A mannequin (sometimes spelled as manikin and also called a dummy , lay figure , or dress form ) is a doll , often articulated, used by artists , tailors , dressmakers , window dressers and others, especially to display or fit clothing and show off different fabrics and textiles. Previously, the English term referred to human models and muses (a meaning which it still retains in French and other European languages); the meaning as a dummy dating from the start of World War II .
105-425: Life-sized mannequins with simulated airways are used in the teaching of first aid , CPR , and advanced airway management skills such as tracheal intubation . During the 1950s, mannequins were used in nuclear tests to help show the effects of nuclear weapons on humans. Also referred to as mannequins are the human figures used in computer simulation to model the behavior of the human body. Mannequin comes from
210-454: A census , the systematic recording of an entire population of a region. The data may be used for calculating metrics of demography such as sex, gender, age, education, employment, etc.; this information is utilized for civic, political, economic, industrial, and environmental assessment and planning. Commercial motivation for understanding variation in human populations arises from the competitive advantage of tailoring products and services for
315-463: A heterozygote or carrier of the sickle-cell disease gene confers some protection against malaria, apparently enough to maintain the gene in populations of malarial areas. In a homozygous dose it is a significant disability. Each trait has its own advantages and disadvantages, but sometimes a trait that is found desirable may not be favorable in terms of certain biological factors such as reproductive fitness, and traits that are not highly valued by
420-612: A DNA fingerprint is constructed by extracting a DNA sample from body tissue or fluid. Then, it is segmented using restriction enzymes and each segment marked with probes then exposed on X-ray film. The segments form patterns of black bars;the DNA fingerprint. DNA Fingerprints are used in conjunction with other methods in order to individuals information in Federal programs such as CODIS (Combined DNA Index System for Missing Persons) in order to help identify individuals Mitochondrial DNA , which
525-447: A climate where there is a lot of exposure to sunlight have a darker color of skin tone. Evolution has caused production of folate ( folic acid ) from UV radiation, thus giving them darker skin tone with more melanin to make sure child development is smooth and successful. Conversely, people who live farther away from the equator have a lighter skin tone. This is due to a need for an increased exposure and absorbance of sunlight to make sure
630-592: A complex combination of genetics and environment. Many genetic differences ( polymorphisms ) have little effect on health or reproductive success but help to distinguish one population from another. It is helpful for researchers in the field of population genetics to study ancient migrations and relationships between population groups. Other important factors of environmental factors include climate and disease. Climate has effects on determining what kinds of human variation are more adaptable to survive without much restrictions and hardships. For example, people who live in
735-421: A decision that should be taken when the child is old enough to decide for himself. Similarly, sex reassignment surgery offers psychiatric health benefits to transgender people but is seen as unethical by some Christians, especially when performed on children. Much controversy surrounds the assigning or distinguishing of some variations, especially since differences between groups in a society or between societies
840-540: A desirable phenotype by the majority of people, and the phenotype of very tall women has not been highly favored in the past. Nevertheless, values placed on traits can change over time. Such an example is homosexuality. In Ancient Greece, what in present terms would be called homosexuality, primarily between a man and a young boy, was not uncommon and was not outlawed. However, homosexuality became more condemned. Attitudes towards homosexuality alleviated in modern times. Acknowledgement and study of human differences does have
945-425: A given sex, vary in close to a "normal" or Gaussian distribution . Other characteristics (e.g., skin color ) vary continuously in a population, but the continuum may be socially divided into a small number of distinct categories. Then, there are some characteristics that vary bimodally (for example, handedness ), with fewer people in intermediate categories. When an inherited difference of body structure or function
1050-579: A healthy phenotype largely rests on nutritional decision-making skills. The concept that nutrition and diet affect phenotype extends to what the mother eats during pregnancy, which can have drastic effects on the outcome of the phenotype of the child. A recent study by researchers at the MRC International Nutrition Group shows that "methylation machinery can be disrupted by nutrient deficiencies and that this can lead to disease" susceptibility in newborn babies. The reason for this
1155-464: A human difference of less negative value. The extreme exercise of social valuation of human difference is in the definition of "human." Differences between humans can lead to an individual's "nonhuman" status, in the sense of withholding identification, charity, and social participation. Views of these variations can change enormously between cultures over time. For example, nineteenth-century European and American ideas of race and eugenics culminated in
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#17328011762481260-574: A hypothetical "average" that does not help them identify or understand the significant amount of normal variation seen in the real world. Mannequins were a frequent motif in the works of many early 20th-century artists, notably the metaphysical painters Giorgio de Chirico , Alberto Savinio and Carlo Carrà . Shop windows displaying mannequins were a frequent photographic subject for Eugène Atget . Mannequins have been used in horror and science fiction. The Twilight Zone episode " The After Hours " (1960) involves mannequins taking turns living in
