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That's wrong. If H. heidelbergensis and H. neanderthalensis were subspecies of H.sapiens, then they would by definition HAVE common ancestral form, and that wouldn't interfere with monophylecity of Homo in any way. -- Taw
One way or the other, folks, Homo is not a good example. More enlightening quibbles are found in the Dinosauria/Aves cladistics, no?
This entry must mention cladistics/clades to be intelligible. User:Wetman
Portions of this are unintelligible or simply wrong. I'm not sure I'm up to completely rewriting it at the moment, but I will mention the basic problems here in case there is a strong defense of the status quo:
1) Holophyly vs. monophyly. Discussion of holophyly in this article is probable best limited to the current statement "The term is synonymous with the uncommon term holophyly." Yes, there was a brief interest in using the word "holophyly" for what we presently call "monophyly", but this is a minor side issue, while this article seems to suggest that it is the main event. If discussion of this rather defunct debate is necessary, it would best be placed in the article for the term "holophyly", since that term is wholly a creature of that debate, while "monophyly" is not.
2) There are a number of sentences in the article at present, such as "However, when considering taxonomic groups such as genera and species, the most appropriate nature of this common ancestor is unclear. Assuming that this is one individual or mating pair is unrealistic for species, which are by definition interbreeding populations.[1]" and "Naming is also a problem for monophyletic groups: because the number of ancestors from which to root monophyletic groups is almost infinite, giving each clade a unique name is impossible[4] - as illustrated by the failed attempts to instigate a system called the Phylocode. Names obfuscate the really interesting part, which is the branching order, and are therefore of little utility to the cladist [...]" that highlight eccentric objections to cladism. Through their inclusion, they give the impression that the concept of monophyly is shrouded in obscurity and controversy, and are obfuscatory rather than explanatory. An NPOV article should, presumably, attempt to highlight and clarify the mainstream usage and definition of the term. Discussions of disagreement with this mainstream view should not necessarily be removed entirely, but they should not dominate it.
3) Whether a taxon *includes* the common ancestor of the extant members is a somewhat thorny issue that should at least be mentioned in a coherent fashion. At present, the article advocates the inclusion of extinct species within a cladistic classification of extant species without discussion, but also disagrees with itself occasionally; this is not helpful.
4) There seems to be confusion between typological and phylogenetic classifications, e.g.: "For instance, Archaeopteryx appears more reptilian than bird - it has teeth and a number of other reptilian characteristics. But it also has feathers, which have traditionally been considered as an avian trait. It lacks a number of other traits shared by all birds, so can't fall within the bird clade." If Aves is defined phylogenetically, its membership is determined based on the common ancestry of its members and nothing more. Only if Aves is defined typologically are specific traits considered to be necessary and/or sufficient conditions for membership. But in this example, Archaeopteryx is claimed to be excluded from a *clade* (a phylogenetic unit) on the basis of absence of certain characters that are supposedly requisite for membership; i.e., a typological interpretation of taxon membership is applied to a clade. This example is further confused by the problems encountered by attempting to include extinct taxa consistently in a classification of extant taxa, as mentioned above.
5) And a very minor point; calling a clade "a monophyly" is a very unusual construction. I do not think I have ever seen it used in the phylogenetic literature; likely it is out there somewhere, but it is at least anomalous. Paalexan ( talk) 00:19, 15 November 2009 (UTC)
The definition of polypheltic, as distinct from paraphyletic, doesn't make sense to me. Could someone help clear up the following points and/or update the article.
How is possible for the organisms in the group to not have a common ancestral form? If the evolutionary tree really is a tree then this will always be the case, and removing this condition would make no difference to the definition.
Every subset of the set of extant species will always have a latest common ancestor, so what does it mean for a taxonomic group to contain organisms but not their common ancestor?
The difference is whether the last common ancestor is in the group. For instance warm-blooded vertebrates all evolved from the ancestral reptile, but it wasn't itself warm-blooded, so they form a polyphyletic group.
Can anyone translate this into English that a lay person can understand?
I've change the sentence; hopefully the new version makes more sense. Josh
Still incomprehensible. The whole idea of an introduction is so that any reader can understand what the subject is all about. This has not been done. Way too much geekese and insider terminology. - 22:02, 22 February 2010 (UTC) —Preceding unsigned comment added by KitchM ( talk • contribs)
What is it and what is the source of the claim about multiple arisal? This article is the only one in the entire Wikipedia, as well as the internet (according to google), to ever mention such species. mathrick 00:14, 26 November 2006 (UTC)
Since Google corrects the spelling to "Tragopogon miscellus" and gives results about polyploidy and plants in Washington, I posit that "Iragopogen" is a typo. Rehevkor5 23:11, 5 December 2006 (UTC)
Is a monophyletic group basically the same as a clade?23:59, 21 December 2006 (UTC)
I'm interested in getting some comprehensible cladistics articles so I'm going to do an edit. I'm also working on a few others. it's the fine points I'm worried about, the things that make good articles good, etc. What do they got that we ain't got? Fine points. I'll be interested in clarity first. It starts well I do believe. After that the style gets less encyclopedic; maybe it tries to be Stephen Jay Gould - but - out of context. The references - well, I'm pleased to see some. That first reference, can't we have a page number?
