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115-572: Before contact with Europeans, most Algonquian settlements lived by hunting and fishing, with many of them supplementing their diet by cultivating corn , beans and squash (the " Three Sisters" ). The Ojibwe cultivated wild rice . At the time of the first European settlements in North America , Algonquian peoples resided in present-day Canada east of the Rocky Mountains , New England , New Jersey , southeastern New York , Delaware , and down

230-406: A clan kinship structure. Villages were temporary and mobile. The people moved to locations of greatest natural food supply, often breaking into smaller units or gathering as the circumstances required. This custom resulted in a certain degree of intertribal mobility, especially in troubled times. In warm weather, they constructed portable wigwams , a type of hut usually with buckskin doors. In

345-609: A staple food in many parts of the world, with the total production of maize surpassing that of wheat and rice . Much maize is used for animal feed , whether as grain or as the whole plant, which can either be baled or made into the more palatable silage . Sugar-rich varieties called sweet corn are grown for human consumption, while field corn varieties are used for animal feed, for uses such as cornmeal or masa , corn starch , corn syrup , pressing into corn oil , alcoholic beverages like bourbon whiskey , and as chemical feedstocks including ethanol and other biofuels . Maize

460-594: A common sight on beaches and are often brightly coloured, making them 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

575-810: A conventional breeding program to provide optimized strains. The program began in the 1980s. Hybrid seeds are distributed in Africa by its Drought Tolerant Maize for Africa project. Tropical landraces remain an important and underused source of resistance alleles – both those for disease and for herbivores . Such alleles can then be introgressed into productive varieties. Rare alleles for this purpose were discovered by Dao and Sood, both in 2014. In 2018, Zerka Rashid of CIMMYT used its association mapping panel, developed for tropical drought tolerance traits. to find new genomic regions providing sorghum downy mildew resistance , and to further characterize known differentially methylated regions . Genetically modified maize

690-403: A corn head (with points and snap rolls instead of a reel) does not cut the stalk; it simply pulls the stalk down. The stalk continues downward and is crumpled into a mangled pile on the ground, where it usually is left to become organic matter for the soil . The ear of maize is too large to pass between slots in a plate as the snap rolls pull the stalk away, leaving only the ear and husk to enter

805-479: A degree that their population increased and they reached a density of 287 people per 100 square miles as opposed to 41 in the north. Scholars estimate that, by the year 1600, the indigenous population of New England had reached 70,000–100,000. The French encountered Algonquian peoples in this area through their trade and limited colonization of New France along the Mississippi and Ohio rivers. The historic peoples of

920-449: 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

1035-440: 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 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

1150-481: 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

1265-408: A large cob. Yellow maizes derive their color from carotenoids ; red maizes are colored by anthocyanins and phlobaphenes ; and orange and green varieties may contain combinations of these pigments. Maize has short-day photoperiodism , meaning that it requires nights of a certain length to flower. Flowering further requires enough warm days above 10 °C (50 °F). The control of flowering

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1380-499: A measure of protection against a wide range of pests. Because of its shallow roots, maize is susceptible to droughts, intolerant of nutrient-deficient soils, and prone to being uprooted by severe winds. Maize is diploid with 20 chromosomes . 83% of allelic variation within the genome derives from its teosinte ancestors, primarily due to the freedom of Zea species to outcross . Barbara McClintock used maize to validate her transposon theory of "jumping genes", for which she won

1495-526: 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

1610-614: A place but a condition, a savage rather than a civilized grain". International groups such as the Centre for Agriculture and Bioscience International consider maize the preferred common name. The word maize is used by the UN's Food and Agriculture Organization , and in the names of the International Maize and Wheat Improvement Center of Mexico, the Indian Institute of Maize Research,

1725-590: A plant that uses C 4 carbon fixation , maize is a considerably more water-efficient crop than plants that use C 3 carbon fixation such as alfalfa and soybeans . Maize is most sensitive to drought at the time of silk emergence, when the flowers are ready for pollination. In the United States, a good harvest was traditionally predicted if the maize was "knee-high by the Fourth of July ", although modern hybrids generally exceed this growth rate. Maize used for silage

1840-588: 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, 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

