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92-470: The most noticeable feature of the small town is a convent and affiliated care facility for the disabled. The convent and church have large gardens. The services are very beautiful, and include special blessings for travelers and pilgrims. The convent is known for its hospitality, running an albergue (pilgrim's shelter), including a donativo (donation suggested) meal. They are also one of the primary sources of pilgrim's shells for people walking this route of

184-760: A diploid sporophyte and haploid gametophyte stage. The haploid phase begins when the mature organism releases many spores, which then germinate to become male or female gametophytes. Sexual reproduction then results in the beginning of the diploid sporophyte stage, which will develop into a mature individual. The parenchymatous thalli are generally covered with a mucilage layer, rather than cuticle. Seaweed were generally considered homologues of terrestrial plants , but are only very distantly related to plants, and have evolved plant-like structures through convergent evolution . Where plants have leaves, stems, and reproductive organs, kelp have independently evolved blades, stipes, and sporangia . With radiometric dating and

276-449: A detectable difference in anaerobic energy expenditure than those without encrustation. In the absence of barnacle encrustation, individual scallops swim significantly longer, travel further, and attain greater elevation. The family name Pectinidae, which is based on the name of the type genus, Pecten , comes from the Latin pecten meaning comb , in reference to a comb-like structure of

368-456: A food additive, it may be used to reduce fat absorption and thus obesity. Kelp in its natural form has not yet been demonstrated to have such effects. Kelp's rich iron content can help prevent iron deficiency. Commercial production of kelp harvested from its natural habitat has taken place in Japan for over a century. Many countries today produce and consume laminaria products; the largest producer

460-753: A genetic plasticity for blade shapes for different water flow habitats. So individuals of the same species will have differences to other individuals of the same species due to what habitat they grow in. Many species have different morphologies for different wave disturbance regimes but giant kelp Macrocystis integrifolia has been found to have plasticity allowing for 4 distinct types of blade morphology depending on habitat. Where many species only have two or three different blade shapes for maximizing efficiency in only two or three habitats. These different blade shapes were found to decrease breakage and increase ability to photosynthesize . Blade adaptations like these are how kelp have evolved for efficiency in structure in

552-481: A given animal is "facing" requires detailed information about its valves. The model scallop shell consists of two similarly shaped valves with a straight hinge line along the top, devoid of teeth, and producing a pair of flat wings or "ears" (sometimes called "auricles", though this is also the term for two chambers in its heart) on either side of its midpoint, a feature which is unique to and apparent in all adult scallops. These ears may be of similar size and shape, or

644-511: A linear dispersal corridor entirely at sea level, with few obstacles to maritime peoples. Archaeological evidence from California's Channel Islands confirms that islanders were harvesting kelp forest shellfish and fish, beginning as much as 12,000 years ago. During the Highland Clearances , many Scottish Highlanders were moved on to areas of estates known as crofts , and went to industries such as fishing and kelping (producing soda ash from

736-526: A physical barrier around byssal openings to prevent sea stars from inserting their digestive membranes. Sponge encrustation protects C. hastata from barnacle larvae settlement, serving as a protection from epibionts that increase susceptibility to predators. Thus, barnacle larvae settlement occurs more frequently on sponge-free shells than on sponge-encrusted shells. In fact, barnacle encrustation negatively influences swimming in C. hastata . Those swimming with barnacle encrustation require more energy and show

828-523: A popular object to collect among beachcombers and vacationers. The shells also have a significant place in popular culture. Scallops inhabit all the oceans of the world, with the largest number of species living in the Indo-Pacific region. Most species live in relatively shallow waters from the low tide line to 100 m, while others prefer much deeper water. Although some species only live in very narrow environments, most are opportunistic and can live under

920-401: A row before becoming completely exhausted and requiring several hours of rest. Should a swimming scallop land on its left side, it is capable of flipping itself over to its right side via a similar shell-clapping movement called the righting reflex. So-called singing scallops are rumored to make an audible, soft popping sound as they flap their shells underwater (though whether or not this happens

1012-404: A savory garnish ( tororo konbu ) for rice and other dishes, as a vegetable, and a primary ingredient in popular snacks (such as tsukudani ). Transparent sheets of kelp ( oboro konbu ) are used as an edible decorative wrapping for rice and other foods. Kombu can be used to soften beans during cooking, and to help convert indigestible sugars and thus reduce flatulence. In Russia, especially in

