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.
41-430: N. phaeopus N. hudsonicus † N. tenuirostris N. arquata N. americanus N. madagascariensis N. minutus †(?) N. borealis N. tahitiensis Palnumenius Miller , 1942 The curlews ( / ˈ k ɜːr lj uː / ) are a group of nine species of birds in the genus Numenius , characterised by their long, slender, downcurved bills and mottled brown plumage . The English name
82-446: 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)
123-445: 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
164-436: A bird mentioned by Hesychius . It is associated with the curlews because it appears to be derived from neos , "new" and mene "moon", referring to the crescent-shaped bill. The genus contains nine species: [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] The following cladogram shows
205-694: A central crown stripe and strong supercilia. The whimbrel is a migratory bird wintering on coasts in Africa , and South Asia into Australasia . It is also a coastal bird during migration . It is fairly gregarious outside the breeding season. It is found in Ireland and the United Kingdom, and it breeds in Scotland , particularly around Shetland , Orkney , the Outer Hebrides as well as
246-540: 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
287-422: 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
328-457: 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
369-452: 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
410-549: A result, whimbrel on vagrancy trips to North America may be known as the “white-rumped whimbrel”, while whimbrel vagrants from North America to Europe may be known as “Hudsonian whimbrel”. When the context of their location is known, both species may be simply known as the whimbrel. The Eurasian whimbrel is a fairly large wader, though mid-sized as a member of the curlew genus. It is 37–47 cm (15–19 in) in length, 75–90 cm (30–35 in) in wingspan, and 270–493 g (9.5–17.4 oz; 0.595–1.087 lb) in weight. It
451-410: 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
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#1732772247553492-619: Is imitative of the Eurasian curlew 's call, but may have been influenced by the Old French corliu , "messenger", from courir , "to run". It was first recorded in 1377 in Langland's Piers Plowman " Fissch to lyue in þe flode..Þe corlue by kynde of þe eyre ". In Europe , "curlew" usually refers to one species, the Eurasian curlew ( Numenius arquata ). They are one of the most ancient lineages of scolopacid waders , together with
533-470: Is imitative of the bird's call. Five subspecies are recognised: The Hudsonian curlew ( Numenius hudsonicus ) was formerly considered to be conspecific . The two species were split based on genetic and plumage differences. The common whimbrel was traditionally considered a sub-cosmopolitan bird, breeding in Russia and Canada, then migrating to coasts all around the world to spend the winter. However
574-647: Is listed in the Agreement on the Conservation of African-Eurasian Migratory Waterbirds . Near the end of the 19th century, hunting on the Eurasian whimbrel's migration routes took a heavy toll on its population, which has since recovered. It is listed as Least Concern on the IUCN Red List and has been negatively impacted by climate change, habitat destruction and outbreaks of Avian flu to which it
615-400: Is mainly greyish brown, with a white back and rump (subspecies N. p. phaeopus and N. p. alboaxillaris only), and a long curved beak with a kink rather than a smooth curve. The usual call is a rippling whistle, prolonged into a trill for the song. The only similar common species over most of this bird's range are larger curlews. The whimbrel is smaller, has a shorter, decurved bill and has
656-411: 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
697-620: Is susceptible. The whimbrel and the Hudsonian curlew are considered to be conspecific . 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
738-526: 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
779-518: The Hudsonian whimbrel have recently been split, although some taxonomic authorities still consider them to be conspecific. The Eurasian whimbrel was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae under the binomial name Scolopax phaeopus . It is now placed with the curlews in the genus Numenius that was introduced by
820-642: The godwits which look similar but have straight bills. Curlews feed on mud or very soft ground, searching for worms and other invertebrates with their long bills. They will also take crabs and similar items. Curlews enjoy a worldwide distribution. Most species exhibit strong migratory habits and consequently one or more species can be encountered at different times of the year in Europe, Ireland , Britain , Iberia , Iceland , Africa , Southeast Asia , Siberia , North America , South America and Australasia . The distribution of curlews has altered considerably in
