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Topic: Polyphyletic

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  Polyphyletic - Wikipedia, the free encyclopedia
In phylogenetics, a taxon is polyphyletic if it is descended from more than one root form (in Greek poly = many and phyletic = racial).
The "lower land vertebrates" are a polyphyletic group.
Scientific classification aims to group species together such that every group is descended from a single common ancestor, and the elimination of groups that are found to be polyphyletic is therefore a common goal, and is often the stimulus for major revisions of the classification schemes.
www.hackettstown.us /project/wikipedia/index.php/Polyphyletic   (230 words)

 Polyphyly - Wikipedia, the free encyclopedia
In phylogenetics, a taxon is polyphyletic (Greek for "of many races") if the trait its members have in common evolved separately in different places in the phylogenetic tree.
Equivalently, a polyphyletic taxon does not contain the most recent common ancestor of all its members.
For example, the group of warm-blooded animals is polyphyletic, because it contains both mammals and birds, but the most recent common ancestor of mammals and birds was cold-blooded.
en.wikipedia.org /wiki/Polyphyletic   (265 words)

Polyphyletic hypotheses, such as those of Fryer, propose multiple origins of the major subphyla.
The monophyly vs polyphyly debate began with Haeckel's hypothesis of monophyly in the mid-1800s.
Manton's belief that different basal arthropod types could not have given rise to each other (therefore the group must be polyphyletic) was countered with the argument that they all could have had a similar origin.
www.biology.ualberta.ca /courses.hp/biol606/OldLecs/Lecture.98.01.Zaklan.html   (968 words)

 Cladistics - Wikipedia, the free encyclopedia
For instance, the once-recognized Pachydermata was found to be polyphyletic because elephants and rhinoceroses arose from non-pachyderms separately.
Evolutionary taxonomists consider polyphyletic groups to be errors in classification, often occurring because convergence or other homoplasy was misinterpreted as homology.
In contrast, paraphyletic and polyphyletic groups are both defined based on key characters, and the decision of which characters are of taxonomic import is inherently subjective.
en.wikipedia.org /wiki/Cladistics   (1683 words)

 Human Biology: Relationships by isonymy between persons with monophyletic and polyphyletic surnames from the Monterrey ...   (Site not responding. Last check: 2007-11-06)
When a patient reported that one of his or her close relatives had already been interviewed, the data for that person were laid aside, as were data for a member of the same family attending on the same date.
The number of complementary surnames of the selected persons with monophyletic and polyphyletic (patronymic or matronymic) names, the distribution of their maternal and paternal complementary surnames, and the percentages of unique, different, and most common complementary surnames are given in Table 1.
The coefficients of isonymy within the selected persons with monophyletic and polyphyletic (patronymic and matronymic) surnames (R sub iw x 10 sup 3) based on the occurrences of the maternal and paternal complementary surnames are given in Table 3.
www.findarticles.com /p/articles/mi_qa3659/is_199412/ai_n8731442   (1224 words)

 Evolution: Chloroplast Genetics and Endosymbiosis
The concensus is that plastids in green plants and green algae are monophyletic.
The rhodophytes (red algae) seem to have had an early divergence before the plant, fungus, and animal lineage, and therefore rhodoplasts may be polyphyletic to the green plastids.
Plastids in the red algae appear to be of polyphyletic origin relative to the green plastid lineage.
www.geocities.com /we_evolve/Plants/chloroplast.html   (3184 words)

 Cladistics   (Site not responding. Last check: 2007-11-06)
For example, the once-recognized group Pachydermata was found to be polyphyletic because an elephant and a rhinoceros were each found to be more closely related to non-pachyderms than either to each other.
Biologists consider groups that turn out to be polyphyletic to be errors in classification, often occurring because convergence or other homoplasy was misinterpreted as homology.
If a named group is found to include some but not all of the descendants of the ancestor on which the group is based, it is termed paraphyletic.
www.sciencedaily.com /encyclopedia/cladistics   (1330 words)