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1104-533: A study done with genomic analysis . Studies of kelp structure evolution have helped in the understanding of the adaptations that have allowed for kelp to not only be extremely successful as a group of organisms but also successful as an ecosystem engineer of kelp forests , some of the most diverse and dynamic ecosystems on earth. Species of Laminaria in the British Isles; Species of Laminaria worldwide, listing of species at AlgaeBase : Other species in

1196-412: A turbulent ocean environment, to the point where their stability can shape entire habitats. Apart from these structural adaptations, the evolution of dispersal methods relating to structure have been important for the success of kelp as well. Kelp have had to adapt dispersal methods that can make successful use of ocean currents . Buoyancy of certain kelp structures allows for species to disperse with

1288-557: A vital defense mechanism for avoiding predators. Though rather weak, their series of eyes can detect surrounding movement and alert precaution in the presence of predators, most commonly sea stars, crabs, and snails. Physiological fitness and exercise of scallops decrease with age due to the decline of cellular and especially mitochondrial function, thus increasing the risk of capture and lowering rates of survival. Older individuals show lower mitochondrial volume density and aerobic capacity, as well as decreased anaerobic capacity construed from

1380-431: A wave disturbance gradient, many of these convergently evolved traits for structural reinforcement also correlate with distribution along that gradient. The wave disturbance gradient that this study refers to is the environments that this kelp inhabit have a varied level of perturbation from the tide and waves that pull at the kelp. It can be assumed from these results that niche partitioning along wave disturbance gradients

1472-456: A wide variety of conditions. Scallops can be found living within, upon, or under either rocks, coral, rubble, sea grass , kelp , sand, or mud. Most scallops begin their lives as byssally attached juveniles, an ability that some retain throughout their lives while others grow into free-living adults. Very little variation occurs in the internal arrangement of organs and systems within the scallop family, and what follows can be taken to apply to

1564-606: Is China. Laminaria japonica , the important commercial seaweed, was first introduced into China in the late 1920s from Hokkaido, Japan. Yet mariculture of this alga on a very large commercial scale was realized in China only in the 1950s. Between the 1950s and the 1980s, kelp production in China increased from about 60 to over 250,000 dry weight metric tons annually. Some of the earliest evidence for human use of marine resources, coming from Middle Stone Age sites in South Africa, includes

1656-514: Is a characteristic that has evolved within the lineage. In a 2008 paper, Puslednik et al. identified considerable convergence of shell morphology in a subset species of gliding Pectinidae, which suggests iterative morphological evolution may be more prevalent in the family than previously believed. There have been a number of efforts to address phylogenetic studies. Only three have assessed more than ten species and only one has included multiple outgroups. Nearly all previous molecular analyses of

1748-551: Is a key driver of divergence between closely related kelp. Due to the often varied and turbulent habitat that kelp inhabit, plasticity of certain structural traits has been a key for the evolutionary history of the phyla. Plasticity helps with a very important aspect of kelp adaptations to ocean environments, and that is the unusually high levels of morphological homoplasy between lineages. This in fact has made classifying brown algae difficult. Kelp often have similar morphological features to other species within its own area since

1840-526: Is based on molecular phylogeny using mitochondrial (12S, 16S) and nuclear (18S, 28S, and H3) gene markers by Yaron Malkowsky and Annette Klussmann-Kolb in 2012. Palliolinae (in part) [REDACTED] Palliolinae (in part) and Camptonectinae Chlamydinae [REDACTED] (70 mya) Pecten [REDACTED] Flexopecten [REDACTED] (247 mya) Aequipecten [REDACTED] Limidae (file shells) [REDACTED] other Pteriomorphia ( oysters , mussels ) [REDACTED] Scallops are

1932-479: Is controlled by three paired ganglia located at various points throughout their anatomy, the cerebral or cerebropleural ganglia, the pedal ganglia, and the visceral or parietovisceral ganglia. All are yellowish. The visceral ganglia are by far the largest and most extensive of the three, and occur as an almost-fused mass near the center of the animal – proportionally, these are the largest and most intricate sets of ganglia of any modern bivalve. From this, radiate all of

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2024-631: Is found in modern scallops only; both putative ancestors of modern scallops, the entoliids and the Aviculopectinidae, did not possess it. Like the true oysters (family Ostreidae ), scallops have a single central adductor muscle, thus, the inside of their shells has a characteristic central scar, marking the point of attachment for this muscle. The adductor muscle of scallops is larger and more developed than those of oysters , because scallops are active swimmers; some species of scallops are known to move en masse from one area to another. In scallops,

