A cladogram (from Greek clados "branch" and gramma "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed, so many differing evolutionary trees can be consistent with the same cladogram. A cladogram uses lines that branch off in different directions ending at a clade , a group of organisms with a last common ancestor . There are many shapes of cladograms but they all have lines that branch off from other lines. The lines can be traced back to where they branch off. These branching off points represent a hypothetical ancestor (not an actual entity) which can be inferred to exhibit the traits shared among the terminal taxa above it. This hypothetical ancestor might then provide clues about the order of evolution of various features, adaptation, and other evolutionary narratives about ancestors. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational phylogenetics are now very commonly used in the generation of cladograms, either on their own or in combination with morphology.
68-461: A pig is a mammal of the genus Sus . Pig , PIG , Pigs or PIGS may also refer to: Pig The pig ( Sus domesticus ), also called swine ( pl. : swine) or hog , is an omnivorous , domesticated , even-toed, hoofed mammal . It is named the domestic pig when distinguishing it from other members of the genus Sus . It is considered a subspecies of Sus scrofa (the wild boar or Eurasian boar) by some authorities, but as
136-446: A t e s {\displaystyle n.states} , c i occupies a range from 1 to ( n . s t a t e s − 1 ) / ( n . t a x a − ⌈ n . t a x a / n . s t a t e s ⌉ ) {\displaystyle (n.states-1)/(n.taxa-\lceil n.taxa/n.states\rceil )} . The retention index (RI)
204-445: A metric to measure how consistent a candidate cladogram is with the data. Most cladogram algorithms use the mathematical techniques of optimization and minimization. In general, cladogram generation algorithms must be implemented as computer programs, although some algorithms can be performed manually when the data sets are modest (for example, just a few species and a couple of characteristics). Some algorithms are useful only when
272-537: A character in a phylogenetic analysis as they do not contribute anything to our understanding of relationships. However, homoplasy is often not evident from inspection of the character itself (as in DNA sequence, for example), and is then detected by its incongruence (unparsimonious distribution) on a most-parsimonious cladogram. Note that characters that are homoplastic may still contain phylogenetic signal . A well-known example of homoplasy due to convergent evolution would be
340-422: A dataset, the degree to which each character carries phylogenetic information, and the fashion in which additive characters are coded, rendering it unfit for purpose. c i occupies a range from 1 to 1/[ n.taxa /2] in binary characters with an even state distribution; its minimum value is larger when states are not evenly spread. In general, for a binary or non-binary character with n . s t
408-606: A distinct species by others. Pigs were domesticated in the Neolithic , both in East Asia and in the Near East. When domesticated pigs arrived in Europe, they extensively interbred with wild boar but retained their domesticated features. Pigs are farmed primarily for meat, called pork . The animal's skin or hide is used for leather . China is the world's largest pork producer, followed by
476-488: A healthy, full-grown adult. Vietnamese Pot-bellied pigs, a miniature breed of pig , have been kept as pets in the United States, beginning in the latter half of the 20th century. Pigs are intelligent, social creatures. They are considered hypoallergenic and are known to do quite well with people who have the usual animal allergies. Since these animals are known to have a life expectancy of 15 to 20 years, they require
544-457: A larger clade. The incongruence length difference test (ILD) is a measurement of how the combination of different datasets (e.g. morphological and molecular, plastid and nuclear genes) contributes to a longer tree. It is measured by first calculating the total tree length of each partition and summing them. Then replicates are made by making randomly assembled partitions consisting of the original partitions. The lengths are summed. A p value of 0.01
612-453: A litter of piglets, once per year. By the nineteenth century, European piglets routinely double-farrowed, or bore two litters of piglets per year. It is unclear when this shift occurred. Pigs have a maximum life span of about 27 years. A characteristic of pigs which they share with carnivores is nest-building . Sows root in the ground to create depressions the size of their body, and then build nest mounds, using twigs and leaves, softer in
680-466: A long snout strengthened by a special prenasal bone and a disk of cartilage at the tip. The snout is used to dig into the soil to find food and is an acute sense organ. The dental formula of adult pigs is 3.1.4.3 3.1.4.3 , giving a total of 44 teeth . The rear teeth are adapted for crushing. In males, the canine teeth can form tusks , which grow continuously and are sharpened by grinding against each other. There are four hoofed toes on each foot;