1365-411: A left and a right main bronchus . The bronchi branch off into smaller sections inside the lungs, called bronchioles . These bronchioles give rise to the air sacs in the lungs called the alveoli . The lungs are the largest organs in the lower respiratory tract. The lungs are suspended within the pleural cavity of the thorax. The pleurae are two thin membranes, one cell layer thick, which surround
1470-437: A low resistance pathway for airflow. It provides a major defense role in its filtering abilities. The respiratory zone includes the respiratory bronchioles, alveolar ducts, and alveoli, and is the site of oxygen and carbon dioxide exchange with the blood. The respiratory bronchioles and the alveolar ducts are responsible for 10% of the gas exchange. The alveoli are responsible for the other 90%. The respiratory zone represents
1575-514: A mannequin factory and falls in love with one of the mannequins, imagining it as his childhood crush. Military use of mannequins is recorded amongst the ancient Chinese, such as at the siege of Yongqiu . The besieged Tang army lowered scarecrows down the walls of their castles to lure the fire of the enemy arrows. In this way, they renewed their supplies of arrows. Dummies were also used in the trenches in World War I to lure enemy snipers away from
1680-402: A process called mucociliary clearance , they prevent mucus accumulation in the lungs. Macrophages in the alveoli are part of the immune system which engulf and digest any inhaled harmful agents. Hair in the nostrils plays a protective role, trapping particulate matter such as dust. These hairs, called vibrissae, are thicker than body hair and effectively block larger particles from entering
1785-503: A recessive characteristic resulting from a past mutation. However, it is now understood that eye color is controlled by various genes, and thus, may not follow as distinct a pattern as previously believed. The trait is still the result of variance in genetic sequence between individuals as a result of inheritance from their parents. Common traits which may be linked to genetic patterns are earlobe attachment, hair color, and hair growth patterns. In terms of evolution , genetic mutations are
1890-511: A single loci or multiple loci, labeling said biological traits as either monogenic or polygenic , respectively. Concerning polygenic traits it may be essential to be mindful of inter-genetic interactions or epistasis . Although epistasis is a significant genetic source of biological variation, it is only additive interactions that are heritable as other epistatic interactions involve recondite inter-genetic relationships. Epistatic interactions in of themselves vary further with their dependency on
1995-550: A social value dimension. Examples of variations which may be given different values in different societies include skin color and/or body structure. Race and sex have a strong value difference, while handedness has a much weaker value difference. The values given to different traits among human variability are often influenced by what phenotypes are more prevalent locally. Local valuation may affect social standing, reproductive opportunities, or even survival. Differences may vary or be distributed in various ways. Some, like height for
2100-460: A source of variation that identifies protein variants of the same gene due to amino acid substitutions in proteins. After grinding tissue to release the cytoplasm, wicks are used to absorb the resulting extract and placed in a slit cut into a starch gel. A low current is run across the gel resulting in a positive and negative ends. Proteins are then separated by charge and size, with the smaller and more highly charged molecules moving more quickly across
2205-512: A specific target market. A business may undertake some form of market research in order to collect data on customer preference and behavior and implement changes which align with the results. Both individuals and entire societies and cultures place values on different aspects of human variability; however, values can change as societies and cultures change. Not all people agree on the values or relative rankings, and neither do all societies and cultures. Nonetheless, nearly all human differences have
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#17328011762482310-536: A teaching aid for pregnancy and childbirth. Each figure could be opened up to reveal internal organs and sometimes fetuses. There are only 180 known surviving ancient medical manikins worldwide. Today, medical simulation mannequins, models or related artefacts such as SimMan, the Transparent Anatomical Manikin or Harvey are widely used in medical education . The term manikin refers exclusively to these types of models, though mannequin
2415-420: A wide range of uses, such as tailoring the size and shape of manufactured items. See Ergonomics . Possession of above average amounts of some abilities is valued by most societies. Some of the traits that societies try to measure by perception are intellectual aptitude in the form of ability to learn, artistic prowess, strength, endurance, agility, and resilience. Each individual's distinctive differences, even
2520-462: Is 480 million. When the diaphragm contracts, a negative pressure is generated in the thorax and air rushes in to fill the cavity. When that happens, these sacs fill with air, making the lung expand. The alveoli are rich with capillaries, called alveolar capillaries. Here the red blood cells absorb oxygen from the air and then carry it back in the form of oxyhaemaglobin, to nourish the cells. The red blood cells also carry carbon dioxide (CO 2 ) away from
2625-436: Is a common lower respiratory disease that can be caused by exposure to harmful chemicals, or prolonged use of tobacco. This disease is chronic and progressive, the damage to the lungs is irreversible and eventually fatal. COPD destroys the alveoli, and lung tissue which makes breathing very difficult, causing shortness of breath , hyperventilation , and raised chest. The decreased number of alveoli causes loss of oxygen supply to
