23-645: Columbea is a clade 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 . Phoenicopteriformes (flamingos) [REDACTED] Podicipediformes (grebes) [REDACTED] Columbiformes (pigeons and doves) [REDACTED] Pterocliformes (sandgrouse) [REDACTED] Mesitornithiformes (mesites) [REDACTED] This bird-related article
46-479: A "ladder", with supposedly more "advanced" organisms at the top. Taxonomists have increasingly worked to make the taxonomic system reflect evolution. When it comes to naming , this principle is not always compatible with the traditional rank-based nomenclature (in which only taxa associated with a rank can be named) because not enough ranks exist to name a long series of nested clades. For these and other reasons, phylogenetic nomenclature has been developed; it
69-623: A clade can be described based on two different reference points, crown age and stem age. The crown age of a clade refers to the age of the most recent common ancestor of all of the species in the clade. The stem age of a clade refers to the time that the ancestral lineage of the clade diverged from its sister clade. A clade's stem age is either the same as or older than its crown age. Ages of clades cannot be directly observed. They are inferred, either from stratigraphy of fossils , or from molecular clock estimates. Viruses , and particularly RNA viruses form clades. These are useful in tracking
92-539: A crucial role in seedling establishment. They consume many different kinds of fungi , including those involved in symbiotic mycorrhizal associations with trees, and are a vector for dispersal of the spores of subterranean sporocarps (truffles) in some regions. Chipmunks construct extensive burrows which can be more than 3.5 m (11 ft) in length with several well-concealed entrances. The sleeping quarters are kept clear of shells, and feces are stored in refuse tunnels. The eastern chipmunk hibernates in
115-811: A lithograph of the chipmunk in their Viviparous Quadrupeds of North America , calling it the "chipping squirrel [or] hackee". Chipmunks have also been referred to as "ground squirrels" (although the name "ground squirrel" may refer to other squirrels, such as those of the genus Spermophilus ). Chipmunks have an omnivorous diet primarily consisting of seeds, nuts and other fruits, and buds . They also commonly eat grass, shoots, and many other forms of plant matter, as well as fungi , insects and other arthropods , small frogs, worms, and bird eggs. They will also occasionally eat newly hatched baby birds. Around humans, chipmunks can eat cultivated grains and vegetables, and other plants from farms and gardens, so they are sometimes considered pests. Chipmunks mostly forage on
138-422: A revised taxonomy based on a concept strongly resembling clades, although the term clade itself would not be coined until 1957 by his grandson, Julian Huxley . German biologist Emil Hans Willi Hennig (1913–1976) is considered to be the founder of cladistics . He proposed a classification system that represented repeated branchings of the family tree, as opposed to the previous systems, which put organisms on
161-429: A suffix added should be e.g. "dracohortian". A clade is by definition monophyletic , meaning that it contains one ancestor which can be an organism, a population, or a species and all its descendants. The ancestor can be known or unknown; any and all members of a clade can be extant or extinct. The science that tries to reconstruct phylogenetic trees and thus discover clades is called phylogenetics or cladistics ,
184-438: Is a stub . You can help Misplaced Pages by expanding it . Clade In biological phylogenetics , a clade (from Ancient Greek κλάδος (kládos) 'branch'), also known as a monophyletic group or natural group , is a grouping of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree . In the taxonomical literature, sometimes
207-499: Is also used with a similar meaning in other fields besides biology, such as historical linguistics ; see Cladistics § In disciplines other than biology . The term "clade" was coined in 1957 by the biologist Julian Huxley to refer to the result of cladogenesis , the evolutionary splitting of a parent species into two distinct species, a concept Huxley borrowed from Bernhard Rensch . Many commonly named groups – rodents and insects , for example – are clades because, in each case,
230-476: Is in turn included in the mammal, vertebrate and animal clades. The idea of a clade did not exist in pre- Darwinian Linnaean taxonomy , which was based by necessity only on internal or external morphological similarities between organisms. Many of the better known animal groups in Linnaeus's original Systema Naturae (mostly vertebrate groups) do represent clades. The phenomenon of convergent evolution
253-515: Is responsible for many cases of misleading similarities in the morphology of groups that evolved from different lineages. With the increasing realization in the first half of the 19th century that species had changed and split through the ages, classification increasingly came to be seen as branches on the evolutionary tree of life . The publication of Darwin's theory of evolution in 1859 gave this view increasing weight. In 1876 Thomas Henry Huxley , an early advocate of evolutionary theory, proposed
