Squid are marine Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology. As a noun it can be a term for a certain kind of navy, or those enlisted in such a navy cephalopods A cephalopod (Greek plural Κεφαλόποδα ; "head-feet") is any member of the mollusc class Cephalopoda, characterized by bilateral body symmetry, a prominent head, and a modification of the mollusc foot, a muscular hydrostat, into the form of arms or tentacles. Teuthology, a branch of malacology, is the study of cephalopods. These of the order The Latin suffix -formes meaning "having the form of" is used for the scientific name of orders of birds and fishes, but not for those of mammals and invertebrates Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry Symmetry in biology is the balanced distribution of duplicate body parts or shapes. The body plans of most multicellular organisms exhibit some form of symmetry, either radial symmetry or bilateral symmetry or "spherical symmetry". A small minority exhibit no symmetry, a mantle The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself, and arms By definition, cephalopod arms have suckers along most of their length, as opposed to tentacles, which have suckers only near their ends.[citation needed]. Squid, like cuttlefish Cuttlefish are marine animals of the order Sepiida. They belong to the class Cephalopoda . Despite their name, cuttlefish are not fish but molluscs. Recent studies indicate that cuttlefish are among the most intelligent invertebrates. Cuttlefish also have one of the largest brain-to-body size ratios of all invertebrates, have eight arms By definition, cephalopod arms have suckers along most of their length, as opposed to tentacles, which have suckers only near their ends.[citation needed] arranged in pairs and two longer tentacles A tentacle or bothrium is one of usually two or more elongated flexible organs present in animals, especially invertebrates. The term may also refer to the hairs of the leaves of some insectivorous plants. Usually, tentacles are used for feeding, feeling and grasping. Anatomically, they work like other muscular hydrostats. (The only known exception is the bigfin squid The bigfin squids are a group of rarely seen cephalopods with a very distinctive morphology. They are placed in the genus Magnapinna and family Magnapinnidae. The family is known only from larval, paralarval, and juvenile specimens, but some authorities believe the adult creature has been seen: Several videos have been taken of animals nicknamed group, which have ten very long, thin arms of equal length.) Squid are strong swimmers and certain species can 'fly' for short distances out of the water.[2]
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Modification from ancestral forms
Squid have differentiated from their ancestral molluscs The Mollusca, common name molluscs or mollusks,[note 1] is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. This is the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats. Molluscs are highly diverse, such that the body plan has been condensed antero-posteriorly and extended dorso-ventrally. What before may have been the foot The foot is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made up of one or more segments or bones, generally including claws or nails of the ancestor is modified into a complex set of tentacles and highly developed sense organs, including advanced eyes similar to those of vertebrates Vertebrates are members of the subphylum Vertebrata, chordates with backbones and spinal columns. About 58,000 species of vertebrates have been currently described. Vertebrata is the largest subphylum of chordates, and contains many familiar groups of large land animals. Vertebrates are comprised of animals from the groups jawless fishs, bony fish,.
The ancestral shell has been lost, with only an internal gladius, or pen, remaining. The pen is a feather-shaped internal structure that supports the squid's mantle The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself and serves as a site for muscle attachment. It is made of a chitin Chitin n (pronounced /ˈkaɪtɨn/) is a long-chain polymer of a N-acetylglucosamine, a derivative of glucose, and is found in many places throughout the natural world. It is the main component of the cell walls of fungi, the exoskeletons of arthropods such as crustaceans (e.g. crabs, lobsters and shrimps) and insects, the radulas of mollusks and-like substance.
Anatomy
European Squid (Loligo vulgaris)The main body mass is enclosed in the mantle The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself, which has a swimming fin along each side. These fins, unlike in other marine organisms, are not the main source of locomotion in most species.
The skin is covered in chromatophores Chromatophores are pigment-containing and light-reflecting cells found in amphibians, fish, reptiles, crustaceans, and cephalopods. They are largely responsible for generating skin and eye colour in cold-blooded animals and are generated in the neural crest during embryonic development. Mature chromatophores are grouped into subclasses based on, which enable the squid to change color to suit its surroundings, making it effectively invisible Invisibility is the state of an object that cannot be seen. An object in this state is said to be Invisible . The term is usually used as a fantasy/science fiction term, where objects are literally made unseeable by magical or technological means; however, its effects can also be seen in the real world, particularly in physics and perceptional. The underside is also almost always lighter than the topside, to provide camouflage Camouflage is a method of crypsis—avoidance of observation—that allows an otherwise visible organism or object to remain indiscernible from the surrounding environment through deception. Examples include a tiger's stripes, the battledress of a modern soldier and a butterfly camouflaging itself as a leaf. The theory of camouflage covers the from both prey and predator.