2730-484: Is a fetus or child with a significant disability. On one end are people who would argue that Down syndrome is not a disability but a mere "difference," and on the other those who consider it such a calamity as to assume that such a child is better off " not born ". For example, in India and China, being female is widely considered such a negatively valued human difference that female infanticide occurs such to severely affect
2835-495: Is a known endocrine disruptor that mimics the hormone estradiol and can be found in various plastic products. BPA seeps into food or drinks when the plastic containing it is heated up and begins to melt. When these contaminated substances are consumed, especially often and over long periods of time, one's risk of diabetes and cardiovascular disease increases. BPA also has the potential to alter "physiological weight control patterns." Examples such as this demonstrate that preserving
2940-530: Is also called the voice box and has the associated cartilage that produces sound. The tract consists of the nasal cavity and paranasal sinuses , the pharynx ( nasopharynx , oropharynx and laryngopharynx ) and sometimes includes the larynx. The lower respiratory tract or lower airway is derived from the developing foregut and consists of the trachea , bronchi (primary, secondary and tertiary), bronchioles (including terminal and respiratory), and lungs (including alveoli ). It also sometimes includes
3045-459: Is also used when designing safety equipment such as seat belts. In biometrics , measurements of fingerprints and iris patterns can be used for secure identification purposes. Human genomics and population genetics are the study of the human genome and variome , respectively. Studies in these areas may concern the patterns and trends in human DNA . The Human Genome Project and The Human Variome Project are examples of large scale studies of
3150-464: Is because methyl groups have the ability to silence certain genes. Increased deficiencies of various nutrients such as this have the potential to permanently change the epigenetics of the baby. Genetic variation in humans may mean any variance in phenotype which results from heritable allele expression, mutations , and epigenetic changes. While human phenotypes may seem diverse, individuals actually differ by only 1 in every 1,000 base pairs and
3255-454: Is breathed in through the nose to the nasal cavity , where a layer of nasal mucosa acts as a filter and traps pollutants and other harmful substances found in the air. Next, air moves into the pharynx , a passage that contains the intersection between the oesophagus and the larynx . The opening of the larynx has a special flap of cartilage, the epiglottis , that opens to allow air to pass through but closes to prevent food from moving into
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3360-532: Is deadly if not treated. Some of these cancers have environmental causes such as smoking. When a tobacco product is inhaled, the smoke paralyzes the cilia, causing mucus to enter the lungs. Frequent smoking, over time, causes the cilia hairs to die and can no longer filter mucus. Tar from the smoke inhaled enters the lungs, turning the pink-coloured lungs black. The accumulation of this tar could eventually lead to lung cancer , or chronic obstructive pulmonary disease . Chronic obstructive pulmonary disease (COPD)
3465-414: Is divided into the upper airways and lower airways . The upper airways or upper respiratory tract includes the nose and nasal passages, paranasal sinuses , the pharynx , and the portion of the larynx above the vocal folds (cords). The lower airways or lower respiratory tract includes the portion of the larynx below the vocal folds, trachea , bronchi and bronchioles . The lungs can be included in
3570-427: Is interspersed with goblet cells that secrete a protective mucus . This helps to filter waste, which is eventually either swallowed into the highly acidic stomach environment or expelled via spitting. The epithelium lining the respiratory tract is covered in small hairs called cilia . These beat rhythmically out from the lungs, moving secreted mucus foreign particles toward the laryngopharynx upwards and outwards, in
3675-474: Is not allowed to cook or enter spiritual areas because she is "impure" and "cursed". There has been large-scale renegotiation of the social significance of variations which reduce the ability of a person to do one or more functions in western culture. Laws have been passed to alleviate the reduction of social opportunity available to those with disabilities . The concept of "differently abled" has been pushed by those persuading society to see limited incapacities as
3780-456: Is often also used. In first aid courses, manikins may be used to demonstrate methods of giving first aid (e.g., resuscitation ). Fire and coastguard services use mannequins to practice life-saving procedures. The mannequins have similar weight distribution to a human. Special obese mannequins and horse mannequins have also been made for similar purposes. Over-reliance on mass-produced mannequins has been criticized for teaching medical students
3885-442: Is often debated as part of either a person's "essential" nature or a socially constructed attribution. For example, there has long been a debate among sex researchers on whether sexual orientation is due to evolution and biology (the " essentialist " position), or a result of mutually reinforcing social perceptions and behavioral choices (the " constructivist " perspective). The essentialist position emphasizes inclusive fitness as
3990-411: Is only passed from mother to child. The first human population studies based on mitochondrial DNA were performed by restriction enzyme analyses (RFLPs) and revealed differences between the four ethnic groups (Caucasian, Amerindian, African, and Asian). Differences in mtDNA patterns have also been shown in communities with a different geographic origin within the same ethnic group Alloenzymic variation,