 Evolution - A-Z - Paraphyletic group   (Site not responding. Last check: 2007-11-06)
Polyphyletic groups are formed when two lineages convergently evolve similar character states.
Polyphyletic groups are recognized by pheneticists but not by cladists or evolutionary classifiers.
Reptiles are a paraphyletic group: in terms of appearance a crocodile has more in common with lizards than birds and both crocodiles and lizards are classed as reptiles.
www.blackwellpublishing.com /ridley/a-z/Paraphyletic_group.asp   (185 words)

 Blackwell Synergy - Heredity, Vol 81, Issue 1, pp. 38-47: Allozyme variability in sexual and parthenogenetic freshwater ...
The observed genotypic diversity suggests that parthenogens from mixed populations are of polyphyletic origin.
Polyphyletic origins of parthenogens have been supported previously by the existence and distribution of cytogenetically different parthenogenetic biotypes (Benazzi, 1957; Beukeboom et al., 1996).
Diverse, endemic and polyphyletic clones in mixed populations of a freshwater snail (Potamopyrgus antipodarum).
www.ice.mpg.de /clib/fulltext/pube/mio/MIO107.htm   (3539 words)

 Phylogeny of the Kinetoplastida: Taxonomic Problems and Insights into the Evolution of Parasitism
In trypanosomatids, the genera Leptomonas and Blastocrithidia were polyphyletic, similar to the genera Herpetomonas and Crithidia and in contrast to the monophyletic genera Trypanosoma and Phytomonas.
The genera Herpetomonas and Crithidia were polyphyletic: the endosymbiont-containing members of these genera formed a separate monophyletic clade, while the endosymbiont-free members were found elsewhere on the tree.
With at least four genera of trypanosomatids being polyphyletic (Crithidia, Herpetomonas, Leptomonas and Blastocrithidia), it has become obvious that the morphological taxonomy of trypa-nosomatids does not reflect their genetic affinities and should be revised in the future.
memorias.ioc.fiocruz.br /963/4213hm.html   (1974 words)

 Protoctista   (Site not responding. Last check: 2007-11-06)
This one is not perfect in that regard as the Protoctista and the Monera are undoubtedly polyphyletic (ie include groups that are not closely related to each other).
The group is almost certainly polyphyletic and does not reflect evolutionary relationships.
(Polyphyletic means that the group does not have a single common ancestor in the group.
www.lander.edu /rsfox/112protc.html   (3762 words)

 MORT, MARK E.*, DOUGLAS E. SOLTIS, AND PAMELA S. SOLTIS.   (Site not responding. Last check: 2007-11-06)
For example, Sedum, the largest genus of Crassulaceae, has been referred to as a "dust bin taxon", suggesting it is polyphyletic.
Our analyses reveal six major clades and suggest that five of the six subfamilies currently recognized are polyphyletic.
In addition, our data indicate that Sedum, the largest genus in the family, is a grossly polyphyletic assemblage of taxa, confirming the results of cytology and recent molecular analyses.
www.ou.edu /cas/botany-micro/bsa-abst/section13/abstracts/68.shtml   (285 words)

 Lecture Nov 20   (Site not responding. Last check: 2007-11-06)
Monophyletic groups (clades in the words of tree-thinkers) are worthy of taxonomic recognition (at whatever level: genus, family, order.
Polyphyletic or paraphyletic groups cannot be designated as discrete taxa (a taxon is a taxonomic unit of unspecified level -- species, genus, whatever).
Some quick definitions needed here; polyphyletic = derived from more than one ancestral group (or, you can't shake one branch of the tree and have only your group move); paraphyletic = you have a monophlyletic clade OK, but within your clade not all members are of the same taxon.
www.lclark.edu /~seavey/bio210/lecture_Nov_20.html   (590 words)