748-534: A long-term commitment. Given pigs are bred primarily as livestock and have not been bred as companion animals for very long, selective breeding for a placid or biddable temperament is not well established. Pigs have radically different psychology and behaviours compared to dogs, and exhibit fight-or-flight instincts, an independent nature, and natural assertiveness . Male and female swine that have not been de-sexed may express unwanted aggressive behavior, and are prone to developing serious health issues. As rooting
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#1732855762186816-452: A more and more popular way to infer phylogenetic hypotheses. Using a parsimony criterion is only one of several methods to infer a phylogeny from molecular data. Approaches such as maximum likelihood , which incorporate explicit models of sequence evolution, are non-Hennigian ways to evaluate sequence data. Another powerful method of reconstructing phylogenies is the use of genomic retrotransposon markers , which are thought to be less prone to
884-455: A now extinct ghost population of wild pigs during the Pleistocene . The genomes of domestic pigs show strong selection for genes affecting behavior and morphology. Human selection for domestic traits likely counteracted the homogenizing effect of gene flow from wild boars and created domestication islands in the genome. Pigs arrived in Europe from the Near East at least 8,500 years ago. Over
952-666: A separate species. Archaeological evidence shows that pigs were domesticated from wild boar in the Near East in or around the Tigris Basin, being managed in a semi-wild state much as they are managed by some modern New Guineans. There were pigs in Cyprus more than 11,400 years ago, introduced from the mainland, implying domestication in the adjacent mainland by then. Pigs were separately domesticated in China, starting some 8,000 years ago. In
1020-468: A short time and then sleep for a short time. Pigs are omnivorous and versatile in their feeding behaviour. They primarily eat leaves, stems, roots, fruits, and flowers. Rooting is an instinctual comforting behaviour in pigs characterized by nudging the snout into something. It first happens when piglets are born to obtain their mother's milk, and can become a habitual, obsessive behaviour, most prominent in animals weaned too early. Pigs root and dig into
1088-403: A shoulder height of 1.5 m (4 ft 11 in). Pigs possess both apocrine and eccrine sweat glands , although the latter are limited to the snout. Pigs, like other "hairless" mammals such as elephants, do not use thermal sweat glands in cooling. Pigs are less able than many other mammals to dissipate heat from wet mucous membranes in the mouth by panting. Their thermoneutral zone
1156-456: A simplified, crowded, or uncomfortable environment may resort to tail-biting ; farmers sometimes dock the tails of pigs to prevent the problem, or may enrich the environment with toys or other objects to reduce the risk. Because of their relative lack of sweat glands, pigs often control their body temperature using behavioural thermoregulation. Wallowing , coating the body with mud, is a common behaviour. They do not submerge completely under
1224-488: A target on screen. Pigs have panoramic vision of approximately 310° and binocular vision of 35° to 50°. It is thought they have no eye accommodation . Other animals that have no accommodation, e.g. sheep, lift their heads to see distant objects. The extent to which pigs have colour vision is still a source of some debate; however, the presence of cone cells in the retina with two distinct wavelength sensitivities (blue and green) suggests that at least some colour vision
1292-414: A teat, the more milk that teat later releases. In pigs, dominance hierarchies are formed at an early age. Piglets are precocious, and attempt to suckle soon after being born. The piglets are born with sharp teeth and fight for the anterior teats, as these produce more milk. Once established, this teat order remains stable; each piglet tends to feed on a particular teat or group of teats. Stimulation of
1360-481: A year, usually in spring or early summer, to prepare for the warmer months ahead. Where pigs are allowed to roam freely, they walk roughly 4 km daily, scavenging within a home range of around a hectare. Farmers in Africa often choose such a low-input, free-range production system. If conditions permit, pigs feed continuously for many hours and then sleep for many hours, in contrast to ruminants , which tend to feed for
1428-499: Is 16–22 °C (61–72 °F). At higher temperatures, pigs lose heat by wallowing in mud or water via evaporative cooling, although it has been suggested that wallowing may serve other functions, such as protection from sunburn, ecto-parasite control, and scent-marking. Pigs are among four mammalian species with mutations in the nicotinic acetylcholine receptor that protect against snake venom . Mongooses , honey badgers , hedgehogs , and pigs all have different modifications to
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#17328557621861496-410: Is a character state that is shared by two or more taxa due to some cause other than common ancestry. The two main types of homoplasy are convergence (evolution of the "same" character in at least two distinct lineages) and reversion (the return to an ancestral character state). Characters that are obviously homoplastic, such as white fur in different lineages of Arctic mammals, should not be included as