4095-513: Is partly heritable and partly acquired ( nature vs. nurture debate). As the human species exhibits sexual dimorphism , many traits show significant variation not just between populations but also between the sexes . Human variability is attributed to a combination of environmental and genetic sources including: For the genetic variables listed above, few of the traits characterizing human variability are controlled by simple Mendelian inheritance . Most are polygenic or are determined by
4200-417: Is primarily the result of inherited genetic differences. Pure consideration of alleles is often referred to as Mendelian Genetics , or more properly Classical Genetics , and involves the assessment of whether a given trait is dominant or recessive and thus, at what rates it will be inherited. The color of one's eyes was long believed to occur with a pattern of brown-eye dominance, with blue eyes being
4305-420: Is severe enough to cause a significant hindrance in certain perceived abilities, it is termed a genetic disease , but even this categorization has fuzzy edges. There are many instances in which the degree of negative value of a human difference depends completely on the social or physical environment. For example, in a society with a large proportion of deaf people (as Martha's Vineyard in the 19th century), it
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4410-499: Is the effective population size. Single-nucleotide polymorphism or SNPs are variations of a single nucleotide . SNPs can occur in coding or non-coding regions of genes and on average occur once every 300 nucleotides . SNPs in coding regions can cause synonymous , missense , and nonsense mutations . SNPs have shown to be correlated with drug responses and risk of diseases such as sickle-cell anemia , Alzheimer's disease , cystic fibrosis, and more. DNA profiling , whereby
4515-613: The French word mannequin , which had acquired the meaning "an artist's jointed model", which in turn came from the Flemish word manneken , meaning "little man, figurine", referring to late Middle Ages practice in Flanders whereby public display of even women's clothes was performed by male pages (boys). Fashion shops in Paris ordered dolls in reed from Flemish merchants. Flanders
4620-621: The Middle Stone Age and the Acheulean – identified as a specific 'cultural phases' of humanity with a number of characteristics – lasted substantially longer in some places or 'ended' at times over 100,000 years apart, highlight a significant spatiotemporal cultural variability in and complexity of the sociocultural history and evolution of humanity. In some cases cultural factors may be intertwined with genetic and environmental factors. Measurement of human variation can fall under
4725-484: The United States , circumcision is practiced on a majority of males, as well as sex reassignment on intersex infants, with substantial emphasis on cultural and religious norms. Circumcision is highly controversial because although it offers health benefits, such as less chance of urinary tract infections, STDs, and penile cancer, it is considered a drastic procedure that is not medically mandatory and argued as
4830-413: The bronchi and bronchioles , which it completely encircles. Instead of hard cartilage, the bronchi and bronchioles are composed of elastic tissue. The lungs are made up of thirteen different kinds of cells, eleven types of epithelial cell and two types of mesenchymal cell. The epithelial cells form the lining of the tracheal, and bronchial tubes, while the mesenchymal cells line the lungs. Most of
4935-450: The mouse has up to 13 generations. Proximal divisions (those closest to the top of the tree, such as the bronchi) mainly function to transmit air to the lower airways. Later divisions including the respiratory bronchiole, alveolar ducts, and alveoli, are specialized for gas exchange . The trachea is the largest tube in the respiratory tract and consists of tracheal rings of hyaline cartilage . It branches off into two bronchial tubes,
5040-405: The pleurae – a two-layered protective barrier. The inner visceral pleura covers the surface of the lungs, and the outer parietal pleura is attached to the inner surface of the thoracic cavity. The pleurae enclose a cavity called the pleural cavity that contains pleural fluid . This fluid is used to decrease the amount of friction that lungs experience during breathing. The respiratory tract
5145-409: The respiratory center in the medulla oblongata , the motor neurons controlling the muscles also receive tonic innervation that sets a baseline level of stiffness and size. The diaphragm is the primary muscle that allows for lung expansion and contraction. Smaller muscles between the ribs, the external intercostals , assist with this process. The epithelial lining of the upper respiratory tract
5250-562: The social sciences , social research is conducted and collected data is analyzed under statistical methods. The methodologies of this research can be divided into qualitative and quantitative designs. Some example subdisciplines include: Anthropometry is the study of the measurements of different parts of the human body. Common measurements include height , weight , organ size ( brain , stomach , penis , vagina ), and other bodily metrics such as waist–hip ratio . Each measurement can vary significantly between populations; for instance,
5355-440: The thoracic cavity , are protected from physical damage by the rib cage . At the base of the lungs is a sheet of skeletal muscle called the diaphragm . The diaphragm separates the lungs from the stomach and intestines . The diaphragm is also the main muscle of respiration involved in breathing , and is controlled by the sympathetic nervous system . The lungs are encased in a serous membrane that folds in on itself to form
