 | How species should be defined in a particular group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy. By extension, macrotaxonomy is the study of groups at the higher taxonomic r... | https://en.wikipedia.org/wiki?curid=30463 |
19,225 | While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, a truly scientific attempt to classify organisms did not occur until the 18th century. Earlier works were primarily descriptive and focused on plants that were useful in agriculture or medicine. There are a number of stages ... | https://en.wikipedia.org/wiki?curid=30463 |
19,226 | Naming and classifying human surroundings likely begun with the onset of language. Distinguishing poisonous plants from edible plants is integral to the survival of human communities. Medicinal plant illustrations show up in Egyptian wall paintings from c. 1500 BC, indicating that the uses of different species were und... | https://en.wikipedia.org/wiki?curid=30463 |
19,227 | Organisms were first classified by Aristotle (Greece, 384–322 BC) during his stay on the Island of Lesbos. He classified beings by their parts, or in modern terms "attributes", such as having live birth, having four legs, laying eggs, having blood, or being warm-bodied. He divided all living things into two groups: pla... | https://en.wikipedia.org/wiki?curid=30463 |
19,228 | Taxonomy in the Middle Ages was largely based on the Aristotelian system, with additions concerning the philosophical and existential order of creatures. This included concepts such as the great chain of being in the Western scholastic tradition, again deriving ultimately from Aristotle. The Aristotelian system did not... | https://en.wikipedia.org/wiki?curid=30463 |
19,229 | and taxonomic works became ambitious enough to replace the ancient texts. This is sometimes credited to the development of sophisticated optical lenses, which allowed the morphology of organisms to be studied in much greater detail. One of the earliest authors to take advantage of this leap in technology was the Italia... | https://en.wikipedia.org/wiki?curid=30463 |
19,230 | The Swedish botanist Carl Linnaeus (1707–1778) ushered in a new era of taxonomy. With his major works "Systema Naturae" 1st Edition in 1735, "Species Plantarum" in 1753, and "Systema Naturae" 10th Edition, he revolutionized modern taxonomy. His works implemented a standardized binomial naming system for animal and plan... | https://en.wikipedia.org/wiki?curid=30463 |
19,231 | A pattern of groups nested within groups was specified by Linnaeus' classifications of plants and animals, and these patterns began to be represented as dendrograms of the animal and plant kingdoms toward the end of the 18th century, well before Charles Darwin's "On the Origin of Species" was published. The pattern of ... | https://en.wikipedia.org/wiki?curid=30463 |
19,232 | With Darwin's theory, a general acceptance quickly appeared that a classification should reflect the Darwinian principle of common descent. Tree of life representations became popular in scientific works, with known fossil groups incorporated. One of the first modern groups tied to fossil ancestors was birds. Using the... | https://en.wikipedia.org/wiki?curid=30463 |
19,233 | The cladistic method has emerged since the 1960s. In 1958, Julian Huxley used the term "clade". Later, in 1960, Cain and Harrison introduced the term "cladistic". The salient feature is arranging taxa in a hierarchical evolutionary tree, with the desideratum that all named taxa are monophyletic. A taxon is called monop... | https://en.wikipedia.org/wiki?curid=30463 |
19,234 | Cladistic classifications are compatible with traditional Linnean taxonomy and the Codes of Zoological and Botanical nomenclature. An alternative system of nomenclature, the "International Code of Phylogenetic Nomenclature" or "PhyloCode" has been proposed, whose intent is to regulate the formal naming of clades. Linna... | https://en.wikipedia.org/wiki?curid=30463 |
19,235 | Well before discovery of Carl Linnaeus (Botanist) plants and animals were considered separate Kingdoms. Linnaeus used this as the top rank, dividing the physical world into the vegetable, animal and mineral kingdoms. As advances in microscopy made the classification of microorganisms possible, the number of kingdoms in... | https://en.wikipedia.org/wiki?curid=30463 |
19,236 | Domains are a relatively new grouping. First proposed in 1977, Carl Woese's three-domain system was not generally accepted until later. One main characteristic of the three-domain method is the separation of Archaea and Bacteria, previously grouped into the single kingdom Bacteria (a kingdom also sometimes called Moner... | https://en.wikipedia.org/wiki?curid=30463 |