2116-435: Is now Blessed, and is expected to be confirmed as a Saint in the near future. This article about a location in the autonomous community of Extremadura, Spain is a stub . You can help Misplaced Pages by expanding it . Shell of Saint James See text Pectenidae Scallop ( / ˈ s k ɒ l ə p , ˈ s k æ l ə p / ) is a common name that encompasses various species of marine bivalve mollusks in

2208-485: Is one of the largest marine bivalve families and contains over 300 extant species in 60 genera. Its origin dates back to the Middle Triassic Period, approximately 240 million years ago; in terms of diversity, it has been a thriving family to the present day. Evolution from its origin has resulted in a successful and diverse group: pectinids are present in the world's seas, found in environments ranging from

2300-408: Is open to some debate). Other scallops can extend their foot from between their valves, and by contracting the muscles in their foot, they can burrow into sand. Most species of the scallop family are free-living, active swimmers, propelling themselves through the water through the adductor muscles to open and close their shells. Swimming occurs through the clapping of valves for water intake. Closing

2392-411: Is sometimes equivocal, and information about phylogeny and relationships of the species are minimal, not the least because most work has been based only on adult morphology . This family's earliest and most comprehensive taxonomic treatments were based on macroscopic morphological characters of the adult shells and represent broadly divergent classification schemes. Some level of taxonomic stability

2484-439: Is used to describe an unemployed returnee. It has negative overtones, implying the person is drifting aimlessly, and is also a homophonic expression (Chinese: 海待 ; pinyin: hǎidài , literally "sea waiting"). This expression is contrasted with the employed returnee, having a dynamic ability to travel across the ocean: the "sea turtle" (simplified Chinese: 海龟 ; traditional Chinese: 海龜 ; pinyin: hǎi gūi ) and

2576-616: The Camino de Santiago , and their style of shells are distinctive. The church itself dates to the turn of the twentieth century, but has classical architecture, appearing to be a castle. Like an older castle, this building was mostly constructed by hand. This church has a proud place in history as a place of succor for the poor and starving during the Spanish depression, World War I, and under Franco's regime. The priest who served in Alcuéscar in that era

2668-488: The D'Entrecasteaux Channel in the south of Tasmania dredging was banned in 1969, and since then divers have caught them in this area. Attempts to use lighted pots to attract lobster and crab led to the discovery that they were effective in attracting scallops. Kelp Agaraceae Akkesiphycaceae Alariaceae Aureophycaceae Chordaceae Laminariaceae Lessoniaceae Pseudochordaceae Kelps are large brown algae or seaweeds that make up

2760-585: The Laminariales that may be considered as kelp: Non-Laminariales species that may be considered as kelp: Kelp may develop dense forests with high production, biodiversity and ecological function. Along the Norwegian coast these forests cover 5,800 km , and they support large numbers of animals. Numerous sessile animals (sponges, bryozoans and ascidians) are found on kelp stipes and mobile invertebrate fauna are found in high densities on epiphytic algae on

2852-619: The Russian Far East , and former Soviet Union countries several types of kelp are of commercial importance: Saccharina latissima , Laminaria digitata , Saccharina japonica . Known locally as "Sea Cabbage" (Морская капуста in Russian), it comes in retail trade in dried or frozen, as well as in canned form and used as filler in different types of salads, soups and pastries. Because of its high concentration of iodine, brown kelp ( Laminaria ) has been used to treat goiter , an enlargement of

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2944-414: The adductor muscle , that is sold as seafood . The brightly coloured, symmetric, fan-shaped shells of scallops with their radiating and often fluted ornamentation are valued by shell collectors, and have been used since ancient times as motifs in art, architecture, and design. Owing to their widespread distribution, scallop shells are a common sight on beaches and are often brightly coloured, making them

3036-412: The heterokonts and dinoflagellates . Some scallops, including Chlamys hastata , frequently carry epibionts such as sponges and barnacles on their shells. The relationship of the sponge to the scallop is characterized as a form of mutualism, because the sponge provides protection by interfering with adhesion of predatory sea-star tube feet, camouflages Chlamys hastata from predators, or forms

3128-591: The order Laminariales . There are about 30 different genera . Despite its appearance, kelp is not a plant but a stramenopile (a group containing many protists ). Kelp grows in "underwater forests " ( kelp forests ) in shallow oceans. Kelps were previously thought to have appeared in the Miocene , 5 to 23 million years ago based on fossils from California. New fossils of kelp holdfasts from early Oligocene rocks in Washington State show that kelps were present in