 Milford H. Wolpoff and Rachel Caspari: Response to Grappling with the Ghost of Gould by David P. Barash   (Site not responding. Last check: 2007-11-06)
His book review essay, quite appropriately named, ends with the exaltation to “consider, as a final extended quotation, this marvelous rhetorical flourish against the polyphyletic theory of human origins.” This is followed by a citation of Gould’s terminal mischaracterization of multiregional evolution as a polygenic theory based on parallel evolution.
Gould consistently misportrayed it and widely publicized multiregional evolution as a polyphyletic model of parallel racial evolution similar to that of Carlton Coon’s in the 1960s.
In any other discipline it would be laughable to have to deal with a theory dead for more than a half century, as if current physics papers needed to repeatedly prove that distant galaxies were red shifted, or continued to debate whether light was a particle or a wave.
human-nature.com /nibbs/02/wolpoff.html   (378 words)

 Palaeos Invertebrates: Mollusca: Tryblidiida: Problems with defining the "Monoplacophora"   (Site not responding. Last check: 2007-11-06)
Trying to establish a systemmatic classification of the "Monoplacophora" is not easy, especially since it seems that "Monoplacophora" is a polyphyletic grade rather than a natural group.
As with all molluscs, and understanding of the soft parts are important, and, apart from the living Neopilina, representing only a single order and family of this once diverse group, and muscle scars on fossil shells, these are lacking.
It is quite likely that the "Monoplacophora" is a polyphyletic grouping, as cladistic analysis gives confusing results.
www.palaeos.com /Invertebrates/Molluscs/Tryblidiida/Monoplacophora.html   (308 words)

 Comparative Anatomy Topic 2 - Phylogenies and Fossils   (Site not responding. Last check: 2007-11-06)
Polyphyletic group - a group consisting of two or more distantly related species (an extreme of paraphyly); in cladistics, this is an invalid grouping because it does not express evolutionary relationships
A + B could be considered either paraphyletic or polyphyletic although I personally would have went with paraphyletic.
What is the smallest monophyletic group consisting of taxa J and K? Turtles, tuataras, lizards, snakes, crocodiles, dinosaurs, birds, and mammals are all in Amniota.
www.auburn.edu /academic/classes/zy/0301/Topic2/topic2.html   (754 words)

 Puffball article - Puffball fungi polyphyletic Basidiomycota spores cloud brown spores secotioid - What-Means.com   (Site not responding. Last check: 2007-11-06)
Puffball article - Puffball fungi polyphyletic Basidiomycota spores cloud brown spores secotioid - What-Means.com
Puffballs are fungi, they consist of a polyphyletic assemblage of Basidiomycota with gasterothecia (gasteroid basidiocarps) in which the spores are produced internally; that is, the basidiocarp remains closed, or opens only after the spores have been released from the basidia.
Their spores are statismospores rather than ballistospores, meaning they are not actively shot off the basidium.
www.what-means.com /encyclopedia/Puffballs   (471 words)

 Polyphyletic   (Site not responding. Last check: 2007-11-06)
polyphyletic si se desciende de más de un formulario de la raíz.
La clasificación científica apunta agrupar la especie junta tales que descienden a cada grupo de un solo antepasado común, y la eliminación de los grupos que se encuentran para ser polyphyletic es por lo tanto una meta común, y es a menudo el estímulo para las revisiones importantes de los esquemas de la clasificación.
Sin embargo, muchos otros taxonomists discutirían que haya un lugar válido para los grupos que son paraphyletic, es decir contenga solamente a descendientes de un antepasado común, pero no contenga a todos sus descendientes.
www.yotor.net /wiki/es/po/Polyphyletic.htm   (173 words)

 The Virtual Museum.
Animals with many features in common may prove not to be as closely related as their classification would suggest.
For example, if all fishes were grouped into a class Pisces (as they once were), this would be polyphyletic, for it would include sharks and other cartilaginous fishes.
The bony fishes themselves have long been grouped into the class Osteichthyes, but even this is polyphyletic: it includes two distinct groups, the actinopterygians (ray-finned fishes) and sarcopterygians (lungfishes, coelacanths and extinct lobe-finned fishes), which are sufficiently distinct to be considered classes.
www.abdn.ac.uk /zoologymuseum/professor/polyphy2.html   (119 words)