19,237 | Thomas Cavalier-Smith, who published extensively on the classification of protists, in 2002 proposed that the Neomura, the clade that groups together the Archaea and Eucarya, would have evolved from Bacteria, more precisely from Actinomycetota. His 2004 classification treated the archaeobacteria as part of a subkingdom... | https://en.wikipedia.org/wiki?curid=30463 |
19,238 | Partial classifications exist for many individual groups of organisms and are revised and replaced as new information becomes available; however, comprehensive, published treatments of most or all life are rarer; recent examples are that of Adl et al., 2012 and 2019, which covers eukaryotes only with an emphasis on pro... | https://en.wikipedia.org/wiki?curid=30463 |
19,239 | Biological taxonomy is a sub-discipline of biology, and is generally practiced by biologists known as "taxonomists", though enthusiastic naturalists are also frequently involved in the publication of new taxa. Because taxonomy aims to describe and organize life, the work conducted by taxonomists is essential for the st... | https://en.wikipedia.org/wiki?curid=30463 |
19,240 | Biological classification is a critical component of the taxonomic process. As a result, it informs the user as to what the relatives of the taxon are hypothesized to be. Biological classification uses taxonomic ranks, including among others (in order from most inclusive to least inclusive): Domain, Kingdom, Phylum, Cl... | https://en.wikipedia.org/wiki?curid=30463 |
19,241 | The "definition" of a taxon is encapsulated by its description or its diagnosis or by both combined. There are no set rules governing the definition of taxa, but the naming and publication of new taxa is governed by sets of rules. In zoology, the nomenclature for the more commonly used ranks (superfamily to subspecies)... | https://en.wikipedia.org/wiki?curid=30463 |
19,242 | However, often much more information is included, like the geographic range of the taxon, ecological notes, chemistry, behavior, etc. How researchers arrive at their taxa varies: depending on the available data, and resources, methods vary from simple quantitative or qualitative comparisons of striking features, to ela... | https://en.wikipedia.org/wiki?curid=30463 |
19,243 | An "authority" may be placed after a scientific name. The authority is the name of the scientist or scientists who first validly published the name. For example, in 1758 Linnaeus gave the Asian elephant the scientific name "Elephas maximus", so the name is sometimes written as ""Elephas maximus" Linnaeus, 1758". The na... | https://en.wikipedia.org/wiki?curid=30463 |
19,244 | In phenetics, also known as taximetrics, or numerical taxonomy, organisms are classified based on overall similarity, regardless of their phylogeny or evolutionary relationships. It results in a measure of hypergeometric "distance" between taxa. Phenetic methods have become relatively rare in modern times, largely supe... | https://en.wikipedia.org/wiki?curid=30463 |
19,245 | Modern taxonomy uses database technologies to search and catalogue classifications and their documentation. While there is no commonly used database, there are comprehensive databases such as the "Catalogue of Life", which attempts to list every documented species. The catalogue listed 1.64 million species for all king... | https://en.wikipedia.org/wiki?curid=30463 |
19,246 | An octopus (: octopuses or octopodes, see below for variants) is a soft-bodied, eight-limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, an octopus is bilaterally symmetric with tw... | https://en.wikipedia.org/wiki?curid=22780 |
19,247 | Octopuses inhabit various regions of the ocean, including coral reefs, pelagic waters, and the seabed; some live in the intertidal zone and others at abyssal depths. Most species grow quickly, mature early, and are short-lived. In most species, the male uses a specially adapted arm to deliver a bundle of sperm directly... | https://en.wikipedia.org/wiki?curid=22780 |
19,248 | Octopuses appear in mythology as sea monsters like the Kraken of Norway and the Akkorokamui of the Ainu, and probably the Gorgon of ancient Greece. A battle with an octopus appears in Victor Hugo's book "Toilers of the Sea", inspiring other works such as Ian Fleming's "Octopussy". Octopuses appear in Japanese erotic ar... | https://en.wikipedia.org/wiki?curid=22780 |