1955-401: 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

2070-616: A time. Historians hypothesize that this practice kept the population down, with some invoking Liebig's law of the minimum . The southern Algonquians of New England relied predominantly on slash and burn agriculture. They cleared fields by burning for one or two years of cultivation, after which the village moved to another location. This is the reason the English found the region relatively cleared and ready for planting. By using various kinds of native corn (maize), beans and squash, southern New England natives were able to improve their diet to such

2185-557: 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

2300-456: 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

2415-514: 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

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2530-447: Is a major pest of maize in Asia. Scallop 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 the taxonomic family Pectinidae , the scallops. However, the common name "scallop" is also sometimes applied to species in other closely related families within

2645-426: Is a problem in Asia. Some fungal diseases of maize produce potentially dangerous mycotoxins such as aflatoxin . In the United States, major diseases include tar spot , bacterial leaf streak , gray leaf spot , northern corn leaf blight, and Goss's wilt ; in 2022, the most damaging disease was tar spot, which caused losses of 116.8 million bushels . Maize sustains a billion dollars' worth of losses annually in

2760-526: 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

2875-408: Is composed of transposons , contains 32,540 genes. Much of it has been duplicated and reshuffled by helitrons , a group of transposable elements within maize's DNA. Maize breeding in prehistory resulted in large plants producing large ears. Modern breeding began with individuals who selected highly productive varieties in their fields and then sold seed to other farmers. James L. Reid was one of

2990-479: 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

3105-534: Is cultivated throughout the world; a greater weight of maize is produced each year than any other grain. In 2020, world production was 1.1 billion tonnes. It is afflicted by many pests and diseases ; two major insect pests, European corn borer and corn rootworms , have each caused annual losses of a billion dollars in the US. Modern plant breeding has greatly increased output and qualities such as nutrition, drought tolerance, and tolerance of pests and diseases. Much maize

3220-631: 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,

3335-414: Is harvested while the plant is green and the fruit immature. Sweet corn is harvested in the "milk stage", after pollination but before starch has formed, between late summer and early to mid-autumn. Field maize is left in the field until very late in the autumn to thoroughly dry the grain, and may, in fact, sometimes not be harvested until winter or even early spring. The importance of sufficient soil moisture

3450-533: Is now genetically modified . As a food, maize is used to make a wide variety of dishes including Mexican tortillas and tamales , Italian polenta , and American hominy grits . Maize protein is low in some essential amino acids , and the niacin it contains only becomes available if freed by alkali treatment . In Mesoamerica, maize is deified as a maize god and depicted in sculptures. Maize requires human intervention for it to propagate. The kernels of its naturally-propagating teosinte ancestor fall off

3565-485: 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

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3680-408: 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

3795-468: Is set genetically; the physiological mechanism involves the phytochrome system. Tropical cultivars can be problematic if grown in higher latitudes, as the longer days can make the plants grow tall instead of setting seed before winter comes. On the other hand, growing tall rapidly could be convenient for producing biofuel. Immature maize shoots accumulate a powerful antibiotic substance, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one ( DIMBOA ), which provides

3910-545: Is shown in many parts of Africa, where periodic drought regularly causes maize crop failure and consequent famine . Although it is grown mainly in wet, hot climates, it can thrive in cold, hot, dry or wet conditions, meaning that it is an extremely versatile crop. Maize was planted by the Native Americans in small hills of soil, in the polyculture system called the Three Sisters . Maize provided support for beans ;

4025-411: 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

4140-543: Is the domesticated variant of the four species of teosintes , which are its crop wild relatives . The teosinte origin theory was proposed by the Russian botanist Nikolai Ivanovich Vavilov in 1931, and the American Nobel Prize -winner George Beadle in 1932. The two plants have dissimilar appearance, maize having a single tall stalk with multiple leaves and teosinte being a short, bushy plant. The difference between

4255-405: Is the leaf most closely associated with a particular developing ear. This leaf and those above it contribute over three quarters of the carbohydrate ( starch ) that fills the grain. The grains are usually yellow or white in modern varieties; other varieties have orange, red, brown, blue , purple , or black grains. They are arranged in 8 to 32 rows around the cob; there can be up to 1200 grains on

4370-758: The Atlantic Coast to the Upper South , and around the Great Lakes in present-day Illinois , Indiana , Iowa , Michigan , Minnesota , and Wisconsin . The precise homeland of the Algonquian peoples is not known. At the time of the European arrival, the hegemonic Iroquois Confederacy , based in present-day New York and Pennsylvania , was regularly at war with their Algonquian neighbors. The Algonquian peoples include and have included historical populations in: Colonists in

