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Neoavian
Neoaves is a clade that consists of all modern birds (Neornithes or Aves) with the exception of Palaeognathae (ratites and kin) and Galloanserae (ducks, chickens and kin). This group is defined in the ''PhyloCode'' by George Sangster and colleagues in 2022 as "the most inclusive crown clade containing ''Passer domesticus'', but not ''Gallus gallus''". Almost 95% of the roughly 10,000 known species of extant birds belong to the Neoaves. The early diversification of the various neoavian groups occurred very rapidly around the Cretaceous–Paleogene extinction event, and attempts to resolve their relationships with each other have resulted initially in much controversy. Phylogeny The early diversification of the various neoavian groups occurred very rapidly around the Cretaceous–Paleogene extinction event. As a result of the rapid radiation, attempts to resolve their relationships have produced conflicting results, some quite controversial, especially in the earlier studies.Matzk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gruiformes
The Gruiformes ( ) are an order containing a considerable number of living and extinct bird families, with a widespread geographical diversity. Gruiform means "crane-like". Traditionally, a number of wading and terrestrial bird families that did not seem to belong to any other order were classified together as Gruiformes. These include 15 species of large cranes, about 145 species of smaller crakes and rails, as well as a variety of families comprising one to three species, such as the Heliornithidae, the limpkin, or the Psophiidae. Other birds have been placed in this order more out of necessity to place them ''somewhere''; this has caused the expanded Gruiformes to lack distinctive apomorphies. Recent studies indicate that these "odd Gruiformes" are if at all only loosely related to the cranes, rails, and relatives ("core Gruiformes"). Systematics There are only two suprafamilial clades (natural groups) among the birds traditionally classified as Gruiformes. Rails ( Ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleocene
The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name is a combination of the Ancient Greek ''palaiós'' meaning "old" and the Eocene Epoch (which succeeds the Paleocene), translating to "the old part of the Eocene". The epoch is bracketed by two major events in Earth's history. The K–Pg extinction event, brought on by an asteroid impact (Chicxulub impact) and possibly volcanism (Deccan Traps), marked the beginning of the Paleocene and killed off 75% of species, most famously the non-avian dinosaurs. The end of the epoch was marked by the Paleocene–Eocene Thermal Maximum (PETM), which was a major climatic event wherein about 2,500–4,500 gigatons of carbon were released into the atmosphere and ocean systems, causing a spike in global temperatures and ocean acidification. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telluraves
Telluraves (also called land birds or core landbirds) is a recently defined clade of birds defined by their arboreality. Based on most recent genetic studies, the clade unites a variety of bird groups, including the australavians (passerines, parrots, seriemas, and falcons) as well as the afroavians (including the Accipitrimorphae – eagles, hawks, buzzards, vultures etc. – owls and woodpeckers, among others). This grouping was defined in the ''PhyloCode'' by George Sangster and colleagues in 2022 as "the least inclusive crown clade containing '' Accipiter nisus'' and '' Passer domesticus''". They appear to be the sister group of the Phaethoquornithes. Given that the most basal extant members of both Afroaves (Accipitrimorphae, Strigiformes) and Australaves (Cariamiformes, Falconiformes) are birds of prey, it has been suggested that the last common ancestor of all Telluraves may have been an apex predator, and possibly also a bird of prey. Other researchers are ske ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Clock
The molecular clock is a figurative term for a technique that uses the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged. The biomolecular data used for such calculations are usually nucleotide sequences for DNA, RNA, or amino acid sequences for proteins. Early discovery and genetic equidistance The notion of the existence of a so-called "molecular clock" was first attributed to Émile Zuckerkandl and Linus Pauling who, in 1962, noticed that the number of amino acid differences in hemoglobin between different lineages changes roughly linearly with time, as estimated from fossil evidence. They generalized this observation to assert that the rate of evolutionary change of any specified protein was approximately constant over time and over different lineages (known as the molecular clock hypothesis). The genetic equidistance phenomenon was first noted in 1963 by Emanuel Margoliash, who wrote: "It appears that the number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a four-chambered heart, and a strong yet lightweight Bird skeleton, skeleton. Birds live worldwide and range in size from the bee hummingbird to the common ostrich. There are over 11,000 living species and they are split into 44 Order (biology), orders. More than half are passerine or "perching" birds. Birds have Bird wing, wings whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the Flightless bird, loss of flight in some birds, including ratites, penguins, and diverse endemism, endemic island species. The digestive and respiratory systems of birds are also uniquely a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurypygimorphae
Eurypygimorphae or Phaethontimorphae is a clade of birds that contains the orders Phaethontiformes (tropicbirds) and Eurypygiformes (kagu and sunbittern) recovered by genome analysis. The relationship was first identified in 2013 based on their nuclear genes. This group was defined in the ''PhyloCode'' by George Sangster and colleagues in 2022 as "the least inclusive crown clade containing '' Phaethon aethereus'', ''Eurypyga helias The sunbittern (''Eurypyga helias'') is a bittern-like bird of tropical regions of the Americas, and the Monotypic taxon, sole member of the family (biology), family Eurypygidae (sometimes spelled Eurypigidae) and genus ''Eurypyga''. It is found ...'', and '' Rhynochetos jubatus''". Historically these birds were placed at different parts of the tree, with tropicbirds in Pelecaniformes and the kagu and sunbittern in Gruiformes. Some genetic analyses have placed the eurypygimorph taxa in the controversial and obsolete clade Metaves, with uncertai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aequornithes
