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39-802: The Western Malayo-Polynesian (WMP) languages , also known as the Hesperonesian languages , are a paraphyletic grouping of Austronesian languages that includes those Malayo-Polynesian languages that do not belong to the Central–Eastern Malayo-Polynesian (CEMP) branch. This includes all Austronesian languages spoken in Madagascar , Mainland Southeast Asia , the Philippines , the Greater Sunda Islands (including smaller neighboring islands), Bali , Lombok ,

78-479: A "single common ancestor" organism. Paraphyly is common in speciation , whereby a mother species (a paraspecies ) gives rise to a daughter species without itself becoming extinct. Research indicates as many as 20 percent of all animal species and between 20 and 50 percent of plant species are paraphyletic. Accounting for these facts, some taxonomists argue that paraphyly is a trait of nature that should be acknowledged at higher taxonomic levels. Cladists advocate

117-592: A cell nucleus, a plesiomorphy ) from its excluded descendants. Also, some systematists recognize paraphyletic groups as being involved in evolutionary transitions, the development of the first tetrapods from their ancestors for example. Any name given to these hypothetical ancestors to distinguish them from tetrapods—"fish", for example—necessarily picks out a paraphyletic group, because the descendant tetrapods are not included. Other systematists consider reification of paraphyletic groups to obscure inferred patterns of evolutionary history. The term " evolutionary grade "

156-423: A combination of synapomorphies and symplesiomorphies . If many subgroups are missing from the named group, it is said to be polyparaphyletic. The term received currency during the debates of the 1960s and 1970s accompanying the rise of cladistics , having been coined by zoologist Willi Hennig to apply to well-known taxa like Reptilia ( reptiles ), which is paraphyletic with respect to birds . Reptilia contains

195-401: A different species, especially in the absence of fossils documenting the gradual transition from one to another. This is in contrast to cladogenesis—or speciation in a sense—in which a population is split into two or more reproductively isolated groups and these groups accumulate sufficient differences to become distinct species. The punctuated equilibria hypothesis suggests that anagenesis

234-419: A group of dinosaurs (part of Diapsida ), both of which are "reptiles". Osteichthyes , bony fish, are paraphyletic when circumscribed to include only Actinopterygii (ray-finned fish) and Sarcopterygii (lungfish, etc.), and to exclude tetrapods ; more recently, Osteichthyes is treated as a clade, including the tetrapods. The " wasps " are paraphyletic, consisting of the narrow-waisted Apocrita without

273-470: A grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic with respect to the excluded subgroups. In contrast, a monophyletic grouping (a clade ) includes a common ancestor and all of its descendants. The terms are commonly used in phylogenetics (a subfield of biology ) and in the tree model of historical linguistics . Paraphyletic groups are identified by

312-439: A kind of lizard). Put another way, viviparity is a synapomorphy for Theria within mammals, and an autapomorphy for Eulamprus tympanum (or perhaps a synapomorphy, if other Eulamprus species are also viviparous). Groupings based on independently-developed traits such as these examples of viviparity represent examples of polyphyly , not paraphyly. The following list recapitulates a number of paraphyletic groups proposed in

351-445: A lot of", and refers to the fact that a polyphyletic group includes organisms arising from multiple ancestral sources. Groups that include all the descendants of a common ancestor are said to be monophyletic . A paraphyletic group is a monophyletic group from which one or more subsidiary clades (monophyletic groups) are excluded to form a separate group. Philosopher of science Marc Ereshefsky has argued that paraphyletic taxa are

390-560: A more inclusive clade, it often makes sense to study the paraphyletic group that remains without considering the larger clade. For example, the Neogene evolution of the Artiodactyla (even-toed ungulates, like deer, cows, pigs and hippopotamuses - Cervidae , Bovidae , Suidae and Hippopotamidae , the families that contain these various artiodactyls, are all monophyletic groups) has taken place in environments so different from that of

429-471: A paraphyletic grouping, because they exclude the eukaryotes , a descendant group. Bacteria and Archaea are prokaryotes, but archaea and eukaryotes share a common ancestor that is not ancestral to the bacteria. The prokaryote/eukaryote distinction was proposed by Edouard Chatton in 1937 and was generally accepted after being adopted by Roger Stanier and C.B. van Niel in 1962. The botanical code (the ICBN, now

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468-424: A phylogenetic species concept that does not consider species to exhibit the properties of monophyly or paraphyly, concepts under that perspective which apply only to groups of species. They consider Zander's extension of the "paraphyletic species" argument to higher taxa to represent a category error When the appearance of significant traits has led a subclade on an evolutionary path very divergent from that of

507-505: A single archaic species that lived in Afro-Eurasia. Milford H. Wolpoff is a paleoanthropologist whose work, studying human fossil records, explored anagenesis as a hypothesis for hominin evolution. When looking at anagenesis in hominids, M. H. Wolpoff describes in terms of the 'single-species hypothesis,' which is characterized by thinking of the impact that culture has on a species, as an adaptive system, and as an explanation for