Under the body are openings to the mantle cavity, which contains the gills A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist. The microscopic structure of a gill presents a large surface area to the external (ctenidia) and openings to the excretory and reproductive systems The reproductive system or genital system is a system of organs within an organism which work together for the purpose of reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system. Unlike most organ systems, the sexes of differentiated species often have significant. At the front of the mantle cavity lies the siphon, which the squid uses for locomotion via precise jet propulsion A jet engine is a reaction engine that discharges a fast moving jet of fluid to generate thrust in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets and pump-jets. In general, most jet engines are internal combustion engines but non-combusting forms also exist. In this form of locomotion, water is sucked into the mantle cavity and expelled out of the siphon in a fast, strong jet. The direction of the siphon can be changed, to suit the direction of travel.
Inside the mantle cavity, beyond the siphon, lies the visceral mass, which is covered by a thin, membranous epidermis In anatomy, squamous epithelium is an epithelium characterised by its most superficial layer consisting of flat, scale-like cells called squamous cell. Epithelium may possess only one layer of these cells, in which case it is referred to as simple squamous epithelium; or it may possess multiple layers, referred to then as stratified squamous. Under this are all the major internal organs.
Nervous system
The giant axon The squid giant axon is the very large axon that controls part of the water jet propulsion system in squid. It was discovered by English zoologist and neurophysiologist John Zachary Young in 1936. Squid use this system primarily for making brief but very fast movements through the water, which may be up to 1 mm (0.04 inches) in diameter in some larger species, innervates A peripheral nerve, or simply nerve is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system. In the central nervous system, the analogous structures are known as tracts the mantle and controls part of the jet propulsion system.
As cephalopods, squid exhibit relatively high intelligence among invertebrates. For example, groups of Humboldt squid hunt cooperatively, using active communication. (See Cephalopod intelligence Cephalopod intelligence has an important comparative aspect in our understanding of intelligence, because it relies on a nervous system fundamentally different from that of vertebrates. The cephalopod class of mollusks, particularly the Coleoidea subclass , are considered the most intelligent invertebrates and an important example of advanced.)
Reproductive system
| A dissected male specimen of Onykia ingens, showing a non-erect penis (the white tubular structure located below most of the other organs) A specimen of the same species exhibiting elongation of the penis to 67 cm in length |
In females the ink sac With the exception of nocturnal and very deep water cephalopods, all coeloids which dwell in light conditions have an ink sac, which can be used to expel a cloud of dark ink to confuse predators. This sac is a muscular bag which originated as an extension of the hind gut. It lies beneath the gut and opens into the anus, into which its contents – is hidden from view by a pair of white nidamental glands, which lie anterior to the gills. There are also red-spotted accessory nidamental glands. Both organs are associated with food manufacture and shells for the eggs. Females also have a large translucent ovary The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in females are homologous to testes in males, in that they are both gonads and endocrine glands, situated towards the posterior of the visceral mass.
Males do not possess these organs, but instead have a large testis The testicle is the male generative gland in animals in place of the ovary, and a spermatophoric gland and sac. In mature males, this sac may contain spermatophores A spermatophore is a capsule or mass created by males of various animal species, containing spermatozoa and transferred in entirety to the female's ovipore during copulation. It may contain nourishment for the female, in which case it is called a nuptial gift, although in many species the "gift" provides little nutrient value . The, which are placed inside the female's mantle during mating.
