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Polycephaly
Polycephaly is the condition of having more than one head. The term is derived from the Greek stems ''poly'' (Greek: "πολύ") meaning "many" and ''kephalē'' (Greek: "κεφαλή") meaning "head". A polycephalic organism may be thought of as one being with a supernumerary body part, or as two or more beings with a shared body. Two-headed animals (called bicephalic or dicephalic) and three-headed (tricephalic) animals are the only type of multi-headed creatures seen in the real world, and form by the same process as conjoined twins from monozygotic twin embryos. In humans, there are two forms of twinning that can lead to two heads being supported by a single torso. In dicephalus parapagus dipus, the two heads are side by side. In craniopagus parasiticus, the two heads are joined directly to each other, but only one head has a functional torso. Survival to adulthood is rare, but does occur in some forms of dicephalus parapagus dipus. There are many occurrences of mult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supernumerary Body Part
Supernumerary body parts are most commonly a congenital disorder involving the growth of an additional part of the body and a deviation from the body plan. Body parts may be easily visible or hidden away, such as internal organs. Many additional body parts form by the same process as conjoined twins: the zygote begins to split but fails to completely separate. This condition may also be a symptom of repeated occurrences of continuous inbreeding in a genetic line. Specific types of occurrence Specific types of additional body parts include: * Accessory breast – one or more additional breastsOnline Mendelian Inheritance in Man. Nipples, Supernumerary. Accessed 10 July 2006. *Accessory spleen – one or more additional spleens *Cervical rib – an additional rib *Diphallia – having two penes/penises * Hyperdontia – additional teeth *Pelvic digit – a bony growth in the soft tissue of the pelvic region *Polycephaly – an extra head *Polydactyly – additional fingers or to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conjoined Twins
Conjoined twins, popularly referred to as Siamese twins, are twins joined '' in utero''. It is a very rare phenomenon, estimated to occur in anywhere between one in 50,000 births to one in 200,000 births, with a somewhat higher incidence in southwest Asia and Africa. Approximately half are stillborn, and an additional one-third die within 24 hours. Most live births are female, with a ratio of 3:1. Two possible explanations of the cause of conjoined twins have been proposed. The one that is generally accepted is ''fission'', in which the fertilized egg splits partially. The other explanation, no longer believed to be accurate, is ''fusion'', in which the fertilized egg completely separates, but stem cells (that search for similar cells) find similar stem cells on the other twin and fuse the twins together. Conjoined twins and some monozygotic, but not conjoined, twins share a single common chorion, placenta, and amniotic sac '' in utero''. Chang and Eng Bunker (1811–1874) we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-headed Girl
Polycephaly is the condition of having more than one head. The term is derived from the Greek stems ''poly'' (Greek: "πολύ") meaning "many" and ''kephalē'' (Greek: "κεφαλή") meaning "head". A polycephalic organism may be thought of as one being with a supernumerary body part, or as two or more beings with a shared body. Two-headed animals (called bicephalic or dicephalic) and three-headed (tricephalic) animals are the only type of multi-headed creatures seen in the real world, and form by the same process as conjoined twins from monozygotic twin embryos. In humans, there are two forms of twinning that can lead to two heads being supported by a single torso. In dicephalus parapagus dipus, the two heads are side by side. In craniopagus parasiticus, the two heads are joined directly to each other, but only one head has a functional torso. Survival to adulthood is rare, but does occur in some forms of dicephalus parapagus dipus. There are many occurrences of multi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicephalus Parapagus Dipus
Skeletal structure of dicephalic twins. B. C. Hirst & G. A. Piersol, ''Human monstrosities''. Wellcome L0027955. (1893) Dicephalic parapagus () is a rare form of partial twinning with two heads side by side on one torso. Infants conjoined this way are sometimes called "two-headed babies" in popular media. The condition is also called parapagus dicephalus. If carried to term, most dicephalic twins are stillborn, or die soon after birth. A small number are known to have survived to adulthood. The extent to which limbs and organs are duplicated varies from case to case. One head may be only partially developed (anencephalic), or both may be complete. In some cases, two complete hearts are present as well, which improves their chances of survival. The total number of arms may be two, three or four. Their prospects are best if no attempt is made to separate them, except in cases in which one twin is clearly dying. Terminology Dicephalus means two-headed. Parapagus means joined si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Partridge