546-436: A species can be acknowledged as being different from the previous. An alternative definition offered for anagenesis involves progeny relationships between designated taxa with one or more denominated taxa in line with a branch from the evolutionary tree. Taxa must be within the species or genus and will help identify possible ancestors. When looking at evolutionary descent, there are two mechanisms at play. The first process

585-499: A unique common ancestor. Conversely, the term monophyly , or monophyletic , builds on the Ancient Greek prefix μόνος ( mónos ), meaning "alone, only, unique", and refers to the fact that a monophyletic group includes organisms consisting of all the descendants of a unique common ancestor. By comparison, the term polyphyly , or polyphyletic , uses the Ancient Greek prefix πολύς ( polús ), meaning "many,

624-433: Is allowed as a synonym of Magnoliopsida. Phylogenetic analysis indicates that the monocots are a development from a dicot ancestor. Excluding monocots from the dicots makes the latter a paraphyletic group. Among animals, several familiar groups are not, in fact, clades. The order Artiodactyla ( even-toed ungulates ) as traditionally defined is paraphyletic because it excludes Cetaceans (whales, dolphins, etc.). Under

663-437: Is not paraphyletic or monophyletic can be called polyphyletic. Empirically, the distinction between polyphyletic groups and paraphyletic groups is rather arbitrary, since the character states of common ancestors are inferences, not observations. These terms were developed during the debates of the 1960s and 1970s accompanying the rise of cladistics . Paraphyletic groupings are considered problematic by many taxonomists, as it

702-433: Is not possible to talk precisely about their phylogenetic relationships, their characteristic traits and literal extinction. Related terms are stem group , chronospecies , budding cladogenesis, anagenesis, or 'grade' groupings. Paraphyletic groups are often relics from outdated hypotheses of phylogenic relationships from before the rise of cladistics. The prokaryotes (single-celled life forms without cell nuclei) are

741-401: Is rare and that the rate of evolution is most rapid immediately after a split which will lead to cladogenesis, but does not completely rule out anagenesis. Distinguishing between anagenesis and cladogenesis is particularly relevant in the fossil record, where limited fossil preservation in time and space makes it difficult to distinguish between anagenesis, cladogenesis where one species replaces

780-682: Is significantly differentiated from an ancestral population, a new species name may be assigned. A series of such species is collectively known as an evolutionary lineage. The various species along an evolutionary lineage are chronospecies . If the ancestral population of a chronospecies does not go extinct, then this is cladogenesis , and the ancestral population represents a paraphyletic species or paraspecies , being an evolutionary grade . The modern human origins debate caused researchers to look further for answers. Researchers were curious to know if present day humans originated from Africa, or if they somehow, through anagenesis, were able to evolve from

819-482: Is sometimes used for paraphyletic groups. Moreover, the concepts of monophyly , paraphyly, and polyphyly have been used in deducing key genes for barcoding of diverse group of species. Current phylogenetic hypotheses of tetrapod relationships imply that viviparity , the production of offspring without the external laying of a fertilized egg, developed independently in the lineages that led to humans ( Homo sapiens ) and southern water skinks ( Eulampus tympanum ,

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858-448: Is when genetic information changes. This means that over time there is enough of a difference in their genomes , and in the way that species' genes interact with each other during the developmental stage, that anagenesis can thereby be viewed as the processes of sexual and natural selection, and genetic drift's effect on an evolving species over time. The second process, speciation, is closely associated with cladogenesis. Speciation includes

897-514: The Cetacea (whales, dolphins, and porpoises) that the Artiodactyla are often studied in isolation even though the cetaceans are a descendant group. The prokaryote group is another example; it is paraphyletic because it is composed of two Domains (Eubacteria and Archaea) and excludes (the eukaryotes ). It is very useful because it has a clearly defined and significant distinction (absence of

936-581: The ICN ) abandoned consideration of bacterial nomenclature in 1975; currently, prokaryotic nomenclature is regulated under the ICNB with a starting date of 1 January 1980 (in contrast to a 1753 start date under the ICBN/ICN). Among plants, dicotyledons (in the traditional sense) are paraphyletic because the group excludes monocotyledons . "Dicotyledon" has not been used as a botanic classification for decades, but

975-479: The Plio-Pleistocene range. Once more research was done, specifically with the fossils of A. anamensis and A. afarensis , researchers were able to justify that these two hominin species were linked ancestrally. However, looking at data collected by William H. Kimbel and other researchers, they viewed the history of early hominin fossils and concluded that actual macroevolution change via anagenesis

1014-660: The ants and bees . The sawflies ( Symphyta ) are similarly paraphyletic, forming all of the Hymenoptera except for the Apocrita, a clade deep within the sawfly tree. Crustaceans are not a clade because the Hexapoda (insects) are excluded. The modern clade that spans all of them is the Tetraconata . One of the goals of modern taxonomy over the past fifty years has been to eliminate paraphyletic "groups", such as