4485-602: The Balsas River valley in Mexico's southwestern highlands, as the crop wild relative genetically most similar to modern maize. The middle part of the short Balsas River valley is the likely location of early domestication. Stone milling tools with maize residue have been found in an 8,700 year old layer of deposits in a cave not far from Iguala, Guerrero . Doebley and colleagues showed in 2002 that maize had been domesticated only once, about 9,000 years ago, and then spread throughout

4600-633: The Canadian Prairies . The Arapaho , Blackfoot and Cheyenne developed as indigenous to the Great Plains . Maize Maize / m eɪ z / ( Zea mays ), also known as corn in North American English , is a tall stout grass that produces cereal grain . It was domesticated by indigenous peoples in southern Mexico about 9,000 years ago from wild teosinte . Native Americans planted it alongside beans and squashes in

4715-478: The Three Sisters polyculture . The leafy stalk of the plant gives rise to male inflorescences or tassels which produce pollen , and female inflorescences called ears . The ears yield grain, known as kernels or seeds. In modern commercial varieties, these are usually yellow or white; other varieties can be of many colors. Maize relies on humans for its propagation. Since the Columbian exchange , it has become

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4830-412: 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

4945-566: The ocean ; and trout , smelt , striped bass and flounder in the estuaries and streams. Putting out to sea, they hunted whales , porpoises , walruses and seals . They gathered scallops , mussels , clams and crabs and, in southern New Jersey, harvested clams year-round. From April through October, natives hunted migratory birds and their eggs: Canada geese , brant , mourning doves and others. In July and August they gathered strawberries , raspberries , blueberries and nuts. In September, they split into small groups and moved up

5060-594: The 1983 Nobel Prize in Physiology or Medicine . Maize remains an important model organism for genetics and developmental biology . The MADS-box motif is involved in the development of maize flowers. The Maize Genetics and Genomics Database is funded by the US Department of Agriculture to support maize research. The International Maize and Wheat Improvement Center maintains a large collection of maize accessions tested and cataloged for insect resistance. In 2005,

5175-645: The Americas. Maize pollen dated to 7,300 years ago from San Andres, Tabasco has been found on the Caribbean coast. A primitive corn was being grown in southern Mexico, Central America, and northern South America 7,000 years ago. Archaeological remains of early maize ears, found at Guila Naquitz Cave in the Oaxaca Valley , are roughly 6,250 years old; the oldest ears from caves near Tehuacan , Puebla, are 5,450 years old. Around 4,500 years ago, maize began to spread to

5290-584: The Atlantic coast and the Saint Lawrence River. The Mahican were located in western New England in the upper Hudson River Valley (around present-day Albany, New York). These groups cultivated crops, hunted, and fished. The Algonquians of New England such as the Piscataway (who spoke Eastern Algonquian ), practised a seasonal economy. The basic social unit was the village: a few hundred people related by

5405-474: The B-vitamin niacin , the lack of which caused pellagra . Once alkali processing and dietary variety were understood and applied, pellagra disappeared in the developed world. The development of high- lysine maize and the promotion of a more balanced diet have contributed to its demise. Pellagra still exists in food-poor areas and refugee camps where people survive on donated maize. The name maize derives from

5520-672: The Illinois Country were the Shawnee , Illiniwek , Kickapoo , Menominee , Miami , Sauk and Meskwaki . The latter were also known as the Sac and Fox, and later known as the Meskwaki Indians, who lived throughout the present-day Midwest of the United States. During the nineteenth century, many Native Americans from east of the Mississippi River were displaced over great distances through

5635-671: The Maize Association of Australia, the National Maize Association of Nigeria, the National Maize Association of Ghana, the Maize Trust of South Africa, and the Zimbabwe Seed Maize Association. Maize is a tall annual grass with a single stem, ranging in height from 1.2 m (4 ft) to 4 m (13 ft). The long narrow leaves arise from the nodes or joints, alternately on opposite sides on

5750-596: The Massachusetts Bay area first encountered the Wampanoag , Massachusett , Nipmuc , Pennacook , Penobscot , Passamaquoddy , and Quinnipiac . The Mohegan , Pequot , Pocumtuc , Podunk , Tunxis , and Narragansett were based in southern New England. The Abenaki were located in northern New England: present-day Maine, New Hampshire, and Vermont in what became the United States and eastern Quebec in what became Canada. They traded with French colonists who settled along