19,249 | The scientific Latin term "octopus" was derived from Ancient Greek ὀκτώπους, a compound form of ὀκτώ ("oktō", "eight") and πούς ("pous", "foot"), itself a variant form of ὀκτάπους, a word used for example by Alexander of Tralles (c. 525–c. 605) for the common octopus. The standard pluralised form of "octopus" in Englis... | https://en.wikipedia.org/wiki?curid=22780 |
19,250 | Historically, the first plural to commonly appear in English language sources, in the early 19th century, is the latinate form "octopi", followed by the English form "octopuses" in the latter half of the same century. The Hellenic plural is roughly contemporary in usage, although it is also the rarest. | https://en.wikipedia.org/wiki?curid=22780 |
19,251 | "Fowler's Modern English Usage" states that the only acceptable plural in English is "octopuses", that "octopi" is misconceived, and "octopodes" pedantic; the last is nonetheless used frequently enough to be acknowledged by the descriptivist "Merriam-Webster 11th Collegiate Dictionary" and "Webster's New World College ... | https://en.wikipedia.org/wiki?curid=22780 |
19,252 | The giant Pacific octopus "(Enteroctopus dofleini)" is often cited as the largest known octopus species. Adults usually weigh around 15 kg (33 lb), with an arm span of up to 4.3 m (14 ft). The largest specimen of this species to be scientifically documented was an animal with a live mass of 71 kg (156.5 lb). Much large... | https://en.wikipedia.org/wiki?curid=22780 |
19,253 | The octopus is bilaterally symmetrical along its dorso-ventral (back to belly) axis; the head and foot are at one end of an elongated body and function as the anterior (front) of the animal. The head includes the mouth and brain. The foot has evolved into a set of flexible, prehensile appendages, known as "arms", that ... | https://en.wikipedia.org/wiki?curid=22780 |
19,254 | The skin consists of a thin outer epidermis with mucous cells and sensory cells, and a connective tissue dermis consisting largely of collagen fibres and various cells allowing colour change. Most of the body is made of soft tissue allowing it to lengthen, contract, and contort itself. The octopus can squeeze through t... | https://en.wikipedia.org/wiki?curid=22780 |
19,255 | The interior surfaces of the arms are covered with circular, adhesive suckers. The suckers allow the octopus to anchor itself or to manipulate objects. Each sucker is usually circular and bowl-like and has two distinct parts: an outer shallow cavity called an infundibulum and a central hollow cavity called an acetabulu... | https://en.wikipedia.org/wiki?curid=22780 |
19,256 | The eyes of the octopus are large and at the top of the head. They are similar in structure to those of a fish, and are enclosed in a cartilaginous capsule fused to the cranium. The cornea is formed from a translucent epidermal layer; the slit-shaped pupil forms a hole in the iris just behind the cornea. The lens is su... | https://en.wikipedia.org/wiki?curid=22780 |
19,257 | Some species differ in form from the typical octopus body shape. Basal species, the Cirrina, have stout gelatinous bodies with webbing that reaches near the tip of their arms, and two large fins above the eyes, supported by an internal shell. Fleshy papillae or cirri are found along the bottom of the arms, and the eyes... | https://en.wikipedia.org/wiki?curid=22780 |
19,258 | Octopuses have a closed circulatory system, in which the blood remains inside blood vessels. Octopuses have three hearts; a systemic or main heart that circulates blood around the body and two branchial or gill hearts that pump it through each of the two gills. The systemic heart is inactive when the animal is swimming... | https://en.wikipedia.org/wiki?curid=22780 |
19,259 | The systemic heart has muscular contractile walls and consists of a single ventricle and two atria, one for each side of the body. The blood vessels consist of arteries, capillaries and veins and are lined with a cellular endothelium which is quite unlike that of most other invertebrates. The blood circulates through t... | https://en.wikipedia.org/wiki?curid=22780 |
19,260 | Respiration involves drawing water into the mantle cavity through an aperture, passing it through the gills, and expelling it through the siphon. The ingress of water is achieved by contraction of radial muscles in the mantle wall, and flapper valves shut when strong circular muscles force the water out through the sip... | https://en.wikipedia.org/wiki?curid=22780 |
19,261 | The thin skin of the octopus absorbs additional oxygen. When resting, around 41% of an octopus's oxygen absorption is through the skin. This decreases to 33% when it swims, as more water flows over the gills; skin oxygen uptake also increases. When it is resting after a meal, absorption through the skin can drop to 3% ... | https://en.wikipedia.org/wiki?curid=22780 |