Shallow water species of the continental shelf The continental shelf is the extended perimeter of each continent and associated coastal plain, and was part of the continent during the glacial periods, but is undersea during interglacial periods such as the current epoch by relatively shallow seas and gulfs and epipelagic Any water in the sea that is not close to the bottom or near to the shore is in the pelagic zone. The word pelagic comes from the Greek πέλαγος or pélagos, which means "open sea." The pelagic zone can be thought of in terms of an imaginary cylinder or water column that goes from the surface of the sea almost to the bottom, as/mesopelagic The mesopelagic (also known as the middle pelagic or twilight zone) is a pelagic zone extending from 200 m (650 ft.) down to around 1000 m (3280 ft.) below sea level. It is located between the photic epipelagic and the aphotic bathypelagic, where there is no light at all. Although some light penetrates this deep, it is insufficient for zones are characterised by the presence of hectocotyli, specially modified arms used to fertilise the female's eggs.[3] Most deep sea squid lack hectocotyli and have longer penises; Ancistrocheiridae and Cranchiinae are exceptions.[3] Giant squid The giant squid is a deep-ocean dwelling squid in the family Architeuthidae, represented by as many as eight species. Giant squid can grow to a tremendous size: recent estimates put the maximum size at 13 metres (43 ft) for females and 10 metres (33 ft) for males from caudal fin to the tip of the two long tentacles (second only to the colossal of the genus Architeuthis are unusual in that they possess both a large penis and modified arm tips, although it is uncertain whether the latter are used for spermatophore transfer.[3] Penis elongation has been observed in the deep water species Onykia ingens; when erect, the penis may be as long as the mantle, head and arms combined.[3][4] As such, deep water squid have the greatest known penis length relative to body size of all mobile animals, second in the entire animal kingdom only to certain sessile barnacles A barnacle is a type of arthropod belonging to infraclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile suspension feeders, and have two nektonic larval stages. Around 1,220 barnacle.[3]
Digestive system
Like all cephalopods, squid have complex digestive systems. The muscular stomach In some animals, including vertebrates, echinoderms, insects and molluscs, the stomach is a muscular, hollow, dilated part of the alimentary canal which functions as the primary organ of the digestive tract. It is involved in the second phase of digestion, following mastication (chewing). The stomach is located between the esophagus and the small is found roughly in the midpoint of the visceral mass. From there, the bolus moves into the caecum The cecum or caecum is a pouch, connecting the ileum with the ascending colon of the large intestine. It is separated from the ileum by the ileocecal valve (ICV) or Bauhin's valve, and is considered to be the beginning of the large intestine. It is also separated from the colon by the cecocolic junction. The appendix is connected to the cecum for digestion. The caecum, a long, white organ, is found next to the ovary or testis. In mature squid, more priority is given to reproduction such that the stomach and caecum often shrivel up during the later life stages. Finally, food goes to the liver The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion. The liver is necessary for survival; there is currently no way to compensate for the absence of liver function (or digestive gland), found at the siphon end, for absorption. Solid waste is passed out of the rectum The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long.[citation needed] Its caliber is similar to that of the sigmoid colon at its commencement, but it is dilated near its termination, forming the rectal ampulla. Beside the rectum is the ink sac, which allows a squid to rapidly discharge black ink into the mantle cavity.
Ventral view of the viscera of the female Chtenopteryx siculaCardiovascular system
Squid have three hearts The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions. The term cardiac (as in cardiology) means "related to the heart" and comes from the Greek καρδιά, kardia, for "heart". Two brachial hearts feed the gills, each surrounding the larger systemic heart that pumps blood around the body. Squid blood contains the copper Copper is a chemical element with the symbol Cu (Latin: cuprum) and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is rather soft and malleable, and a freshly exposed surface has a pinkish or peachy color. It is used as a thermal conductor, an electrical conductor, a building material, and a-rich protein Proteins are organic compounds made of amino acids arranged in a linear chain and folded into a globular form. The amino acids in a polymer are joined together by the peptide bonds between the carboxyl and amino groups of adjacent amino acid residues. The sequence of amino acids in a protein is defined by the sequence of a gene, which is encoded hemocyanin Hemocyanins are respiratory proteins in the form of metalloproteins containing two copper atoms that reversibly bind a single oxygen molecule (O2). Oxygenation causes a color change between the colorless Cu(I) deoxygenated form and the blue Cu(II) oxygenated form. Hemocyanins carry oxygen in the hemolymph of most molluscs, and some arthropods, for transporting oxygen Oxygen (pronounced /ˈɒksɨdʒɨn/, OK-si-jin, from the Greek roots ὀξύς (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter), is the element with atomic number 8 and represented by the symbol O. It is a member of the chalcogen group on the periodic table, and is a highly. The faintly greenish hearts are surrounded by the renal sacs - the main excretory system. The kidneys The kidneys are paired organs with several functions. They are seen in many types of animals, including vertebrates and some invertebrates. They are an essential part of the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid-base balance, and regulation of blood pressure. They serve the are difficult to identify and stretch from the hearts (located at the posterior side of the ink sac) to the liver. The systemic heart is made of three chambers, a lower ventricle In the heart, a ventricle is a chamber which collects blood from an atrium and pumps it out of the heart, common reference systole. Interventricular means between two or more ventricles (for example the interventricular septum), while intraventricular means within one ventricle (for example an intraventricular block) and two upper auricles.