1564-475: Is especially an issue in southeastern South America. Female pigs reach sexual maturity at 3–12 months of age and come into estrus every 18–24 days if they are not successfully bred. The variation in ovulation rate can be attributed to intrinsic factors such as age and genotype, as well as extrinsic factors like nutrition, environment, and the supplementation of exogenous hormones. The gestation period averages 112–120 days. Estrus lasts two to three days, and
1632-420: Is found to be comforting, pigs kept in the house may root household objects, furniture or surfaces. Pet pigs should be let outside to allow them to fulfill their natural desire of rooting around. Approximately 1.5 billion pigs are slaughtered each year for meat. The pork belly futures contract became an icon of commodities trading . It appears in depictions of the arena in popular entertainment, such as
1700-450: Is most often considered to be a subspecies of the wild boar , which was given the name Sus scrofa by Carl Linnaeus in 1758; following from this, the formal name of the pig is Sus scrofa domesticus . However, in 1777, Johann Christian Polycarp Erxleben classified the pig as a separate species from the wild boar. He gave it the name Sus domesticus , still used by some taxonomists. The American Society of Mammalogists considers it
1768-411: Is obtained for 100 replicates if 99 replicates have longer combined tree lengths. Some measures attempt to measure the amount of homoplasy in a dataset with reference to a tree, though it is not necessarily clear precisely what property these measures aim to quantify The consistency index (CI) measures the consistency of a tree to a set of data – a measure of the minimum amount of homoplasy implied by
1836-400: Is present. Pigs have a well-developed sense of smell; this is exploited in Europe where trained pigs find underground truffles . Pigs have 1,113 genes for smell receptors, compared to 1,094 in dogs; this may indicate an acute sense of smell, but against this, insects have only around 50 to 100 such genes but make extensive use of olfaction. Olfactory rather than visual stimuli are used in
1904-526: Is usually done by comparison to the character states of one or more outgroups . States shared between the outgroup and some members of the in-group are symplesiomorphies; states that are present only in a subset of the in-group are synapomorphies. Note that character states unique to a single terminal (autapomorphies) do not provide evidence of grouping. The choice of an outgroup is a crucial step in cladistic analysis because different outgroups can produce trees with profoundly different topologies. A homoplasy
1972-611: The Midwest , where many state agencies have programs to remove them. Feral pigs in New Zealand and northern Queensland have caused substantial environmental damage. Feral hybrids of the European wild boar with the domestic pig are disruptive to both environment and agriculture, as they destroy crops, spread animal diseases including Foot-and-mouth disease , and consume wildlife such as juvenile seabirds and young tortoises . Feral pig damage
2040-455: The tick -borne African Swine Fever , bacterial infections such as Clostridium , arthritis caused by Mycoplasma , and stillbirths caused by Parvovirus . Some parasites of pigs are a public health risk as they can be transmitted to humans in undercooked pork. These are the pork tapeworm Taenia solium ; a protozoan, Toxoplasma gondii ; and a nematode, Trichinella spiralis . Transmission can be prevented by thorough sanitation on
2108-677: The 1983 film Trading Places . Trade in pork bellies declined, and they were delisted from the Chicago Mercantile Exchange in 2011. Cladogram The characteristics used to create a cladogram can be roughly categorized as either morphological (synapsid skull, warm blooded, notochord , unicellular, etc.) or molecular (DNA, RNA, or other genetic information). Prior to the advent of DNA sequencing, cladistic analysis primarily used morphological data. Behavioral data (for animals) may also be used. As DNA sequencing has become cheaper and easier, molecular systematics has become
Pig (disambiguation) - Misplaced Pages Continue
2176-462: The European Union and then the United States. Around 1.5 billion pigs are raised each year, producing some 120 million tonnes of meat, often cured as bacon . Some are kept as pets . Pigs have featured in human culture since Neolithic times, appearing in art and literature for children and adults, and celebrated in cities such as Bologna for their meat products. The pig has a large head, with
2244-478: The Near East, pig husbandry spread for the next few millennia. It reduced gradually during the Bronze Age , as rural populations instead focused on commodity-producing livestock, but it was sustained in cities. Domestication did not involve reproductive isolation with population bottlenecks. Western Asian pigs were introduced into Europe, where they crossed with wild boar. There appears to have been interbreeding with
2312-604: The Near Eastern genes dying out in European pig stock. More recently there have been complex exchanges, with European domesticated lines being exported, in turn, to the ancient Near East. Historical records indicate that Asian pigs were again introduced into Europe during the 18th and early 19th centuries. Among the animals that the Spanish introduced to the Chiloé Archipelago in the 16th century Columbian Exchange , pigs were