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#17328011762485460-469: The 15th century, when miniature " milliners' mannequins " were used to demonstrate fashions for customers. Full-scale, wickerwork mannequins came into use in the mid-18th century. Wirework mannequins were manufactured in Paris from 1835. The first female mannequins, made of papier-mâché , were made in France in the mid-19th century. Mannequins were later made of wax to produce a more lifelike appearance. In
5565-430: The 16th through the 23rd division of the respiratory tract. From the bronchi, the dividing tubes become progressively smaller with an estimated 20 to 23 divisions before ending at an alveolus. The upper respiratory tract can refer to the parts of the respiratory system lying above the vocal folds , or above the cricoid cartilage . The larynx is sometimes included in both the upper and lower airways. The larynx
5670-404: The 1920s, wax was supplanted by a more durable composite made with plaster. Modern day mannequins are made from a variety of materials, the primary ones being fiberglass and plastic . The fiberglass mannequins are usually more expensive than the plastic ones, tend to be not as durable, but are significantly more realistic. Plastic mannequins, on the other hand, are a relatively new innovation in
5775-493: The airway. From the larynx , air moves into the trachea and down to the intersection known as the carina that branches to form the right and left primary (main) bronchi . Each of these bronchi branches into a secondary (lobar) bronchus that branches into tertiary (segmental) bronchi , that branch into smaller airways called bronchioles that eventually connect with tiny specialized structures called alveoli that function in gas exchange . The lungs which are located in
5880-536: The attempts of the Nazi -led German society of the 1930s to deny not just reproduction, but life itself to a variety of people with "differences" attributed in part to biological characteristics. Hitler and Nazi leaders wanted to create a " master race " consisting of only Aryans, or blue-eyed, blonde-haired, and tall individuals, thus discriminating and attempting to exterminate those who didn't fit into this ideal. Contemporary controversy continues over "what kind of human"
5985-462: The average height of males of European descent is 178 cm ± 7 cm and of females of European descent is 165 cm ± 7 cm. Meanwhile, average height of Nilotic males in Dinka is 181.3 cm. Applications of anthropometry include ergonomics , biometrics , and forensics . Knowing the distribution of body measurements enable designers to build better tools for workers. Anthropometry
6090-629: The blocking of expression or changes to histone protein structuring as a result of environmental or biological cues. Such alterations influence how genetic material is handled by the cell and to what extent certain DNA sections are expressed and compose the epigenome . The division between what can be considered as a genetic source of biological variation and not becomes immensely arbitrary as we approach aspects of biological variation such as epigenetics. Indeed, gene specific gene expression and inheritance may be reliant on environmental influences. Archaeological findings such as those that indicate that
6195-460: The body can produce enough vitamin D for survival. Blackfoot disease is a disease caused by environmental pollution and causes people to have black, charcoal-like skin in the lower limbs. This is caused by arsenic pollution in water and food source. This is an example of how disease can affect human variation. Another disease that can affect human variation is syphilis, a sexual transmitted disease. Syphilis does not affect human variation until
6300-402: The boundaries of " wellness ", "wholeness," or " normality ." In some cultures, differences in physical appearance, mental ability, and even sex can exclude one from traditions, ceremonies, or other important events, such as religious service. For example, in India, menstruation is not only a taboo subject but also traditionally considered shameful. Depending on beliefs, a woman who is menstruating
6405-649: The bronchial tubes; as a result, the air passage will swell up, or close up completely. In general, air is inhaled through the nose . It can be inhaled through the mouth if it is not possible to breathe through the nose. However, chronic mouth breathing can cause a dry mouth and lead to infections. Normal variant Human variability , or human variation , is the range of possible values for any characteristic, physical or mental , of human beings . Frequently debated areas of variability include cognitive ability , personality , physical appearance ( body shape , skin color , etc.) and immunology . Variability
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#17328011762486510-457: The bronchioles. The same goes for goblet cells, although there are scattered ones in the first bronchioles. Cartilage is present until the small bronchi . In the trachea, they are C-shaped rings of hyaline cartilage , whereas in the bronchi the cartilage takes the form of interspersed plates. Smooth muscle starts in the trachea, where it joins the C-shaped rings of cartilage. It continues down
6615-452: The car driven by another agent and walked away, so that any counterintelligence officers monitoring the agent's car would believe that he was still in the car. Airway The respiratory tract is the subdivision of the respiratory system involved with the process of conducting air to the alveoli for the purposes of gas exchange in mammals . The respiratory tract is lined with respiratory epithelium as respiratory mucosa. Air
6720-474: The cells in the form of carbaminohemoglobin and release it into the alveoli through the alveolar capillaries. When the diaphragm relaxes, a positive pressure is generated in the thorax and air rushes out of the alveoli expelling the carbon dioxide. The respiratory tract is covered in epithelium , which varies down the tract. There are glands and mucus produced by goblet cells in parts, as well as smooth muscle , elastin or cartilage . The epithelium from