861-646: The French ornithologist Mathurin Jacques Brisson in 1760. The genus name Numenius is from Ancient Greek noumenios , a bird mentioned by Hesychius . It is associated with the curlews because it appears to be derived from neos , "new" and mene "moon", referring to the crescent-shaped bill. The specific epithet phaeopus is the Medieval Latin name for the bird, from Ancient Greek phaios , "dusky" and pous , "foot". The English name "whimbrel"
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#1732772247553902-594: The North American population of whimbrels was considered distinct enough to be considered a separate species from the common whimbrel. In 2020, the New World population was recognised as a separate species, with the whimbrel in North America being assigned to the binomial name Numenius hudsonicus . Whilst very similar at an initial glance, there are several features that distinguish whimbrel species in
943-477: The Old and New World. In appearance, the New World species has a more “faded” appearance, with differences in the supercilium and crown. By far the most significant difference may be seen in the lower half of the bird. Whimbrels in Europe and Asia have a primarily white rump that can be seen in flight, while whimbrel in the New World have a rump similar in colour to the rest of the bird - drab brown with dark streaking. As
984-431: 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,
1025-434: 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
1066-456: The curlews. It is distinguished from them by its yellow legs, long tail, and shorter, less curved bill. Eurasian whimbrel The Eurasian or common whimbrel ( Numenius phaeopus ), also known as the white-rumped whimbrel in North America, is a wader in the large family Scolopacidae . It is one of the most widespread of the curlews , breeding across much of subarctic Asia and Europe as far south as Scotland . This species and
1107-691: 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
1148-465: The family Burhinidae , which is in the same order Charadriiformes , but only distantly related within that. The genus Numenius was erected by the French scientist Mathurin Jacques Brisson in his Ornithologie published in 1760. The type species is the Eurasian curlew ( Numenius arquata ). The Swedish naturalist Carl Linnaeus had introduced the genus Numenius in the 6th edition of his Systema Naturae published in 1748, but Linnaeus dropped
1189-548: The genetic relationships between the species. It is based on a study published in 2023. Little curlew ( N. minutus ) Bristle-thighed curlew ( N. tahitiensis ) Eurasian whimbrel ( N. phaeopus ) Hudsonian whimbrel ( N. hudsonicus ) Long-billed curlew ( N. americanus ) Eskimo curlew ( N. borealis ) Far Eastern curlew ( N. madagascariensis ) Eurasian curlew ( N. arquata ) Slender-billed curlew ( N. tenuirostris ) The Late Eocene ( Montmartre Formation , some 35 mya) fossil Limosa gypsorum of France
1230-478: The genus in the important tenth edition of 1758 and put the curlews together with the woodcocks in the genus Scolopax . As the publication date of Linnaeus's sixth edition was before the 1758 starting point of the International Commission on Zoological Nomenclature , Brisson and not Linnaeus is considered as the authority for the genus. The name Numenius is from Ancient Greek noumenios ,
1271-516: The mainland at Sutherland and Caithness . The nest is a bare scrape on tundra or Arctic moorland. Three to five eggs are laid. Adults are very defensive of nesting area and will even attack humans who come too close. This species feeds by probing soft mud for small invertebrates and by picking small crabs and similar prey off the surface. Before migration, berries become an important part of their diet. It has also been observed taking insects, specifically blue tiger butterflies The whimbrel
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1312-705: 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,
1353-569: The past hundred years as a result of changing agricultural practices. For instance, Eurasian curlew populations have suffered due to draining of marshes for farmland, whereas long-billed curlews have shown an increase in breeding densities around areas grazed by livestock. As of 2019, there were only a small number of Eurasian curlews still breeding in Ireland, raising concerns that the bird will become extinct in that country. The stone-curlews are not true curlews (family Scolopacidae) but members of
1394-499: 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
1435-436: 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
1476-405: 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
1517-460: 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,
1558-406: 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
1599-423: 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
1640-477: Was originally placed in Numenius and may in fact belong there. Apart from that, a Late Pleistocene curlew from San Josecito Cave, Mexico has been described. This fossil was initially placed in a distinct genus , Palnumenius , but was actually a chronospecies or paleosubspecies related to the long-billed curlew . The upland sandpiper ( Bartramia longicauda ) is an odd bird which is the closest relative of
1681-399: 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