3220-403: The subantarctic region. Dispersal by rafts from buoyant species also explains some evolutionary history for non-buoyant species of kelp. Since these rafts commonly have hitchhikers of other diverse species, they provide a mechanism for dispersal for species that lack buoyancy. This mechanism has been recently confirmed to be the cause of some dispersal and evolutionary history for kelp species in

3312-537: The taxonomic family Pectinidae , the scallops. However, the common name "scallop" is also sometimes applied to species in other closely related families within the superfamily Pectinoidea , which also includes the thorny oysters . Scallops are a cosmopolitan family of bivalves found in all of the world's oceans, although never in fresh water. They are one of the very few groups of bivalves to be primarily "free-living", with many species capable of rapidly swimming short distances and even migrating some distance across

3404-639: The Pectinidae have only utilized mitochondrial data. Phylogenies based only on mitochondrial sequence data do not always provide an accurate estimation on the species tree. Complicated factors can arise due to the presence of genetic polymorphisms in ancestral species and resultant lineage sorting. In molecular phylogenies of the Bivalvia, both the Spondylidae and the Propeamussiidae have been resolved as sister to

3496-510: The Pectinidae. The following are recognised in the family Pectinidae: The largest wild scallop fishery is for the Atlantic sea scallop ( Placopecten magellanicus ) found off the northeastern United States and eastern Canada. Scallops are harvested using scallop dredges or bottom trawls. Most of the rest of the world's production of scallops is from Japan (wild, enhanced, and aquaculture) and China (mostly cultured Atlantic bay scallops). In

3588-565: The abundance of species within the Pectinidae has varied greatly over time; Pectinidae was the most diverse bivalve family in the Mesozoic era , but the group almost disappeared completely by the end of the Cretaceous period . The survivors speciated rapidly during the Tertiary period . Nearly 7,000 species and subspecies names have been introduced for both fossil and recent Pectinidae. The cladogram

3680-584: The amount of glycogen stored in muscle tissue. Environmental factors, such as changes in oxidative stress parameters, can inhibit the growth and development of scallops. Seasonal changes in temperature and food availability have been shown to affect muscle metabolic capabilities. The properties of mitochondria from the phasic adductor muscle of Euvola ziczac varied significantly during their annual reproductive cycle. Summer scallops in May have lower maximal oxidative capacities and substrate oxidation than any other time in

3772-409: The anatomy of any given scallop species. The shell of a scallop consists of two sides or valves , a left valve and a right one, divided by a plane of symmetry . Most species of scallops rest on their right valve, and consequently, this valve is often deeper and more rounded than the left (i.e., upper) valve, which in many species is actually concave. With the hinge of the two valves oriented towards

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3864-455: The animal sense its position in the surrounding environment. They are connected to the pedal ganglia by short cerebral-pedal connectives. The pedal ganglia, though not fused, are situated very close to each other near the midline. From the pedal ganglia, the scallop puts out pedal nerves which control the movement of, and sensation in, its small muscular foot. Scallops have a large number (up to 200) of small (about 1 mm) eyes arranged along

3956-428: The anterior ear may be somewhat larger (the posterior ear is never larger than the anterior one, an important feature for distinguishing which valve is which). As is the case in almost all bivalves, a series of lines and/or growth rings originates at the center of the hinge, at a spot called the " beak " surrounded by a generally raised area called the " umbo ". These growth rings increase in size downwards until they reach

4048-578: The ashes of kelp). At least until the 1840s, when there were steep falls in the price of kelp, landlords wanted to create pools of cheap or virtually free labour, supplied by families subsisting in new crofting townships. Kelp collection and processing was a very profitable way of using this labour, and landlords petitioned successfully for legislation designed to stop emigration. The profitability of kelp harvesting meant that landlords began to subdivide their land for small tenant kelpers, who could now afford higher rent than their gentleman farmer counterparts. But

4140-633: The byssus as they grow larger. A very few species go on to cement themselves to a hard substrate (e.g. Chlamys distorta and Hinnites multirigosus ). However, the majority of scallops are free-living and can swim with brief bursts of speed to escape predators (mostly starfish ) by rapidly opening and closing their valves. Indeed, everything about their characteristic shell shape – its symmetry, narrowness, smooth and/ or grooved surface, small flexible hinge, powerful adductor muscle, and continuous and uniformly curved edge – facilitates such activity. They often do this in spurts of several seconds before closing

4232-485: The combined sensitivity of both retinas to light entering the eye and light retro-reflected from the mirror grants scallops exceptional contrast definition, as well as the ability to detect changing patterns of light and motion. Scallops primarily rely on their eyes as an 'early-warning' threat detection system, scanning around them for movement and shadows which could potentially indicate predators. Additionally, some scallops alter their swimming or feeding behaviour based on