6825-406: The entire human population to collect data which can be analyzed to understand genomic and genetic variation in individuals, respectively. Genetic drift is one method by which variability occurs in populations. Unlike natural selection , genetic drift occurs when alleles decrease randomly over time and not as a result of selection bias. Over a long history, this can cause significant shifts in
6930-456: The following: Demography is a branch of statistics and sociology concerned with the statistical study of populations, especially humans. A demographic analysis can measure various metrics of a population, most commonly metrics of size and growth, diversity in culture, ethnicity, language, religious belief, political belief, etc. Biodemography is a subfield which specifically integrates biological understanding into demographics analysis. In
7035-653: The frequency of that allele reaches 1 and the frequency of the other allele reaches 0. The probability that any allele is fixed is proportional to the frequency of that allele. For two alleles with frequencies p and q, the probability that p will be fixed is p. The expected number of generations for an allele with frequency p to be fixed is: T ¯ fixed = − 4 N e ( 1 − p ) ln ( 1 − p ) p {\displaystyle {\bar {T}}_{\text{fixed}}={\frac {-4N_{e}(1-p)\ln(1-p)}{p}}} Where N e
7140-444: The full-scale articulated mannequin (more properly known as lay figure) as an aid in drawing and painting draped figures. In 18th-century England, lay-figures are known to have been owned by portrait painters such as Joshua Reynolds , Thomas Gainsborough , and Arthur Devis for the arrangement of conversation pieces . Anatomical models such as ivory manikins were used by doctors in the 17th century to study medical anatomy and as
7245-432: The gel. This techniques does underestimate true genetic variability as there may be an amino acid substitution but if the amino acid is not charged differently than the original no difference in migration will appear it is estimated that approximately 1/3 of the true genetic variation is not expressed by this technique. Structural variation , which can include insertions, deletions, duplications, and mutations in DNA. Within
7350-452: The human population, about 13% of the human genome is defined as structurally variant. Phenotypic variation , which accounts for both genetic and epigenetic factors that affect what characteristics are shown. For applications such as organ donations and matching, phenotypic variation of blood type, tissue type, and organ size are considered. Measurement of human variation may also be initiated by governmental parties. A government may conduct
7455-422: The larynx. The lower respiratory tract is also called the respiratory tree or tracheobronchial tree , to describe the branching structure of airways supplying air to the lungs, and includes the trachea, bronchi and bronchioles. At each division point or generation , one airway branches into two smaller airways. The human respiratory tree may consist on average of 23 generations, while the respiratory tree of
7560-403: The left of the midline. The right lung has three lobes – upper, middle, and lower (or superior, middle, and inferior), and the left lung has two – upper and lower (or superior and inferior), plus a small tongue-shaped portion of the upper lobe known as the lingula. Each lobe is further divided up into segments called bronchopulmonary segments . Each lung has a costal surface, which is adjacent to
7665-440: The lower respiratory tract or as separate entity and include the respiratory bronchioles, alveolar ducts , alveolar sacs , and alveoli . The respiratory tract can also be divided into a conducting zone and a respiratory zone , based on the distinction of transporting gases or exchanging them. The conducting zone includes structures outside of the lungs – the nose , pharynx , larynx , and trachea , and structures inside
7770-400: The lower respiratory tract. It is an inflammation of the bronchial tubes. There are two forms of this infection: acute bronchitis, which is treatable and can go away without treatment, or chronic bronchitis, which comes and goes, but will always affect one's lungs. Bronchitis increases the amount of mucus that is natural in your respiratory tract. Chronic bronchitis is common in smokers, because
7875-404: The lungs and an increased accumulation of carbon dioxide. There are two types of COPD: primary and secondary. Primary COPD can be found in younger adults. This type of COPD deteriorates the air sacs, and lung mass. Secondary COPD can be found in older adults who smoke or have smoked and have a history of bronchitis. COPD includes symptoms of emphysema and chronic bronchitis . The bronchi are
7980-438: The lungs and move into the air sacs. This infection quickly develops in the lower part of the lung and fills the lung with fluid, and excess mucus. This causes difficulty in breathing and coughing as the lower respiratory tract tries to get rid of the fluid in the lungs. You can be more prone to developing this infection if you have asthma, flu, heart disease, or cancer Bronchitis is another common infection that takes place in
8085-438: The lungs – the bronchi, bronchioles, and terminal bronchioles. The conduction zone conducts air breathed in that is filtered, warmed, and moistened, into the lungs. It represents the 1st through the 16th division of the respiratory tract. The conducting zone is most of the respiratory tract that conducts gases into and out of the lungs but excludes the respiratory zone that exchanges gases. The conducting zone also functions to offer
8190-425: The lungs. The inner ( visceral pleura ) covers the lungs and the outer ( parietal pleura ) lines the inner surface of the chest wall. This membrane secretes a small amount of fluid, allowing the lungs to move freely within the pleural cavity while expanding and contracting during breathing. The lungs are divided into different lobes. The right lung is larger in size than the left, because of the heart's being situated to