2380-553: The anterior teats appears to be important in causing milk letdown, so it might be advantageous to the entire litter to have these teats occupied by healthy piglets. Piglets locate teats by sight and then by olfaction. Pig behaviour is intermediate between that of other artiodactyls and of carnivores . Pigs seek out the company of other pigs and often huddle to maintain physical contact, but they do not naturally form large herds. They live in groups of about 8–10 adult sows, some young individuals, and some single males. Pigs confined in
2448-414: The boar's corkscrew-shaped penis during copulation. Females have bicornuate uteruses and two conceptuses must be present in both uterine horns to enable pregnancy to proceed. The mother's body recognises that it is pregnant on days 11 to 12 of pregnancy, and is marked by the corpus luteum 's producing the sex hormone progesterone . To sustain the pregnancy, the embryo signals to the corpus luteum with
2516-431: The character, "presence of wings". Although the wings of birds, bats , and insects serve the same function, each evolved independently, as can be seen by their anatomy . If a bird, bat, and a winged insect were scored for the character, "presence of wings", a homoplasy would be introduced into the dataset, and this could potentially confound the analysis, possibly resulting in a false hypothesis of relationships. Of course,
2584-434: The characteristic data are molecular (DNA, RNA); other algorithms are useful only when the characteristic data are morphological. Other algorithms can be used when the characteristic data includes both molecular and morphological data. Algorithms for cladograms or other types of phylogenetic trees include least squares , neighbor-joining , parsimony , maximum likelihood , and Bayesian inference . Biologists sometimes use
2652-685: The dataset). The rescaled consistency index (RC) is obtained by multiplying the CI by the RI; in effect this stretches the range of the CI such that its minimum theoretically attainable value is rescaled to 0, with its maximum remaining at 1. The homoplasy index (HI) is simply 1 − CI. This measures the amount of homoplasy observed on a tree relative to the maximum amount of homoplasy that could theoretically be present – 1 − (observed homoplasy excess) / (maximum homoplasy excess). A value of 1 indicates no homoplasy; 0 represents as much homoplasy as there would be in
2720-470: The domesticated pig is one of the most numerous large mammals on the planet. Like all animals, pigs are susceptible to adverse impacts from climate change , such as heat stress from increased annual temperatures and more intense heatwaves . Heat stress has increased rapidly between 1981 and 2017 on pig farms in Europe. Installing a ground-coupled heat exchanger is an effective intervention. Around 600 breeds of pig have been created by farmers around
2788-457: The farm; by meat inspection and careful commercial processing; and by thorough cooking, or alternatively by sufficient freezing and curing. Pigs have been raised outdoors, and sometimes allowed to forage in woods or pastures. In industrialized nations, pig production has largely switched to large-scale intensive pig farming . This has lowered production costs but has caused concern about possible cruelty . As consumers have become concerned with
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2856-417: The female's displayed receptiveness to mate is known as standing heat. Standing heat is a reflexive response that is stimulated when the female is in contact with the saliva of a sexually mature boar. Androstenol is one of the pheromones produced in the submaxillary salivary glands of boars that trigger the female's response. The female cervix contains a series of five interdigitating pads, or folds, that hold
2924-416: The flow stops and so does the grunting of the sow. The piglets may dart from teat to teat and recommence suckling with slow movements, or nosing the udder. Piglets massage and suckle the sow's teats after milk flow ceases as a way of letting the sow know their nutritional status. This helps her to regulate the amount of milk released from that teat in future sucklings. The more intense the post-feed massaging of
2992-464: The ground to forage for food. Rooting is also a means of communication. Pigs are relatively intelligent animals, roughly on par with dogs . They distinguish each other as individuals, spend time in play, and form structured communities. They have good long-term memory and they experience emotions, changing their behaviour in response to the emotional states of other pigs. In terms of experimental tasks, pigs can perform tasks that require them to identify
3060-446: The herd. This ensures they do not get trampled on, and prevents other piglets from stealing milk from the sow. The onset of nest-building is triggered by a rise in prolactin level, caused by a decrease in progesterone and an increase in prostaglandin; the gathering of nest material seems to be regulated more by external stimuli such as temperature. Pigs have complex nursing and suckling behaviour. Nursing occurs every 50–60 minutes, and