5865-639: 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

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5980-459: 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

6095-574: The Spanish form maíz of the Taíno mahis . The Swedish botanist Carl Linnaeus used the common name maize as the species epithet in Zea mays . The name maize is preferred in formal, scientific, and international usage as a common name because it refers specifically to this one grain, unlike corn , which has a complex variety of meanings that vary by context and geographic region. Most countries primarily use

6210-544: The US National Science Foundation , Department of Agriculture, and the Department of Energy formed a consortium to sequence the maize genome . The resulting DNA sequence data was deposited immediately into GenBank , a public repository for genome-sequence data. Sequencing of the maize genome was completed in 2008. In 2009, the consortium published results of its sequencing effort. The genome, 85% of which

6325-529: The US from each of two major insect pests , namely the European corn borer or ECB ( Ostrinia nubilalis ) and corn rootworms ( Diabrotica spp ) western corn rootworm , northern corn rootworm , and southern corn rootworm . Another serious pest is the fall armyworm ( Spodoptera frugiperda ). The maize weevil ( Sitophilus zeamais ) is a serious pest of stored grain. The Northern armyworm, Oriental armyworm or Rice ear-cutting caterpillar ( Mythimna separata )

6440-577: The United States passage and enforcement of Indian removal legislation; they forced the people west of the Mississippi River to what they designated as Indian Territory . After the US extinguished Indian land claims, this area was admitted as the state of Oklahoma in the early 20th century. Ojibwe/Chippewa, Odawa , Potawatomi , and a variety of Cree groups lived in Upper Peninsula of Michigan , Western Ontario , Wisconsin , Minnesota , and

6555-565: 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

6670-584: 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

6785-409: 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

6900-455: 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

7015-428: 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

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7130-418: The beans provided nitrogen derived from nitrogen-fixing rhizobia bacteria which live on the roots of beans and other legumes ; and squashes provided ground cover to stop weeds and inhibit evaporation by providing shade over the soil. Sweet corn, harvested earlier than maize grown for grain, grows to maturity in a period of from 60 to 100 days according to variety. An extended sweet corn harvest, picked at

7245-598: The body of Christ. Maize spread to the rest of the world because of its ability to grow in diverse climates. It was cultivated in Spain just a few decades after Columbus's voyages and then spread to Italy, West Africa and elsewhere. By the 17th century, it was a common peasant food in Southern Europe. By the 18th century, it was the chief food of the southern French and Italian peasantry, especially as polenta in Italy. When maize

7360-633: 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

7475-572: The cob on their own, while those of domesticated maize do not. All maize arose from a single domestication in southern Mexico about 9,000 years ago. The oldest surviving maize types are those of the Mexican highlands. Maize spread from this region to the lowlands and over the Americas along two major paths. The centre of domestication was most likely the Balsas River valley of south-central Mexico. Maize reached highland Ecuador at least 8000 years ago. It reached lower Central America by 7600 years ago, and

7590-485: 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

7705-570: 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

7820-406: 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

7935-425: The earliest and most successful, developing Reid's Yellow Dent in the 1860s. These early efforts were based on mass selection (a row of plants is grown from seeds of one parent), and the choosing of plants after pollination (which means that only the female parents are known). Later breeding efforts included ear to row selection (C. G. Hopkins c. 1896), hybrids made from selected inbred lines (G. H. Shull, 1909), and

8050-444: 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,

8165-413: The entire ear is harvested, which requires a separate operation of a maize sheller to remove the kernels from the ear. Whole ears of maize were often stored in corn cribs , sufficient for some livestock feeding uses. Today corn cribs with whole ears, and corn binders, are less common because most modern farms harvest the grain from the field with a combine harvester and store it in bins . The combine with

8280-753: The expansion of the Inca Empire , maize was traded and transported as far south as 40° S in Melinquina, Lácar Department , Argentina, probably brought across the Andes from Chile. After the arrival of Europeans in 1492, Spanish settlers consumed maize, and explorers and traders carried it back to Europe . Spanish settlers much preferred wheat bread to maize. Maize flour could not be substituted for wheat for communion bread, since in Christian belief at that time only wheat could undergo transubstantiation and be transformed into