8295-469: The main passages to the right and left lungs. These airways carry oxygen to the bronchioles inside the lungs. Inflammation of the bronchii and bronchioles can cause them to swell up, which could lead to an asthma attack. This results in wheezing , tightness of the chest, and severe difficulty in breathing. There are different types of asthma that affect the functions of the bronchial tubes. Allergies can also set off an allergic reaction, causing swelling of
8400-414: The majority of people may be favorable in terms of biological factors. For example, women tend to have fewer pregnancies on average than before and therefore net worldwide fertility rates are dropping. Moreover, this leads to the fact that multiple births tend to be favorable in terms of number of children and therefore offspring count; when the average number of pregnancies and the average number of children
8505-404: The mannequin field and are built to withstand the hustle of customer foot traffic usually witnessed in the store they are placed in. Mannequins are used primarily by retail stores as in-store displays or window decoration. However, many online sellers also use them to display their products for their product photos (as opposed to using a live model). Renaissance artist Fra Bartolomeo invented
8610-460: The middle stage of the disease. It then starts to grow rashes all over the body, affecting people's human variation. Phenotypic variation is a combination of one's genetics and their surrounding environment, with no interaction or mutual influence between the two. This means that a significant portion of human variability can be controlled by human behavior. Nutrition and diet play a substantial role in determining phenotype because they are arguably
8715-414: The most common causes of an upper respiratory tract infection, which can cause more serious illness that can develop in the lower respiratory tract. Pneumonia is the most common, and frequent lower respiratory tract infection . This can be either viral, bacterial, or fungal. This infection is very common because pneumonia can be airborne, and when you inhale this infection in the air, the particles enter
8820-523: The most common infections in the world. The respiratory system is very prone to developing infections in the lungs. Infants and older adults are more likely to develop infections in their lungs because their lungs are not as strong in fighting off these infections. Most of these infections used to be fatal, but with new research and medicine, they are now treatable. With bacterial infections, antibiotics are prescribed, while viral infections are harder to treat but still curable. The common cold , and flu are
8925-529: The most controllable forms of environmental factors that create epigenetic changes. This is because they can be changed or altered relatively easily as opposed to other environmental factors like location. If people are reluctant to changing their diets, consuming harmful foods can have chronic negative effects on variability. One such instance of this occurs when eating certain chemicals through one's diet or consuming carcinogens, which can have adverse effects on individual phenotype. For example, Bisphenol A (BPA)
9030-661: The negatively valued or stigmatized ones, are usually considered an essential part of self-identity. Membership or status in a social group may depend on having specific values for certain attributes. It is not unusual for people to deliberately try to amplify or exaggerate differences, or to conceal or minimize them, for a variety of reasons. Examples of practices designed to minimize differences include tanning , hair straightening , skin bleaching , plastic surgery , orthodontia , and growth hormone treatment for extreme shortness. Conversely, male-female differences are enhanced and exaggerated in most societies. In some societies, such as
9135-428: The nose to the bronchioles is covered in ciliated pseudostratified columnar epithelium , commonly called respiratory epithelium . The cilia beat in one direction, moving mucus towards the throat where it is swallowed. Moving down the bronchioles, the cells get more cuboidal in shape but are still ciliated. Glands are abundant in the upper respiratory tract, but there are fewer lower down and they are absent starting at
9240-543: The origins of differences in alleles between individuals. However, mutations may also occur within a person's life-time and be passed down from parent to offspring. In some cases, mutations may result in genetic diseases, such as Cystic Fibrosis , which is the result of a mutation to the CFTR gene that is recessively inherited from both parents. In other cases, mutations may be harmless or phenotypically unnoticeable. We are able to treat biological traits as manifestations of either
9345-451: The process of breathing . Unlike the trachea and bronchi , the upper airway is a collapsible, compliant tube. As such, it has to be able to withstand suction pressures generated by the rhythmic expansion of the thoracic cavity that sucks air into the lungs. This is accomplished by the contraction of upper airway muscles during inhalation, such as the genioglossus (tongue) and the hyoid muscles. In addition to rhythmic innervation from
9450-459: The purview of several scholarly disciplines, many of which lie at the intersection of biology and statistics . The methods of biostatistics , the application of statistical methods to the analysis of biological data, and bioinformatics , the application of information technologies to the analysis of biological data, are utilized by researchers in these fields to uncover significant patterns of variability. Some fields of scientific research include
9555-461: The real world as people. In the Doctor Who serial Spearhead from Space (1970), an alien intelligence attempts to take over Earth with killer plastic mannequins called Autons . The romantic comedy film Mannequin (1987) is a story of a window dresser who falls in love with a mannequin that comes to life. The romantic thriller film Bommai (2023) is the story of a person who works in