3128-480: The hormones estradiol and prostaglandin E2 . This signaling acts on both the endometrium and luteal tissue to prevent the regression of the corpus luteum by activation of genes that are responsible for corpus luteum maintenance. During mid to late pregnancy, the corpus luteum relies primarily on luteinizing hormone for maintenance until birth. Archeological evidence indicates that medieval European pigs farrowed, or bore
3196-458: The humane treatment of livestock, demand for pasture-raised pork in these nations has increased. Most pigs in the US receive ractopamine , a beta-agonist drug , which promotes muscle instead of fat and quicker weight gain, requiring less feed to reach finishing weight, and producing less manure . China has requested that pork exports be ractopamine-free. With a population of around 1 billion individuals,
3264-568: The identification of other pigs. Hearing is well developed; sounds are localised by moving the head. Pigs use auditory stimuli extensively for communication in all social activities. Alarm or aversive stimuli are transmitted to other pigs not only by auditory cues but also by pheromones . Similarly, recognition between the sow and her piglets is by olfactory and vocal cues. Pigs are subject to many pests and diseases which can seriously affect productivity and cause death. These include parasites such as Ascaris roundworms, virus diseases such as
3332-432: The locations of objects; they can solve mazes; and they can work with a simple language of symbols. They display self-recognition in a mirror . Pigs have been trained to associate different sorts of music (Bach and a military march) with food and social isolation respectively, and could communicate the resulting positive or negative emotion to untrained pigs. Pigs can be trained to use a joystick with their snout to select
3400-399: The middle, in which to give birth. When the mound reaches the desired height, she places large branches, up to 2 metres in length, on the surface. She enters the mound and roots around to create a depression within the gathered material. She then gives birth in a lying position, unlike other artiodactyls which usually stand while birthing. Nest-building occurs during the last 24 hours before
3468-443: The most successful in adapting to local conditions. The pigs benefited from abundant shellfish and algae exposed by the large tides of the archipelago. Pigs were brought to southeastern North America from Europe by de Soto and other early Spanish explorers . Escaped pigs became feral . Pigs have escaped from farms and gone feral in many parts of the world. Feral pigs in the southeastern United States have migrated north to
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#17328557621863536-405: The mud, but vary the depth and duration of wallowing depending on environmental conditions. Adult pigs start wallowing once the ambient temperature is around 17–21 °C (63–70 °F). They cover themselves in mud from head to tail. They may use mud as a sunscreen, or to keep parasites away. Most bristled pigs "blow their coat", meaning that they shed most of the longer, coarser stiff hair once
3604-431: The next 3,000 years they interbred with European wild boar until their genome showed less than 5% Near Eastern ancestry, yet retained their domesticated features. DNA evidence from subfossil remains of teeth and jawbones of Neolithic pigs shows that the first domestic pigs in Europe were brought from the Near East. This stimulated the domestication of local European wild boar, resulting in a third domestication event with
3672-705: The only reason a homoplasy is recognizable in the first place is because there are other characters that imply a pattern of relationships that reveal its homoplastic distribution. A cladogram is the diagrammatic result of an analysis, which groups taxa on the basis of synapomorphies alone. There are many other phylogenetic algorithms that treat data somewhat differently, and result in phylogenetic trees that look like cladograms but are not cladograms. For example, phenetic algorithms, such as UPGMA and Neighbor-Joining, group by overall similarity, and treat both synapomorphies and symplesiomorphies as evidence of grouping, The resulting diagrams are phenograms, not cladograms, Similarly,
3740-402: The onset of farrowing, and becomes most intense 12 to 6 hours before farrowing. The sow separates from the group and seeks a suitable nest site with well-drained soil and shelter from rain and wind. This provides the offspring with shelter, comfort, and thermoregulation. The nest provides protection against weather and predators, while keeping the piglets close to the sow and away from the rest of
3808-499: The problem of reversion that plagues sequence data. They are also generally assumed to have a low incidence of homoplasies because it was once thought that their integration into the genome was entirely random; this seems at least sometimes not to be the case, however. Researchers must decide which character states are "ancestral" ( plesiomorphies ) and which are derived ( synapomorphies ), because only synapomorphic character states provide evidence of grouping. This determination