4324-570: The concentric rings of their shells. Many scallops are hermaphrodites (having female and male organs simultaneously), altering their sex throughout their lives, while others exist as dioecious species, having a definite sex. In this case, males are distinguished by roe-containing white testes and females with roe-containing orange ovaries. At the age of two, they usually become sexually active, but do not contribute significantly to egg production until four. The reproduction process occurs externally through spawning, in which eggs and sperm are released into

4416-406: The curved ventral edge of the shell. The shells of most scallops are streamlined to facilitate ease of movement during swimming at some point in their lifecycles, while also providing protection from predators. Scallops with ridged valves have the advantage of the architectural strength provided by these ridges called "ribs", although the ribs are somewhat costly in weight and mass. A unique feature of

4508-589: The early 19th century, burning of kelp in Scotland was one of the principal industrial sources of soda ash (predominantly sodium carbonate ). Around 23 tons of seaweed was required to produce 1 ton of kelp ash. The kelp ash would consist of around 5% sodium carbonate. Once the Leblanc Process became commercially viable in Britain during the 1820s, common salt replaced kelp ash as raw material for sodium carbonate. Though

4600-488: The economic collapse of the kelp industry in northern Scotland during the 1820s led to further emigration, especially to North America . Natives of the Falkland Islands are sometimes nicknamed " Kelpers ". This designation is primarily applied by outsiders rather than the natives themselves . In Chinese slang , "kelp" ( simplified Chinese : 海带 ; traditional Chinese : 海帶 ; pinyin : hǎi dài ),

4692-444: The edge of their mantles. These eyes represent a particular innovation among molluscs, relying on a concave, parabolic mirror of guanine crystals to focus and retro-reflect light instead of a lens as found in many other eye types. Additionally, their eyes possess a double-layered retina, the outer retina responding most strongly to light and the inner to abrupt darkness. While these eyes are unable to resolve shapes with high fidelity,

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4784-490: The efficiency of giant kelp ( Macrocystis pyrifera ) transport anatomy looked at 6 different laminariales species to see if they had typical vascular plant allometric relationships (if SEs had a correlation with the size of an organism). Researchers expected to find the kelp’s phloem to work similarly to a plant's xylem and therefore display similar allometric trends to minimize pressure gradient . The study found no universal allometric scaling between all tested structures of

4876-412: The family Pectinidae is monophyletic, developing from a single common ancestor. The direct ancestors of Pectinidae were scallop-like bivalves of the family Entoliidae. Entoliids had auricles and a byssal notch only at youth, but they did not have a ctenolium, a comb-like arrangement along the margins of the byssal notch in Pectinidae. The ctenolium is the defining feature of the modern family Pectinidae and

4968-420: The family Pectinidae, marine bivalve molluscs within the superfamily Pectinoidea . Other families within this same superfamily share a somewhat similar overall shell shape, and some species within some of the related families are also commonly referred to as "scallops" (for example, Propeamussiidae , the glass scallops). The family Pectinidae is the most diversified of the pectinoideans in present-day oceans. It

5060-413: The flow of water. Certain kelp form kelp rafts, which can travel great distances away from the source population and colonize other areas. The bull kelp genus Durvillaea includes six species, some that have adapted buoyancy and others that have not. Those that have adapted buoyancy have done so thanks to the evolution of a gas filled structure called the pneumatocysts which is an adaptation that allows

5152-412: The food is digested in the digestive gland, an organ sometimes misleadingly referred to as the "liver, " which envelops part of the oesophagus, intestine, and entire stomach. Waste is passed on through the intestine (the terminus of which, like that of many mollusks, enters and leaves the animal's heart) and exits via the anus. Like all bivalves, scallops lack actual brains. Instead, their nervous system

5244-780: The harvesting of foods such as abalone , limpets , and mussels associated with kelp forest habitats. In 2007, Erlandson et al. suggested that kelp forests around the Pacific Rim may have facilitated the dispersal of anatomically modern humans following a coastal route from Northeast Asia to the Americas. This "kelp highway hypothesis" suggested that highly productive kelp forests supported rich and diverse marine food webs in nearshore waters, including many types of fish, shellfish, birds, marine mammals, and seaweeds that were similar from Japan to California, Erlandson and his colleagues also argued that coastal kelp forests reduced wave energy and provided