9660-540: The reason homosexuality has not been eradicated by natural selection. Gay or lesbian individuals have not been greatly affected by evolutionary selection because they may help the fitness of their siblings and siblings' children, thus increasing their own fitness through inclusive fitness and maintaining evolution of homosexuality. Biological theories for same gender sexual orientation include genetic influences, neuroanatomical factors, and hormone differences but research so far has not provided any conclusive results. In contrast,
9765-411: The respiratory tract exists merely as a piping system for air to travel in the lungs, and alveoli are the only part of the lung that exchanges oxygen and carbon dioxide with the blood . Respiration is the rhythmical process of breathing , in which air is drawn into the alveoli of the lungs via inhalation and subsequently expelled via exhalation . When a human being inhales, air travels down
9870-460: The respiratory tract. They also increase the surface area for particle deposition, improving the nose's ability to filter pathogens. The cough reflex expels all irritants within the mucous membrane to the outside. The airways of the lungs contain rings of muscle. When the passageways are irritated by some allergen, these muscles can constrict. The respiratory tract is a common site for infections. Upper respiratory tract infections are probably
9975-423: The results of the mechanisms of recombination and crossing over . The ability of genes to be expressed may also be a source of variation between individuals and result in changes to phenotype. This may be the result of epigenetics , which are founded upon an organism's phenotypic plasticity , with such a plasticity even being heritable . Epigenetics may result from methylation of gene sequences leading to
10080-404: The ribcage; a diaphragmatic surface, which faces downward toward the diaphragm; and a mediastinal surface, which faces toward the center of the chest, and lies against the heart, great vessels, and the carina where the two mainstem bronchi branch off from the base of the trachea. The alveoli are tiny air sacs in the lungs where gas exchange takes place. The mean number of alveoli in a human lung
10185-435: The social constructivist position argues that sexuality is a result of culture and has originated from language or dialogue about sex. Mating choices are the product of cultural values, such as youth and attractiveness, and homosexuality varies greatly between cultures and societies. In this view, complexities, such as sexual orientation changing during the course of one's lifespan, are accounted for. Controversy also surrounds
10290-409: The soldiers. A Central Intelligence Agency (CIA) report describes the use of a mannequin ("Jack-in-the-Box") as a countersurveillance measure, intended to make it more difficult for the host country's counterintelligence to track the movement of CIA agents posing as diplomats. A "Jack-in-the-Box" – a mannequin representing the upper half of a human – would quickly replace a CIA agent after he left
10395-409: The tar from smoking accumulates over time, causing the lungs to work harder to repair themselves. Tuberculosis is one of many other infections that occurs in the lower respiratory tract. You can contract this infection from airborne droplets, and if inhaled you are at risk of this disease. This is a bacterial infection that deteriorates the lung tissue resulting in coughing up blood. This infection
10500-418: The trachea, through the bronchial tubes, and into the lungs. The entire tract is protected by the rib cage, spine , and sternum . In the lungs, oxygen from the inhaled air is transferred into the blood and circulated throughout the body. Carbon dioxide (CO 2 ) is transferred from returning blood back into gaseous form in the lungs and exhaled through the lower respiratory tract and then the upper, to complete
10605-610: The underlying genetic distribution of a population. We can model genetic drift with the Wright-Fisher model. In a population of N with 2N genes, there are two alleles with frequencies p and q. If the previous generation had an allele with frequency p, then the probability that the next generation has k of that allele is: ( 2 N k ) p k q 2 N − k {\displaystyle {2N \choose k}p^{k}q^{2N-k}} Over time, one allele will be fixed when
10710-457: The woman undergoes one pregnancy (in this case couple 2 has triplets). When the proportion of offspring count in the latter hypothetical scenario is compared, the difference in proportion of offspring count becomes higher. A trait in women known to greatly increase the chance of multiple births is being a tall woman (presumably the chance is further increased when the woman is very tall among both women and men). Yet very tall women are not viewed as
10815-539: Was higher, multiple births made only a slight relative difference in number of children. However, with fewer pregnancies, multiple births can make the difference in number of children relatively large. A hypothetical scenario would be that couple 1 has ten children and couple 2 has eight children, but in both couples, the woman undergoes eight pregnancies. This is not a large difference in ratio of fertility. However, another hypothetical scenario can be that couple 1 has three children and couple 2 has one child but in both couples
10920-596: Was in terms of logistics the easiest region to import reed dolls from, as the rivers Schelde and Oise provided easy routes from Flanders to Paris. As the Flemish wrote ' manneke(n) ' for 'little man' on their invoices, the Parisians pronounced this as 'mannequen', hence shifted to 'mannequin'. A mannequin is thus linguistically masculine, not feminine. Shop mannequins are derived from dress forms used by fashion houses for dress making. The use of mannequins originated in
11025-431: Was possible to deny that deafness is a disability. Another example of social renegotiation of the value assigned to a difference is reflected in the controversy over management of ambiguous genitalia , especially whether abnormal genital structure has enough negative consequences to warrant surgical correction. Furthermore, many genetic traits may be advantageous in certain circumstances and disadvantageous in others. Being
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