3876-436: The program settles on a local minimum rather than the desired global minimum. To help solve this problem, many cladogram algorithms use a simulated annealing approach to increase the likelihood that the selected cladogram is the optimal one. The basal position is the direction of the base (or root) of a rooted phylogenetic tree or cladogram. A basal clade is the earliest clade (of a given taxonomic rank[a]) to branch within
3944-795: The receptor pocket which prevents α-neurotoxin from binding. Pigs have small lungs for their body size, and are thus more susceptible than other domesticated animals to fatal bronchitis and pneumonia . The genome of the pig has been sequenced; it contains about 22,342 protein -coding genes . Domestic pigs are related to other pig species as shown in the cladogram , based on phylogenetic analysis using mitochondrial DNA . Babirusa [REDACTED] Red river hog [REDACTED] Warthogs [REDACTED] Visayan warty pig [REDACTED] Philippine warty pig [REDACTED] Bornean bearded pig [REDACTED] Javan warty pig [REDACTED] [REDACTED] East Asian pigs [REDACTED] European pigs [REDACTED] The pig
4012-405: The results of model-based methods (Maximum Likelihood or Bayesian approaches) that take into account both branching order and "branch length," count both synapomorphies and autapomorphies as evidence for or against grouping, The diagrams resulting from those sorts of analysis are not cladograms, either. There are several algorithms available to identify the "best" cladogram. Most algorithms use
4080-469: The sow grunts at slow, regular intervals. Each series of grunts varies in frequency, tone and magnitude, indicating the stages of nursing to the piglets. The phase of competition for teats and of nosing the udder lasts for about a minute, ending when milk begins to flow. The piglets then hold the teats in their mouths and suck with slow mouth movements (one per second), and the rate of the sow's grunting increases for approximately 20 seconds. The grunt peak in
4148-406: The sow requires stimulation from piglets before milk let-down. Sensory inputs (vocalisation, odours from mammary and birth fluids, and hair patterns of the sow) are particularly important immediately post-birth to facilitate teat location by the piglets. Initially, the piglets compete for position at the udder; then the piglets massage around their respective teats with their snouts, during which time
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#17328557621864216-460: The term parsimony for a specific kind of cladogram generation algorithm and sometimes as an umbrella term for all phylogenetic algorithms. Algorithms that perform optimization tasks (such as building cladograms) can be sensitive to the order in which the input data (the list of species and their characteristics) is presented. Inputting the data in various orders can cause the same algorithm to produce different "best" cladograms. In these situations,
4284-452: The third phase of suckling does not coincide with milk ejection, but rather the release of oxytocin from the pituitary into the bloodstream. Phase four coincides with the period of main milk flow (10–20 seconds) when the piglets suddenly withdraw slightly from the udder and start sucking with rapid mouth movements of about three per second. The sow grunts rapidly, lower in tone and often in quick runs of three or four, during this phase. Finally,
4352-406: The tree. It is calculated by counting the minimum number of changes in a dataset and dividing it by the actual number of changes needed for the cladogram. A consistency index can also be calculated for an individual character i , denoted c i . Besides reflecting the amount of homoplasy, the metric also reflects the number of taxa in the dataset, (to a lesser extent) the number of characters in
4420-492: The two larger central toes bear most of the weight, while the outer two are also used in soft ground. Most pigs have rather sparsely bristled hair on their skin, though there are some woolly -coated breeds such as the Mangalitsa . Adult pigs generally weigh between 140 and 300 kg (310 and 660 lb), though some breeds can exceed this range. Exceptionally, a pig called Big Bill weighed 1,157 kg (2,551 lb) and had
4488-423: The user should input the data in various orders and compare the results. Using different algorithms on a single data set can sometimes yield different "best" cladograms, because each algorithm may have a unique definition of what is "best". Because of the astronomical number of possible cladograms, algorithms cannot guarantee that the solution is the overall best solution. A nonoptimal cladogram will be selected if
4556-628: The world, mainly in Europe and Asia, differing in coloration, shape, and size. According to The Livestock Conservancy , as of 2016, three breeds of pig are critically rare (having a global population of fewer than 2000). They are the Choctaw hog , the Mulefoot , and the Ossabaw Island hog . The smallest known pig breed in the world is the Göttingen minipig , typically weighing about 26 kilograms (57 lb) as
4624-399: Was proposed as an improvement of the CI "for certain applications" This metric also purports to measure of the amount of homoplasy, but also measures how well synapomorphies explain the tree. It is calculated taking the (maximum number of changes on a tree minus the number of changes on the tree), and dividing by the (maximum number of changes on the tree minus the minimum number of changes in
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