5336-500: The intertidal zone to the hadal depths. The Pectinidae play an extremely important role in many benthic communities and exhibit a wide range of shell shapes, sizes, sculptures, and cultures. Raines and Poppe listed nearly 900 species names of scallops, but most of these are considered either questionable or invalid. Raines and Poppe mentioned over 50 genera, around 250 species, and subspecies . Although species are generally well-circumscribed, their attribution to subfamilies and genera

5428-435: The kelp stipes and on kelp holdfasts. More than 100,000 mobile invertebrates per square meter are found on kelp stipes and holdfasts in well-developed kelp forests. While larger invertebrates and in particular sea urchins ( Strongylocentrotus droebachiensis ) are important secondary consumers controlling large barren ground areas on the Norwegian coast, they are scarce inside dense kelp forests. Some animals are named after

5520-420: The kelp to float higher towards the surface to photosynthesize and also aids in dispersal by floating kelp rafts. For Macrocystis pyrifera , adaptation of pneumatocysts and raft forming have made the species dispersal method so successful that the immense spread of coast in which the species can be found has been found to actually be very recently colonized . This can be observed by the low genetic diversity in

5612-466: The kelp, either because they inhabit the same habitat as kelp or because they feed on kelp. These include: Overfishing nearshore ecosystems leads to the degradation of kelp forests. Herbivores are released from their usual population regulation, leading to over-grazing of kelp and other algae. This can quickly result in barren landscapes where only a small number of species can thrive. Other major factors which threaten kelp include marine pollution and

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5704-821: The laminariales species which implies that the transport network of brown algae is only just beginning to evolve to efficiently fit their current niches. Apart from undergoing convergent evolution with plants, species of kelp have undergone convergent evolution within their own phylogeny that has led to niche conservatism . This niche conservatism means that some species of kelp have convergently evolved to share similar niches, as opposed to all species diverging into distinct niches through adaptive radiation . A 2020 study looked at functional traits (blade mass per area, stiffness, strength, etc.) of 14 species of kelp and found that many of these traits evolved convergently across kelp phylogeny. With different species of kelp filling slightly different environmental niches, specifically along

5796-802: The measure Ma “unequivocal minimum constraint for total group Pinaceae ” vascular plants have been measured as having evolved around 419–454 Ma while the ancestors of Laminariales are much younger at 189 Ma. Although these groups are distantly related as well as different in evolutionary age, there are still comparisons that can be made between the structures of terrestrial plants and kelp but in terms of evolutionary history, most of these similarities come from convergent evolution. Some kelp species including giant kelp, have evolved transport mechanisms for organic as well as inorganic compounds , similar to mechanisms of transport in trees and other vascular plants . In kelp this transportation network uses trumpet-shaped sieve elements (SEs). A 2015 study aimed to evaluate

5888-502: The muscular foot, used to attach to a firm support, such as a rock. Some can also be found on the ocean floor, moving with an extendable foot between their valves or burrowing themselves in the sand by extending and retracting their feet. Scallops are highly sensitive to shadows, vibrations, water movement, and chemical stimuli. All possess a series of 100 blue eyes, embedded on the edge of the mantle of their upper and lower valves that can distinguish between light and darkness. They serve as

5980-409: The nerves which connect the visceral ganglia to the circumpallial nerve ring which loops around the mantle and connects to all of the scallop's tentacles and eyes. This nerve ring is so well developed that, in some species, it may be legitimately considered an additional ganglion. The visceral ganglia are also the origin of the branchial nerves which control the scallop's gills. The cerebral ganglia are

6072-407: The next-largest set of ganglia and lie distinct from each other a significant distance dorsal to the visceral ganglia. They are attached to the visceral ganglia by long cerebral-visceral connectives, and to each other via a cerebral commissure that extends in an arch dorsally around the esophagus. The cerebral ganglia control the scallop's mouth via the palp nerves and connect to statocysts which help

6164-403: The northeastern Pacific Ocean by at least 32 million years ago. The organisms require nutrient-rich water with temperatures between 6 and 14 °C (43 and 57 °F). They are known for their high growth rate—the genera Macrocystis and Nereocystis can grow as fast as half a metre a day, ultimately reaching 30 to 80 metres (100 to 260 ft). Through the 19th century, the word "kelp"

6256-533: The ocean floor, where they attach themselves to objects through byssus threads. Byssus is eventually lost with adulthood, transitioning almost all scallop species into free swimmers. Rapid growth occurs within the first several years, with an increase of 50–80 % in shell height and quadrupled size in meat weight, and reaches a commercial size at about four to five years of age. The lifespans of some scallops have been known to extend over 20 years. Scallops are known to be infected by viruses , bacteria , microalgae of