1053-479: The DEM, whereas cladogenesis is viewed by observing the separation and movement of the dots across the map. Controversy arises among taxonomists as to when the differences are significant enough to warrant a new species classification: Anagenesis may also be referred to as gradual evolution. The distinction of speciation and lineage evolution as anagenesis or cladogenesis can be controversial, and some academics question

1092-435: The actual separation of lineages, into two or more new species, from one specified species of origin. Cladogenesis can be seen as a similar hypothesis to anagenesis, with the addition of speciation to its mechanisms. Diversity on a species-level is able to be achieved through anagenesis. Anagenesis suggests that evolutionary changes can occur in a species over time to a sufficient degree that later organisms may be considered

1131-403: The conditions humans tend to live in, based on the environmental conditions, or the ecological niche. When judging the effect that culture has as an Adaptive System, scientists must first look at modern Homo Sapiens. Wolpoff contended that the ecological niche of past, extinct hominidae is distinct within the line of origin. Examining early Pliocene and late Miocenes findings helps to determine

1170-429: The corresponding importance of Anagenesis vs. Cladogenesis during the period of morphological differences. These findings propose that branches of the human and chimpanzee once diverged from each other. The hominin fossils go as far as 5 to 7 million years ago (Mya). Diversity on a species-level is able to be achieved through anagenesis. With collected data, only one or two early hominin were found to be relatively close to

1209-450: The examples given here, from formal classifications. Species have a special status in systematics as being an observable feature of nature itself and as the basic unit of classification. Some articulations of the phylogenetic species concept require species to be monophyletic, but paraphyletic species are common in nature, to the extent that they do not have a single common ancestor. Indeed, for sexually reproducing taxa, no species has

Western Malayo-Polynesian languages - Misplaced Pages Continue

1248-428: The island of Taiwan . Anagenesis One hypothesis is that during the speciation event in anagenetic evolution, the original populations will increase quickly, and then rack up genetic variation over long periods of time by mutation and recombination in a stable environment. Other factors such as selection or genetic drift will have such a significant effect on genetic material and physical traits that

1287-528: The last common ancestor of reptiles and all descendants of that ancestor except for birds. Other commonly recognized paraphyletic groups include fish , monkeys , and lizards . The term paraphyly , or paraphyletic , derives from the two Ancient Greek words παρά ( pará ), meaning "beside, near", and φῦλον ( phûlon ), meaning "genus, species", and refers to the situation in which one or several monophyletic subgroups of organisms (e.g., genera, species) are left apart from all other descendants of

1326-622: The literature, and provides the corresponding monophyletic taxa. The concept of paraphyly has also been applied to historical linguistics , where the methods of cladistics have found some utility in comparing languages. For instance, the Formosan languages form a paraphyletic group of the Austronesian languages because they consist of the nine branches of the Austronesian family that are not Malayo-Polynesian and are restricted to

1365-422: The other, or simple migration patterns. Recent evolutionary studies are looking at anagenesis and cladogenesis for possible answers in developing the hominin phylogenetic tree to understand morphological diversity and the origins of Australopithecus anamensis , and this case could possibly show anagenesis in the fossil record. When enough mutations have occurred and become stable in a population so that it

1404-696: The ranks of the ICZN Code , the two taxa are separate orders. Molecular studies, however, have shown that the Cetacea descend from artiodactyl ancestors, although the precise phylogeny within the order remains uncertain. Without the Cetaceans the Artiodactyls are paraphyletic. The class Reptilia is paraphyletic because it excludes birds (class Aves ). Under a traditional classification, these two taxa are separate classes. However birds are sister taxon to

1443-445: The result of anagenesis in the excluded group or groups. A cladistic approach normally does not grant paraphyletic assemblages the status of "groups", nor does it reify them with explanations, as in cladistics they are not seen as the actual products of evolutionary events. A group whose identifying features evolved convergently in two or more lineages is polyphyletic (Greek πολύς [ polys ], "many"). More broadly, any taxon that

1482-640: The western half of Sumbawa , Palau and the Mariana Islands . Western Malayo-Polynesian was originally proposed by Robert Blust as a sister branch within Malayo-Polynesian coordinate to the CEMP branch. Because there are no features that define the WMP languages positively as a subgroup, recent classifications have abandoned it. Paraphyletic Paraphyly is a taxonomic term describing

1521-418: Was scarce. DEM (or Dynamic Evolutionary Map) is a different way to track ancestors and relationships between organisms. The pattern of branching in phylogenetic trees and how far the branch grows after a species lineage has split and evolved, correlates with anagenesis and cladogenesis. However, in DEM dots depict the movement of these different species. Anagenesis is viewed by observing the dot movement across

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