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#1732791578408276-489: Is still controversial. As an example, see the full current classification of Anas platyrhynchos (the mallard duck) with 40 clades from Eukaryota down by following this Wikispecies link and clicking on "Expand". The name of a clade is conventionally a plural, where the singular refers to each member individually. A unique exception is the reptile clade Dracohors , which was made by haplology from Latin "draco" and "cohors", i.e. "the dragon cohort "; its form with
299-650: The Latin form cladus (plural cladi ) is used rather than the English form. Clades are the fundamental unit of cladistics , a modern approach to taxonomy adopted by most biological fields. The common ancestor may be an individual, a population , or a species ( extinct or extant ). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over
322-466: The chipmunks' morphological similarities. As a result, most taxonomies over the twentieth century have placed the chipmunks into a single genus. However, studies of mitochondrial DNA show that the divergence between each of the three chipmunk groups is comparable to the genetic differences between Marmota and Spermophilus , so the three genera classifications have been adopted here. The common name originally may have been spelled "chitmunk", from
345-592: The exception of the Siberian chipmunk which is found primarily in Asia . Chipmunks may be classified either as a single genus, Tamias , or as three genera: Tamias , of which the eastern chipmunk ( T. striatus ) is the only living member; Eutamias , of which the Siberian chipmunk ( E. sibiricus ) is the only living member; and Neotamias , which includes the 23 remaining, mostly western North American, species. These classifications were treated as subgenera due to
368-483: The ground, but they climb trees to obtain nuts such as hazelnuts and acorns . At the beginning of autumn, many species of chipmunk begin to stockpile nonperishable foods for winter. They mostly cache their foods in a larder in their burrows and remain in their nests until spring, unlike some other species which make multiple small caches of food. Cheek pouches allow chipmunks to carry food items to their burrows for either storage or consumption. Eastern chipmunks,
391-546: The group consists of a common ancestor with all its descendant branches. Rodents, for example, are a branch of mammals that split off after the end of the period when the clade Dinosauria stopped being the dominant terrestrial vertebrates 66 million years ago. The original population and all its descendants are a clade. The rodent clade corresponds to the order Rodentia, and insects to the class Insecta. These clades include smaller clades, such as chipmunk or ant , each of which consists of even smaller clades. The clade "rodent"
414-430: The largest of the chipmunks, mate in early spring and again in early summer, producing litters of four or five young twice each year. Western chipmunks breed only once a year. The young emerge from the burrow after about six weeks and strike out on their own within the next two weeks. These small mammals fulfill several important functions in forest ecosystems . Their activities harvesting and hoarding tree seeds play
437-590: The last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic . Some of the relationships between organisms that the molecular biology arm of cladistics has revealed include that fungi are closer relatives to animals than they are to plants, archaea are now considered different from bacteria , and multicellular organisms may have evolved from archaea. The term "clade"
460-518: The latter term coined by Ernst Mayr (1965), derived from "clade". The results of phylogenetic/cladistic analyses are tree-shaped diagrams called cladograms ; they, and all their branches, are phylogenetic hypotheses. Three methods of defining clades are featured in phylogenetic nomenclature : node-, stem-, and apomorphy-based (see Phylogenetic nomenclature§Phylogenetic definitions of clade names for detailed definitions). The relationship between clades can be described in several ways: The age of
483-504: The native Odawa (Ottawa) word jidmoonh , meaning "red squirrel" ( cf. Ojibwe ᐊᒋᑕᒨ ajidamoo ). The earliest form cited in the Oxford English Dictionary is "chipmonk", from 1842. Other early forms include "chipmuck" and "chipminck", and in the 1830s they were also referred to as "chip squirrels", probably in reference to the sound they make. In the mid-19th century, John James Audubon and his sons included
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#1732791578408506-640: The spread of viral infections . HIV , for example, has clades called subtypes, which vary in geographical prevalence. HIV subtype (clade) B, for example is predominant in Europe, the Americas and Japan, whereas subtype A is more common in east Africa. Chipmunk 3, see text Chipmunks are small, striped rodents of Sciuridae , the squirrel family; specifically, they are ground squirrels (Marmotini). Chipmunks are found in North America , with
529-570: The winter, while western chipmunks do not, relying on the stores in their burrows. Chipmunks play an important role as prey for various predatory mammals and birds but are also opportunistic predators themselves, particularly with regard to bird eggs and nestlings , as in the case of eastern chipmunks and mountain bluebirds ( Siala currucoides ). Chipmunks typically live about three years, although some have been observed living to nine years in captivity. Chipmunks are diurnal . In captivity, they are said to sleep for an average of about 15 hours
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