8395-412: 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

8510-420: 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

8625-412: 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

8740-532: The highly successful double cross hybrids using four inbred lines ( D. F. Jones c. 1918, 1922). University-supported breeding programs were especially important in developing and introducing modern hybrids. Since the 1940s, the best strains of maize have been first-generation hybrids made from inbred strains that have been optimized for specific traits, such as yield, nutrition, drought, pest and disease tolerance. Both conventional cross-breeding and genetic engineering have succeeded in increasing output and reducing

8855-538: The history of the word corn in North America that "[t]o say the word corn is to plunge into the tragi-farcical mistranslations of language and history". Similar to the British usage, the Spanish referred to maize as panizo , a generic term for cereal grains, as did Italians with the term polenta . The British later referred to maize as Turkey wheat, Turkey corn, or Indian corn; Fussell comments that "they meant not

8970-500: 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

9085-419: The machinery. The combine separates the husk and the cob, keeping only the kernels. Drying is vital to prevent or at least reduce damage by mould fungi, which contaminate the grain with mycotoxins . Aspergillus and Fusarium spp. are the most common mycotoxin sources, and accordingly important in agriculture. If the moisture content of the harvested grain is too high, grain dryers are used to reduce

9200-413: The milk stage, can be arranged either by planting a selection of varieties which ripen earlier and later, or by planting different areas at fortnightly intervals. Maize harvested as a grain crop can be kept in the field a relatively long time, even months, after the crop is ready to harvest; it can be harvested and stored in the husk leaves if kept dry. Before World War II , most maize in North America

9315-427: The moisture content by blowing heated air through the grain. This can require large amounts of energy in the form of combustible gases ( propane or natural gas ) and electricity to power the blowers. Maize is widely cultivated throughout the world, and a greater weight of maize is produced each year than any other grain. In 2020, total world production was 1.16 billion tonnes , led by the United States with 31.0% of

9430-502: 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

9545-501: The need for cropland, pesticides, water and fertilizer. There is conflicting evidence to support the hypothesis that maize yield potential has increased over the past few decades. This suggests that changes in yield potential are associated with leaf angle, lodging resistance, tolerance of high plant density, disease/pest tolerance, and other agronomic traits rather than increase of yield potential per individual plant. Certain varieties of maize have been bred to produce many ears; these are

9660-409: 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

9775-400: The new crop. The rise in maize cultivation 500 to 1,000 years ago in what is now the southeastern United States corresponded with a decline of freshwater mussels , which are very sensitive to environmental changes. Because it is cold-intolerant, in the temperate zones maize must be planted in the spring. Its root system is generally shallow, so the plant is dependent on soil moisture. As

9890-407: 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

10005-459: The north. In the United States, maize was first cultivated at several sites in New Mexico and Arizona about 4,100 years ago. During the first millennium AD, maize cultivation spread more widely in the areas north. In particular, the large-scale adoption of maize agriculture and consumption in eastern North America took place about A.D. 900. Native Americans cleared large forest and grassland areas for

10120-533: 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

10235-753: The presence of Starlink genetically modified corn, which had been approved only for animal consumption. The maize genus Zea is relatively closely related to sorghum , both being in the PACMAD clade of Old World grasses, and much more distantly to rice and wheat , which are in the other major group of grasses, the BOP clade . It is closely related to Tripsacum , gamagrass. various grasses e.g. fescue , ryegrass Hordeum (barley) Triticum (wheat) Oryza (rice) Pennisetum (fountaingrasses) Sorghum (sorghum) Tripsacum (gamagrass) Zea mays (maize) other Zea species ( teosintes ) Maize

10350-474: 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

10465-409: 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

10580-474: 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

10695-412: 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

10810-560: 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

10925-401: 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,

11040-487: The source of the " baby corn " used as a vegetable in Asian cuisine . A fast-flowering variety named mini-maize was developed to aid scientific research, as multiple generations can be obtained in a single year. One strain called olotón has evolved a symbiotic relationship with nitrogen-fixing microbes, which provides the plant with 29%–82% of its nitrogen. The International Maize and Wheat Improvement Center (CIMMYT) operates