Head
The head end bears 8 arms and 2 tentacles (species in the bigfin squid The bigfin squids are a group of rarely seen cephalopods with a very distinctive morphology. They are placed in the genus Magnapinna and family Magnapinnidae. The family is known only from larval, paralarval, and juvenile specimens, but some authorities believe the adult creature has been seen: Several videos have been taken of animals nicknamed group have 10 identical arms), each a form of muscular hydrostat A muscular hydrostat is a biological structure found in animals. It is used to manipulate items or to move its host about and consists mainly of muscles with no skeletal support. It performs its hydraulic movement without fluid in a separate compartment, as in a hydrostatic skeleton. The principle behind the hydrostatic skeleton is that water is containing many suckers along the edge. These tentacles do not grow back if severed. In the mature male, one basal half of the left ventral tentacle is hectocotylised A hectocotylus is one of the arms of the male of most kinds of cephalopods that is modified in various ways to affect the fertilization of the female's eggs. It is a specialized, extended tentacle used to store spermatophores, the male gamete. Males generally form a new hectocotylus in each new season — and ends in a copulatory pad rather than suckers. It is used for intercourse.
The mouth is equipped with a sharp horny beak mainly made of chitin Chitin n (pronounced /ˈkaɪtɨn/) is a long-chain polymer of a N-acetylglucosamine, a derivative of glucose, and is found in many places throughout the natural world. It is the main component of the cell walls of fungi, the exoskeletons of arthropods such as crustaceans (e.g. crabs, lobsters and shrimps) and insects, the radulas of mollusks and[5] and cross-linked proteins, and is used to kill and tear prey into manageable pieces. The beak is very robust, but does not contain minerals, unlike the teeth and jaws of many other organisms, including marine species.[6] Captured whales often have indigestible squid beaks in their stomachs. The mouth contains the radula (the rough tongue common to all molluscs except bivalvia and aplacophora).
The eyes, on either side of the head, each contain a hard lens. The lens is focused through movement, much like the lens of a camera or telescope, rather than changing shape as the lens in the human eye does.
Squids appear to have limited hearing.[7]
Size
Giant squid in Melbourne Aquarium See also: Giant squid, Colossal Squid, and Cephalopod sizeThe majority are no more than 60 centimetres (24 in) long, although the giant squid may reach 13 metres (43 ft).[8]
In 1978, sharp, curved claws on the suction cups of squid tentacles cut up the rubber coating on the hull of the USS Stein. The size suggested the largest squid known at the time.[9]
In 2003, a large specimen of an abundant[10] but poorly understood species, Mesonychoteuthis hamiltoni (the Colossal Squid), was discovered. This species may grow to 14 metres (46 ft) in length, making it the largest invertebrate.[11] Squid have the largest eyes in the animal kingdom. Giant squid are featured in literature and folklore with a frightening connotation. The Kraken is a legendary tentacled monster possibly based on sightings of real giant squid.
In February 2007, a New Zealand fishing vessel caught a Colossal Squid weighing 495 kilograms (1,090 lb) and measuring around 10 metres (33 ft) off the coast of Antarctica.[12] This specimen represents the largest cephalopod to ever be scientifically documented.
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Fri, 13 Aug 2010 20:13:37 GMT+00:00
leads to outbreak of gawkers Guelph Mercury According to news reports, a three-and-a-half-metre long squid was found on the beach last Saturday morning. Residents rushed to the shore, anxious to gawk ...
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Chemists at the University of Otago have patented a gel derived from the squid which they claim can help to reduce both bleeding as well as scarring during a surgery It was revealed by
Connie
Fri, 27 Aug 2010 07:00:00 GM
If you like calamares or any dish with . squid. for that matter, then, knowing how to clean fresh whole . squid. would be very useful. Here's an illustration.