 RA   (Site not responding. Last check: 2007-11-06)
They were selected by their monophylet ic or polyphyletic surnames.
It was found that for persons with monophyletic and polyphyletic surnames, as well as for the other populations in the MMA and ot her places in Mexico, their ABO and Rho(D) MI and MFI percent of risk are intermediate to the ones estimated for their ancestry.
The percentages of MI and MFI are higher for the persons with monophyletic than for the ones with polyphyletic surnames, other populations from the MMA and those from other locations in Mexico.
www.unam.mx /serv_hem/revistas/medical/1996/summer/a23.html   (210 words)

 What do terms like monophyletic, paraphyletic and polyphyletic mean?
These terms are used to describe groupings of organisms, and indicate the extent to which they can be considered as ``natural groups''.
This is a polyphyletic group - a totally unnatural assemblage - because it can't even be expressed as a paraphyletic group, that is, a clade minus one or more of its subclades.
Such groups are not used at all in phylogenetic work since they are a purely artificial construct.
www.miketaylor.org.uk /dino/faq/s-class/phyletic   (814 words)

 Polyphyletic Encyclopedia Article, Definition, History, Biography   (Site not responding. Last check: 2007-11-06)
Looking For polyphyletic - Find polyphyletic and more at Lycos Search.
Find polyphyletic - Your relevant result is a click away!
Look for polyphyletic - Find polyphyletic at one of the best sites the Internet has to offer!
www.karr.net /encyclopedia/Polyphyletic   (404 words)

 Zoology 404, Chapter 14 notes   (Site not responding. Last check: 2007-11-06)
Operationally, a paraphyletic group is defined by a suite of ancestral traits which have been modified or lost in the excluded species.
A polyphyletic group consists of species whose common ancestor is not included within the group.
Operationally, a polyphyletic group is defined by convergent traits (analogies).
www.science.siu.edu /zoology/king/404/mr14.htm   (1483 words)

 Learn more about Polyphyletic in the online encyclopedia.   (Site not responding. Last check: 2007-11-06)
Learn more about Polyphyletic in the online encyclopedia.
Hint: Play with putting spaces before and after your words to see the different results you get.
Scientific classification aims to group species together such that every group is monophyletic: i.e.
www.onlineencyclopedia.org /p/po/polyphyletic.html   (120 words)

 POLYPHYLETIC   (Site not responding. Last check: 2007-11-06)
Pertaining to, or characterized by, descent from more than one root form, or from many different root forms; polygenetic; -- opposed to monophyletic.
Date "POLYPHYLETIC" was first used in popular English literature: sometime before 1991.
Source: compiled by the editor, based on several corpora (additional references).
www.websters-online-dictionary.org /Po/Polyphyletic.html   (259 words)

 Lec 6 Origin of Dinosauria
(The Thecondontia are a heterogeneous nondinosaurian paraphyletic and polyphyletic group of basal archosaurs.) Seeley referred to the dinosaurs as a diphyletic group, that is, each group had a distinct and separate ancestry from within the thecodonts.
The belief that dinosaurs were polyphyletic continued into this century.
Many dinosaur paleontologists believed that dinosaurs were polyphyletic up until the 1960s and 70s.
www.wvup.edu /ecrisp/lecoriginofdinosauria.html   (1454 words)

 Freshwater Molluscan Shells   (Site not responding. Last check: 2007-11-06)
The material presented here is organized in a manner typical of Abbott -- zoologically down to the family level, then (where I have sufficient material) regionally.
Freshwater mollusks, being thoroughly polyphyletic, cannot be classified independently of the rest of the great invertebrate phylum mollusca.
Below is an evolutionary tree diagram for the mollusca modified from Brusca and Brusca (1990), p 762.
members.aol.com /mkohl1/FWshells.html   (2264 words)

 Tree of Life Glossary
Any of a polyphyletic grouping of organisms which move and feed using pseudopodia.
A group of organisms that includes their most recent common ancestor and some but not all of its descendents.
An interaction between organisms in which one organism (the parasite) lives in or on the living tissue of another organism (the host), deriving nutrients at the expense of the host.
tolweb.org /tree/home.pages/glossary.html   (5247 words)

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