6348-480: The ocean floor. A small minority of scallop species live cemented to rocky substrates as adults, while others attach themselves to stationary or rooted objects such as seagrass at some point in their lives by means of a filament they secrete called a byssal thread . The majority of species, however, live recumbent on sandy substrates, and when they sense the presence of a predator such as a starfish , they may attempt to escape by swimming swiftly but erratically through

6440-454: The price of kelp ash went into steep decline, seaweed remained the only commercial source of iodine. To supply the new industry in iodine synthesis, kelp ash production continued in some parts of West and North Scotland, North West Ireland and Guernsey. The species Saccharina latissima yielded the greatest amount of iodine (between 10 and 15 lbs per ton) and was most abundant in Guernsey. Iodine

6532-493: The quality of water, climate changes and certain invasive species. Kelp forests are some of the most productive ecosystems in the world - they are home to a great diversity of species. Many groups, like those at the Seattle Aquarium , are studying the health, habitat, and population trends in order to understand why certain kelp (like bull kelp ) thrives in some areas and not others. Remotely Operated Vehicles are used in

6624-560: The roughness of the wave disturbance regime, but can look fairly different from other members of its own species that are found in different wave disturbance regimes. Plasticity in kelps most often involves blade morphology such as the width, ruffle, and thickness of blades. Just one example is the giant bull kelp Nereocystis luetkeana , which have evolved to change blade shape in order to increase drag in water and interception of light when exposed to certain environments. Bull kelp are not unique in this adaptation; many kelp species have evolved

6716-474: The scallop family is the presence, at some point during the animal's lifecycle, of a distinctive and taxonomically important shell feature, a comb-like structure called a ctenolium located on the anterior edge of the right valve next to the valve's byssal notch. Though many scallops lose this feature as they become free-swimming adults, all scallops have a ctenolium at some point during their lives, and no other bivalve has an analogous shell feature. The ctenolium

6808-409: The sea floor between each contraction of its valves, whereas a swimming scallop stays in the water column for most or all of its contractions and travels a much greater distance (though seldom at a height of more than 1 m off the sea bed and seldom for a distance of greater than 5 m). Both jumping and swimming movements are very energy-intensive, and most scallops cannot perform more than four or five in

6900-474: The shell entirely and sinking back to the bottom of their environment. Scallops are able to move through the water column either forward/ventrally (termed swimming) by sucking water in through the space between their valves, an area called the gape, and ejecting it through small holes near the hinge line called exhalant apertures, or backward/dorsally (termed jumping) by ejecting the water out the same way it came in (i.e. ventrally). A jumping scallop usually lands on

6992-412: The shell shape tends to be highly regular, and is commonly used as an archetypal form of a seashell . Scallops possess fast ( striated ) and slow ( smooth ) adductor muscles , which have different structures and contractile properties. These muscles lie closely apposed to one another but are divided by a connective tissue sheet. The striated adductor muscle contracts very quickly for swimming, whereas

7084-560: The shell which is situated next to the byssal notch. The fossil history of scallops is rich in species and specimens. The earliest known records of true scallops (those with a ctenolium) can be found from the Triassic period , over 200 million years ago. The earliest species were divided into two groups, one with a nearly smooth exterior: Pleuronectis von Schlotheim, 1820, while the other had radial ribs or riblets and auricles: Praechlamys Allasinaz, 1972. Fossil records also indicate that

7176-401: The smooth catch adductor muscle lacks striations, and contracts for long periods, keeping shells closed with little expenditure of energy. Scallops are filter feeders , and eat plankton . Unlike many other bivalves, they lack siphons . Water moves over a filtering structure, where food particles become trapped in mucus. Next, the cilia on the structure move the food toward the mouth. Then,

7268-511: The stipes. A root-like structure, the holdfast , anchors the kelp to the substrate of the ocean. Gas-filled bladders ( pneumatocysts ) form at the base of blades of American species, such as Nereocystis lueteana, (Mert. & Post & Rupr.) to hold the kelp blades close to the surface. Growth occurs at the base of the meristem , where the blades and stipe meet. Growth may be limited by grazing. Sea urchins , for example, can reduce entire areas to urchin barrens . The kelp life cycle involves

7360-460: The surveying of sites and the data extracted is used to learn about which conditions are best suited for kelp restoration. Giant kelp can be harvested fairly easily because of its surface canopy and growth habit of staying in deeper water. Kelp ash is rich in iodine and alkali . In great amount, kelp ash can be used in soap and glass production. Until the Leblanc process was commercialized in