11155-415: The stalk. Maize is monoecious , with separate male and female flowers on the same plant. At the top of the stem is the tassel, an inflorescence of male flowers; their anthers release pollen, which is dispersed by wind . Like other pollen, it is an allergen , but most of it falls within a few meters of the tassel and the risk is largely restricted to farm workers. The female inflorescence, some way down

11270-425: The stem from the tassel, is first seen as a silk, a bundle of soft tubular hairs , one for the carpel in each female flower, which develops into a kernel (often called a seed. Botanically, as in all grasses, it is a fruit, fused with the seed coat to form a caryopsis ) when it is pollinated. A whole female inflorescence develops into an ear or corncob , enveloped by multiple leafy layers or husks. The ear leaf

11385-444: The streams to the forest. There, they hunted beaver , caribou , moose and white-tailed deer . In December, when the snows began, the people created larger winter camps in sheltered locations, where they built or reconstructed longhouses. February and March were lean times. The tribes in southern New England and other northern latitudes had to rely on cached food. Northerners developed a practice of going hungry for several days at

11500-592: 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 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

11615-598: The term maize , and the name corn is used mainly in the United States and a handful of other English-speaking countries. In countries that primarily use the term maize , the word corn may denote any cereal crop, varying geographically with the local staple , such as wheat in England and oats in Scotland or Ireland. The usage of corn for maize started as a shortening of " Indian corn " in 18th-century North America. The historian of food Betty Fussell writes in an article on

11730-404: 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

11845-472: The total (table). China produced 22.4% of the global total. Many pests can affect maize growth and development, including invertebrates, weeds, and pathogens. Maize is susceptible to a large number of fungal, bacterial, and viral plant diseases . Those of economic importance include diseases of the leaf, smuts such as corn smut , ear rots and stalk rots. Northern corn leaf blight damages maize throughout its range, whereas banded leaf and sheath blight

11960-399: 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

12075-500: The two is largely controlled by differences in just two genes, called grassy tillers-1 ( gt1 , A0A317YEZ1 ) and teosinte branched-1 ( tb1 , Q93WI2 ). In the late 1930s, Paul Mangelsdorf suggested that domesticated maize was the result of a hybridization event between an unknown wild maize and a species of Tripsacum , a related genus; this has been refuted by modern genetic testing . In 2004, John Doebley identified Balsas teosinte, Zea mays subsp. parviglumis , native to

12190-582: The valleys of the Colombian Andes between 7000 and 6000 years ago. The earliest maize plants grew a single, small ear per plant. The Olmec and Maya cultivated maize in numerous varieties throughout Mesoamerica ; they cooked, ground and processed it through nixtamalization . By 3000 years ago, maize was central to Olmec culture, including their calendar, language, and myths. The Mapuche people of south-central Chile cultivated maize along with quinoa and potatoes in pre-Hispanic times. Before

12305-426: 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

12420-503: 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 ,

12535-506: 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

12650-504: The winter, they erected the more substantial longhouses , in which more than one clan could reside. They cached food supplies in more permanent, semi-subterranean structures . In the spring, when the fish were spawning, they left the winter camps to build villages at coastal locations and waterfalls. In March, they caught smelt in nets and weirs , moving about in birch bark canoes . In April, they netted alewife , sturgeon and salmon . In May, they caught cod with hook and line in

12765-477: 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

12880-476: 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

12995-458: Was harvested by hand. This involved a large number of workers and associated social events (husking or shucking bees ). From the 1890s onward, some machinery became available to partially mechanize the processes, such as one- and two-row mechanical pickers (picking the ear, leaving the stover ) and corn binders, which are reaper-binders designed specifically for maize. The latter produce sheaves that can be shocked . By hand or mechanical picker,

13110-425: Was introduced into Western farming systems, it was welcomed for its productivity. However, a widespread problem of malnutrition soon arose wherever it had become a staple food . Indigenous Americans had learned to soak maize in alkali -water — made with ashes and lime — since at least 1200–1500 BC, creating the process of nixtamalization. They did this to liberate the corn hulls, but coincidentally it also liberated

13225-466: Was one of the 26 genetically engineered food crops grown commercially in 2016. The vast majority of this is Bt maize . Genetically modified maize has been grown since 1997 in the United States and Canada; by 2016, 92% of the US maize crop was genetically modified. As of 2011, herbicide-tolerant maize and insect-resistant maize varieties were each grown in over 20 countries. In September 2000, up to $ 50 million worth of food products were recalled due to

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