19,262 | The digestive system of the octopus begins with the buccal mass which consists of the mouth with its chitinous beak, the pharynx, radula and salivary glands. The radula is a spiked, muscular tongue-like organ with multiple rows of tiny teeth. Food is broken down and is forced into the oesophagus by two lateral extensio... | https://en.wikipedia.org/wiki?curid=22780 |
19,263 | During osmoregulation, fluid is added to the pericardia of the branchial hearts. The octopus has two nephridia (equivalent to vertebrate kidneys) which are associated with the branchial hearts; these and their associated ducts connect the pericardial cavities with the mantle cavity. Before reaching the branchial heart,... | https://en.wikipedia.org/wiki?curid=22780 |
19,264 | Octopuses (along with cuttlefish) have the highest brain-to-body mass ratios of all invertebrates; this is greater than that of many vertebrates. Octopuses have the same jumping genes that are active in the human brain, implying an evolutionary convergence at molecular level. The nervous system is complex, only part of... | https://en.wikipedia.org/wiki?curid=22780 |
19,265 | Like other cephalopods, octopuses have camera-like eyes, and can distinguish the polarisation of light. Colour vision appears to vary from species to species, for example being present in "O. aegina" but absent in "O. vulgaris". | https://en.wikipedia.org/wiki?curid=22780 |
19,266 | Opsins in the skin respond to different wavelengths of light and help the animals choose a coloration that camouflages them; the chromatophores in the skin can respond to light independently of the eyes. | https://en.wikipedia.org/wiki?curid=22780 |
19,267 | An alternative hypothesis is that cephalopod eyes in species which only have a single photoreceptor protein may use chromatic aberration to turn monochromatic vision into colour vision, though this sacrifices image quality. This would explain pupils shaped like the letter U, the letter W, or a dumbbell, as well as expl... | https://en.wikipedia.org/wiki?curid=22780 |
19,268 | Attached to the brain are two organs called statocysts (sac-like structures containing a mineralised mass and sensitive hairs), that allow the octopus to sense the orientation of its body. They provide information on the position of the body relative to gravity and can detect angular acceleration. An autonomic response... | https://en.wikipedia.org/wiki?curid=22780 |
19,269 | Octopuses have an excellent somatosensory system. Their suction cups are equipped with chemoreceptors so they can taste what they touch. Octopus arms move easily because the sensors recognise octopus skin and prevent self-attachment. Octopuses appear to have poor proprioceptive sense and must observe the arms visually ... | https://en.wikipedia.org/wiki?curid=22780 |
19,270 | The ink sac of an octopus is located under the digestive gland. A gland attached to the sac produces the ink, and the sac stores it. The sac is close enough to the funnel for the octopus to shoot out the ink with a water jet. Before it leaves the funnel, the ink passes through glands which mix it with mucus, creating a... | https://en.wikipedia.org/wiki?curid=22780 |
19,271 | Octopuses are gonochoric and have a single, posteriorly-located gonad which is associated with the coelom. The testis in males and the ovary in females bulges into the gonocoel and the gametes are released here. The gonocoel is connected by the gonoduct to the mantle cavity, which it enters at the gonopore. An optic gl... | https://en.wikipedia.org/wiki?curid=22780 |
19,272 | When octopuses reproduce, the male uses a specialised arm called a hectocotylus to transfer spermatophores (packets of sperm) from the terminal organ of the reproductive tract (the cephalopod "penis") into the female's mantle cavity. The hectocotylus in benthic octopuses is usually the third right arm, which has a spoo... | https://en.wikipedia.org/wiki?curid=22780 |
19,273 | The reproduction of octopuses has been studied in only a few species. One such species is the giant Pacific octopus, in which courtship is accompanied, especially in the male, by changes in skin texture and colour. The male may cling to the top or side of the female or position himself beside her. There is some specula... | https://en.wikipedia.org/wiki?curid=22780 |
19,274 | About forty days after mating, the female giant Pacific octopus attaches strings of small fertilised eggs (10,000 to 70,000 in total) to rocks in a crevice or under an overhang. Here she guards and cares for them for about five months (160 days) until they hatch. In colder waters, such as those off Alaska, it may take ... | https://en.wikipedia.org/wiki?curid=22780 |