Aequornithes (, from Latin ''aequor'', expanse of water + Greek ''ornithes'', birds), or core water birds, are defined in the ''PhyloCode'' as "the least inclusive crown clade containing '' Pelecanus onocrotalus'' and '' Gavia immer''", that is, the last common ancestor of the great white pelican and the common loon, as well as its descendants, extinct and extant. The monophyly of the group is currently supported by several molecular phylogenetic studies. Aequornithes includes the clades Gaviiformes, Sphenisciformes, Procellariiformes, Ciconiiformes, Suliformes and Pelecaniformes. It does not include several unrelated groups of aquatic birds such as flamingos and grebes ( Mirandornithes), shorebirds, gulls, and auks (Charadriiformes), or the Anseriformes (waterfowl). Based on a whole-genome analysis of the bird orders, the kagu and sunbittern ( Eurypygiformes) and the three species of tropicbirds ( Phaethontiformes) together styled as the Eurypygimorphae are the closest s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polytomy
An internal node of a phylogenetic tree is described as a polytomy or multifurcation if (i) it is in a rooted tree and is linked to three or more child subtrees or (ii) it is in an unrooted tree and is attached to four or more branches. A tree that contains any multifurcations can be described as a multifurcating tree. Soft polytomies vs. hard polytomies Two types of polytomies are recognized, soft and hard polytomies. Soft polytomies are the result of insufficient phylogenetic information: though the lineages diverged at different times – meaning that some of these lineages are closer relatives than others, and the available data does not allow recognition of this. Most polytomies are soft, meaning that they would be resolved into a typical tree of dichotomies if better data were available. In contrast, a hard polytomy represents a true divergence event of three or more lineages. Applications Interpretations for a polytomy depend on the individuals that are represented ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Passerea
Passerea is a clade of Neoaves, neoavian birds that was proposed by Jarvis ''et al''. (2014). Their genomic analysis recovered two major clades within Neoaves, Passerea and Columbea, and concluded that both clades appear to have many ecologically driven convergent traits. According to Jarvis (2014), these convergences include the foot-propelled diving trait of grebes in Columbea with loons and cormorants in Passerea; the wading-feeding trait of flamingos in Columbea with ibises and egrets in Passerea; and pigeons and sandgrouse in Columbea with shorebirds (killdeer) in Passerea. For Jarvis (2014), these long-known trait and morphological alliances suggest that some of the traditional nongenomic trait classifications are based on Polyphyly, polyphyletic assemblages. Passerea was not recovered in other studies. Phylogeny Cladogram of Passerea relationships based on Jarvis ''et al.'' (2014) with some clade names after Yuri ''et al.'' (2013) and Kimball ''et al.'' 2013. The fol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columbea
Columbea is a clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ... suggested by genome analysis that contains Columbiformes (pigeons and doves), Pteroclidae (sandgrouse), Mesitornithidae (mesites) and Mirandornithes (flamingos and grebes). Until their recent placement as the sister taxon to Passerea, in the last decade various genetic analysis found them to be in the obsolete clade Metaves. References Neognathae Tetrapod unranked clades {{bird-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous–Paleogene Extinction Event
The Cretaceous–Paleogene (K–Pg) extinction event, also known as the K–T extinction, was the extinction event, mass extinction of three-quarters of the plant and animal species on Earth approximately 66 million years ago. The event caused the extinction of all non-avian dinosaurs. Most other tetrapods weighing more than also became extinct, with the exception of some ectothermic species such as sea turtles and crocodilians. It marked the end of the Cretaceous period, and with it the Mesozoic era, while heralding the beginning of the current era, the Cenozoic. In the geologic record, the K–Pg event is marked by a thin layer of sediment called the Cretaceous–Paleogene boundary, K–Pg boundary or K–T boundary, which can be found throughout the world in marine and terrestrial rocks. The boundary clay shows unusually high levels of the metal iridium, which is more common in asteroids than in the Earth's crust. As originally proposed in 1980 by a team of scientists le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biology Letters
''Biology Letters'' is a peer-reviewed scientific journal published by the Royal Society, established in 2005. It focuses on the rapid publication of short research articles, reviews, and opinion pieces across the biological sciences. The editor-in-chief is David Beerling FRS (University of Sheffield). Contents As well as conventional short research articles, the journal has recently published ''Special Features'' and ''Mini Series''. Special Features are collections of up to 20 articles on a specific theme and published across multiple issues. Mini Series include up to six articles that are published in one issue. History The journal was split off from the '' Proceedings of the Royal Society B: Biological Sciences'' in 2005 after having been published as a supplement. Originally it was published quarterly, then bimonthly, and since 2013 it has been published monthly. Printing ceased at the start of 2020. Abstracting and indexing The journal is abstracted and indexed in: Accord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