7452-429: The thyroid gland caused by a lack of iodine, since medieval times. An intake of roughly 150 micrograms of iodine per day is beneficial for preventing hypothyroidism. Overconsumption can lead to kelp-induced thyrotoxicosis . In 2010, researchers found that alginate , the soluble fibre substance in sea kelp, was better at preventing fat absorption than most over-the-counter slimming treatments in laboratory trials. As

7544-404: The top, one side corresponds to the animal's morphological anterior or front, the other is the posterior or rear, the hinge is the dorsal or back/top region, and the bottom corresponds to the ventral or (as it were) underside/belly. However, as many scallop shells are more or less bilaterally symmetrical ("equivalved"), as well as symmetrical front/back ("equilateral"), determining which way

7636-399: The turbidity or clarity of the water, by detecting the movement of particulate matter in the water column. Scallops are mostly free-living and active, unlike the vast majority of bivalves, which are mostly slow-moving and infaunal. All scallops are thought to start out with a byssus , which attaches them to some form of substrate such as eelgrass when they are very young. Most species lose

7728-508: The upper and lower arches. Kelp polysaccharides are used in skin care as gelling ingredients and because of the benefits provided by fucoidan . Kombu (昆布 in Japanese, and 海带 in Chinese, Saccharina japonica and others), several Pacific species of kelp, is a very important ingredient in Chinese, Japanese, and Korean cuisines. Kombu is used to flavor broths and stews (especially dashi ), as

7820-426: The valves propels water with a strong force near the hinge via the velum, a curtain-like fold of the mantle that directs water expulsion around the hinge. Scallops swim in the direction of the valve opening unless the velum directs an abrupt change in course direction. Other species of scallops can be found on the ocean floor attached to objects by byssal threads. Byssal threads are strong, silky fibers extending from

7912-503: The water during mating season and fertilized ova sink to the bottom. After several weeks, the immature scallops hatch and the larvae, miniature transparent versions of the adults called "spat", drift in the plankton until settling to the bottom again (an event called spatfall) to grow, usually attaching by means of byssal threads. Some scallops, such as the Atlantic bay scallop Argopecten irradians , are short-lived, while others can live 20 years or more. Age can often be inferred from annuli ,

8004-425: The water using jet propulsion created by repeatedly clapping their shells together. Scallops have a well-developed nervous system, and unlike most other bivalves all scallops have a ring of numerous simple eyes situated around the edge of their mantles . Many species of scallops are highly prized as a food source, and some are farmed as aquaculture . The word "scallop" is also applied to the meat of these bivalves,

8096-506: The water. Spawning typically occurs in late summer and early autumn; spring spawning may also take place in the Mid-Atlantic Bight . The females of scallops are highly fecund, capable of producing hundreds of millions of eggs per year. Once an egg is fertilized, it is then planktonic, a collection of microorganisms that drift abundantly in fresh or salt water. Larvae stay in the water column for four to seven weeks before dissipating to

8188-477: The year. This phenomenon is due to lower protein levels in adductor muscles. The scallop family is unusual in that some members of the family are dioecious (males and females are separate), while others are simultaneous hermaphrodites (both sexes in the same individual), and a few are protoandrous hermaphrodites (males when young then switching to female). Female scallops have red roe and male scallops have white roe. Spermatozoa and ova are released freely into

8280-476: Was achieved when Waller's studies in 1986, 1991, and 1993 concluded evolutionary relationships between pectinid taxa based on hypothesized morphological synapomorphies, which previous classification systems of Pectinidae failed to do. He created three Pectinidae subfamilies: Camptonectinidae, Chlamydinae and Pectininae. The framework of its phylogeny shows that repeated life habit states derive from evolutionary convergence and parallelism. Studies have determined

8372-400: Was closely associated with seaweeds that could be burned to obtain soda ash (primarily sodium carbonate). The seaweeds used included species from both the orders Laminariales and Fucales . The word "kelp" was also used directly to refer to these processed ashes. The thallus (or body) consists of flat or leaf-like structures known as blades that originate from elongated stem-like structures,

8464-479: Was extracted from kelp ash using a lixiviation process. As with sodium carbonate however, mineral sources eventually supplanted seaweed in iodine production. Alginate , a kelp-derived carbohydrate, is used to thicken products such as ice cream , jelly , salad dressing , and toothpaste , as well as an ingredient in exotic dog food and in manufactured goods. Alginate powder is also used frequently in general dentistry and orthodontics for making impressions of

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