19,275 | The eggs have large yolks; cleavage (division) is superficial and a germinal disc develops at the pole. During gastrulation, the margins of this grow down and surround the yolk, forming a yolk sac, which eventually forms part of the gut. The dorsal side of the disc grows upward and forms the embryo, with a shell gland ... | https://en.wikipedia.org/wiki?curid=22780 |
19,276 | Most young octopuses hatch as paralarvae and are planktonic for weeks to months, depending on the species and water temperature. They feed on copepods, arthropod larvae and other zooplankton, eventually settling on the ocean floor and developing directly into adults with no distinct metamorphoses that are present in ot... | https://en.wikipedia.org/wiki?curid=22780 |
19,277 | In the argonaut (paper nautilus), the female secretes a fine, fluted, papery shell in which the eggs are deposited and in which she also resides while floating in mid-ocean. In this she broods the young, and it also serves as a buoyancy aid allowing her to adjust her depth. The male argonaut is minute by comparison and... | https://en.wikipedia.org/wiki?curid=22780 |
19,278 | Octopuses have a relatively short lifespan; some species live for as little as six months. The Giant Pacific octopus, one of the two largest species of octopus, may live for as much as five years. Octopus lifespan is limited by reproduction. For most octopuses the last stage of their life is called senescence. It is th... | https://en.wikipedia.org/wiki?curid=22780 |
19,279 | Octopus reproductive organs mature due to the hormonal influence of the optic gland but result in the inactivation of their digestive glands. Unable to feed, the octopus typically dies of starvation. Experimental removal of both optic glands after spawning was found to result in the cessation of broodiness, the resumpt... | https://en.wikipedia.org/wiki?curid=22780 |
19,280 | Octopuses live in every ocean, and different species have adapted to different marine habitats. As juveniles, common octopuses inhabit shallow tide pools. The Hawaiian day octopus ("Octopus cyanea") lives on coral reefs; argonauts drift in pelagic waters. "Abdopus aculeatus" mostly lives in near-shore seagrass beds. So... | https://en.wikipedia.org/wiki?curid=22780 |
19,281 | Most species are solitary when not mating, though a few are known to occur in high densities and with frequent interactions, signaling, mate defending and eviction of individuals from dens. This is likely the result of abundant food supplies combined with limited den sites. The LPSO has been described as particularly s... | https://en.wikipedia.org/wiki?curid=22780 |
19,282 | Octopuses bring captured prey to the den, where they can eat it safely. Sometimes the octopus catches more prey than it can eat, and the den is often surrounded by a midden of dead and uneaten food items. Other creatures, such as fish, crabs, molluscs and echinoderms, often share the den with the octopus, either becaus... | https://en.wikipedia.org/wiki?curid=22780 |
19,283 | Nearly all octopuses are predatory; bottom-dwelling octopuses eat mainly crustaceans, polychaete worms, and other molluscs such as whelks and clams; open-ocean octopuses eat mainly prawns, fish and other cephalopods. Major items in the diet of the giant Pacific octopus include bivalve molluscs such as the cockle "Clino... | https://en.wikipedia.org/wiki?curid=22780 |
19,284 | A benthic (bottom-dwelling) octopus typically moves among the rocks and feels through the crevices. The creature may make a jet-propelled pounce on prey and pull it toward the mouth with its arms, the suckers restraining it. Small prey may be completely trapped by the webbed structure. Octopuses usually inject crustace... | https://en.wikipedia.org/wiki?curid=22780 |
19,285 | Some species have other modes of feeding. "Grimpoteuthis" has a reduced or non-existent radula and swallows prey whole. In the deep-sea genus "Stauroteuthis", some of the muscle cells that control the suckers in most species have been replaced with photophores which are believed to fool prey by directing them to the mo... | https://en.wikipedia.org/wiki?curid=22780 |
19,286 | Octopuses mainly move about by relatively slow crawling with some swimming in a head-first position. Jet propulsion or backward swimming, is their fastest means of locomotion, followed by swimming and crawling. When in no hurry, they usually crawl on either solid or soft surfaces. Several arms are extended forward, som... | https://en.wikipedia.org/wiki?curid=22780 |