A partridge is a medium-sized Galliformes, galliform bird in any of several genera, with a wide Indigenous (ecology), native distribution throughout parts of Europe, Asia and Africa. Several species have been introduced to the Americas. They are sometimes grouped in the Perdicinae subfamily of the Phasianidae (pheasants, quail, etc.). However, molecular research suggests that partridges are not a distinct taxon within the family Phasianidae, but that some species are closer to the pheasants, while others are closer to the junglefowl. Description Partridges are medium-sized Game (hunting), game birds, generally intermediate in size between the larger pheasants, smaller quail; they're ground-dwelling birds that feature variable plumage colouration across species, with most tending to grey and brown. Range and habitat Partridges are native to Europe, Asia, Africa, and the Middle East. Some species are found nesting on steppes or agricultural land, while other species prefer mor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turtle
Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked turtles), which differ in the way the head retracts. There are 360 living and recently extinct species of turtles, including land-dwelling tortoises and freshwater terrapins. They are found on most continents, some islands and, in the case of sea turtles, much of the ocean. Like other Amniote, amniotes (reptiles, birds, and mammals) they breathe air and do not lay eggs underwater, although many species live in or around water. Turtle shells are made mostly of bone; the upper part is the domed Turtle shell#Carapace, carapace, while the underside is the flatter plastron or belly-plate. Its outer surface is covered in scale (anatomy), scales made of keratin, the material of hair, horns, and claws. The carapace bones deve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snake
Snakes are elongated limbless reptiles of the suborder Serpentes (). Cladistically squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales much like other members of the group. Many species of snakes have skulls with several more joints than their lizard ancestors and relatives, enabling them to swallow prey much larger than their heads ( cranial kinesis). To accommodate their narrow bodies, snakes' paired organs (such as kidneys) appear one in front of the other instead of side by side, and most only have one functional lung. Some species retain a pelvic girdle with a pair of vestigial claws on either side of the cloaca. Lizards have independently evolved elongate bodies without limbs or with greatly reduced limbs at least twenty-five times via convergent evolution, leading to many lineages of legless lizards. These resemble snakes, but several common groups of legless lizards have eyelids and external ears, which snakes lack, althoug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish
A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can be grouped into the more basal (phylogenetics), basal jawless fish and the more common jawed fish, the latter including all extant taxon, living cartilaginous fish, cartilaginous and bony fish, as well as the extinct placoderms and acanthodians. In a break to the long tradition of grouping all fish into a single Class (biology), class (Pisces), modern phylogenetics views fish as a paraphyletic group. Most fish are ectotherm, cold-blooded, their body temperature varying with the surrounding water, though some large nekton, active swimmers like white shark and tuna can hold a higher core temperature. Many fish can communication in aquatic animals#Acoustic, communicate acoustically with each other, such as during courtship displays. The stud ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boston
Boston is the capital and most populous city in the Commonwealth (U.S. state), Commonwealth of Massachusetts in the United States. The city serves as the cultural and Financial centre, financial center of New England, a region of the Northeastern United States. It has an area of and a population of 675,647 as of the 2020 United States census, 2020 census, making it the third-largest city in the Northeastern United States after New York City and Philadelphia. The larger Greater Boston metropolitan statistical area has a population of 4.9 million as of 2023, making it the largest metropolitan area in New England and the Metropolitan statistical area, eleventh-largest in the United States. Boston was founded on Shawmut Peninsula in 1630 by English Puritans, Puritan settlers, who named the city after the market town of Boston, Lincolnshire in England. During the American Revolution and American Revolutionary War, Revolutionary War, Boston was home to several seminal events, incl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Massachusetts
Massachusetts ( ; ), officially the Commonwealth of Massachusetts, is a U.S. state, state in the New England region of the Northeastern United States. It borders the Atlantic Ocean and the Gulf of Maine to its east, Connecticut and Rhode Island to its south, New Hampshire and Vermont to its north, and New York (state), New York to its west. Massachusetts is the List of U.S. states and territories by area, sixth-smallest state by land area. With a 2024 U.S. Census Bureau-estimated population of 7,136,171, its highest estimated count ever, Massachusetts is the most populous state in New England, the List of U.S. states and territories by population, 16th-most-populous in the United States, and the List of states and territories of the United States by population density, third-most densely populated U.S. state, after New Jersey and Rhode Island. Massachusetts was a site of early British colonization of the Americas, English colonization. The Plymouth Colony was founded in 16 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