19,287 | Most octopuses swim by expelling a jet of water from the mantle through the siphon into the sea. The physical principle behind this is that the force required to accelerate the water through the orifice produces a reaction that propels the octopus in the opposite direction. The direction of travel depends on the orient... | https://en.wikipedia.org/wiki?curid=22780 |
19,288 | Cirrate octopuses cannot produce jet propulsion and rely on their fins for swimming. They have neutral buoyancy and drift through the water with the fins extended. They can also contract their arms and surrounding web to make sudden moves known as "take-offs". Another form of locomotion is "pumping", which involves sym... | https://en.wikipedia.org/wiki?curid=22780 |
19,289 | In 2005, "Adopus aculeatus" and veined octopus ("Amphioctopus marginatus") were found to walk on two arms, while at the same time mimicking plant matter. This form of locomotion allows these octopuses to move quickly away from a potential predator without being recognised. Some species of octopus can crawl out of the w... | https://en.wikipedia.org/wiki?curid=22780 |
19,290 | Octopuses are highly intelligent. Maze and problem-solving experiments have shown evidence of a memory system that can store both short- and long-term memory. Young octopuses learn nothing from their parents, as adults provide no parental care beyond tending to their eggs until the young octopuses hatch. | https://en.wikipedia.org/wiki?curid=22780 |
19,291 | In laboratory experiments, octopuses can readily be trained to distinguish between different shapes and patterns. They have been reported to practise observational learning, although the validity of these findings is contested. Octopuses have also been observed in what has been described as play: repeatedly releasing b... | https://en.wikipedia.org/wiki?curid=22780 |
19,292 | Octopuses use camouflage when hunting and to avoid predators. To do this they use specialised skin cells which change the appearance of the skin by adjusting its colour, opacity, or reflectivity. Chromatophores contain yellow, orange, red, brown, or black pigments; most species have three of these colours, while some h... | https://en.wikipedia.org/wiki?curid=22780 |
19,293 | Octopuses can create distracting patterns with waves of dark coloration across the body, a display known as the "passing cloud". Muscles in the skin change the texture of the mantle to achieve greater camouflage. In some species, the mantle can take on the spiky appearance of algae; in others, skin anatomy is limited t... | https://en.wikipedia.org/wiki?curid=22780 |
19,294 | A "moving rock" trick involves the octopus mimicking a rock and then inching across the open space with a speed matching that of the surrounding water. | https://en.wikipedia.org/wiki?curid=22780 |
19,295 | Aside from humans, octopuses may be preyed on by fishes, seabirds, sea otters, pinnipeds, cetaceans, and other cephalopods. Octopuses typically hide or disguise themselves by camouflage and mimicry; some have conspicuous warning coloration (aposematism) or deimatic behaviour. An octopus may spend 40% of its time hidden... | https://en.wikipedia.org/wiki?curid=22780 |
19,296 | Once they have been seen by a predator, they commonly try to escape but can also use distraction with an ink cloud ejected from the ink sac. The ink is thought to reduce the efficiency of olfactory organs, which would aid evasion from predators that employ smell for hunting, such as sharks. Ink clouds of some species m... | https://en.wikipedia.org/wiki?curid=22780 |
19,297 | When under attack, some octopuses can perform arm autotomy, in a manner similar to the way skinks and other lizards detach their tails. The crawling arm may distract would-be predators. Such severed arms remain sensitive to stimuli and move away from unpleasant sensations. Octopuses can replace lost limbs. | https://en.wikipedia.org/wiki?curid=22780 |
19,298 | Some octopuses, such as the mimic octopus, can combine their highly flexible bodies with their colour-changing ability to mimic other, more dangerous animals, such as lionfish, sea snakes, and eels. | https://en.wikipedia.org/wiki?curid=22780 |
19,299 | The diseases and parasites that affect octopuses have been little studied, but cephalopods are known to be the intermediate or final hosts of various parasitic cestodes, nematodes and copepods; 150 species of protistan and metazoan parasites have been recognised. The Dicyemidae are a family of tiny worms that are found... | https://en.wikipedia.org/wiki?curid=22780 |
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