So, don't get upset, get helpful. I work very slowly, plenty of time. Dave ( talk) 03:54, 23 January 2010 (UTC)
The early work in cladistics was done in German, and it was translated into English. Sometimes, though, the word that seems the best translation is not used or is not used that way in English, especially if the translator has opted more for transliteration. The words look the same but they aren't the same. For example, we don't speak of the characters of a bird or a reptile - a character is a symbol on a page or a condition of ethical or moral rightness. We call a feature a characteristic. But, in translational contexts, once you understand the author's use of it, character is acceptable. For the clearest English, I want to avoid translational terms and use the regular equivalent. Dave ( talk) 09:08, 24 January 2010 (UTC)
There are such problems with the English of these passages as to render them incomprehensible. First we talk about "appropriate nature." Then we refer to it with an "it" calling it also an individual or a mating pair. I'm sorry, but individuals are not a nature do not have a nature (what is the nature of Tom, Dick or Harry, and are they a nature?) and neither do mating pairs. Only universals have natures: man, bird, mammal, and so on. There is the question of the nature and the question of the common ancestor. They are not identical; you can't mix the two. I presume by nature you mean a synapomorphy. Since when is a synapomorphy? You mean, we can ignore the synapomorphies that are NOT the most appropriate nature? And what happened to the plesiomorphy, or is that what you mean by nature?
In the next paragraph, what do you mean, "doesn't really work?" First the style level is inappropriate. Second, if you mean there is a logical inconsistency, you in no way have stated what that is or even hinted what that may be. I see you are telling us that a "cladistic definition" of a species or genus is "in fact impossible." I seems as though you are trying to say that species and genera cannot be in the stem of a clade. Well, if they can't be, I'd like to know just what can be, as there can't be any more general taxa without the subordinate taxa. But, you might not mean that. Just what you do mean is completely impenetrable.
A third problem is your references. You keep citing Simpson without any page numbers. In other words, we have to search the whole book to try to find out what you mean. This superficial non-reference may satisfy the cursory inspection of a sysadmin in a hurry but it is in no way a reference. In another reference you give us a link to the abstract of an article but that abstract has not a thing to do with the above passages. Maybe the article does, but we can't get that without paying for it. You may not link to pay sites, did you not know that? Whether the article is appropriate I do not know, as I cannot understand what is being referenced. First give us an idea, then give us the reference. No idea, useless reference.
For the moment I'm leaving this passage in to give you a chance to totally rewrite it. This approach has worked well on another article. Then I will look at the rewrite. If you don't respond I will do some additional Internet work to try to find out what problems you are referencing and rewrite it myself. In my experience, I think you would be happiest doing your own work on it, so go right ahead. For the moment I will tackle the next incomprehensible cladistics article. There is no hard and fast rule, cladistics must be incomprehensible to the genral public. Good luck. Dave ( talk) 12:47, 24 January 2010 (UTC)
I have re-written the lead paragraphs to make them both clearer and more accurate. Comments welcome! Peter coxhead ( talk) 10:34, 5 December 2010 (UTC)
There are currently separate articles on monophyly, paraphyly and polyphyly. Inevitably they repeat much of the same material. Worse, they are not wholly consistent with one another (I have been trying to correct this). If there are to be three separate articles, then there is material which is missing from some of them, e.g. each should have a discussion of its advantages or disadvantages in classification. The reality is that you can only understand at least two of these terms (paraphyly and polyphyly) by contrasting them with the others. I am strongly in favour of creating one main article under one of the headings and then having short definitional articles under the other two, which use "see" to point to the main information. I would be willing to try to do this, but not if there is significant opposition. Comments please. Peter coxhead ( talk) 15:54, 6 December 2010 (UTC)
This is one of many WP articles which apparently thinks it is wrong to give a simple example of what is meant. Why not simply put in an example of some animal considered to be monophylatic (and say why) and one which is polyphylatic (and say why)? If a picture is worth a thousand words, then so is an example. To write an article on this subject without ONCE mentioning real instances of what they refer to is silly and pretentious. Myles325a ( talk) 05:48, 23 August 2011 (UTC)
For some time the definition in the lead has been "a monophyletic group is a taxon (group of organisms) which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group." This has recently been altered to "... meaning that it consists of a species and all its descendants."
The minor problem with the new version is the word "species"; this is generally not insisted on by those who use this form of definition. The ancestor could just be a population.
The major problem is explained by Mishler (2009): "There have been two basically different ways of defining monophyly within the Hennigian tradition of phylogenetic systematics: one is synchronic (i.e., “all and only descendants of a common ancestor”); another is diachronic (i.e., “an ancestor and all of its descendants”)." Mishler goes on to prefer the synchronic definition. [See Mishler, B.D. (2009), "Species are not Uniquely Real Biological Entities", in Ayala, F.J.; Arp, R. (eds.), Contemporary Debates in Philosophy of Biology, Oxford, UK: Wiley-Blackwell,
doi:
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help). There's a more detailed explanation and a suggestion – not taken up alas – for the use of different terminology for the two definitions in Podani, J. (2010),
"Taxonomy in Evolutionary Perspective : An essay on the relationships between taxonomy and evolutionary theory" (PDF), Synbiologia Hungarica, 6: 1–42.]
So I'm not going to revert the change, but actually the original is just as correct as the new version. Sorting this out has been on my to-do list for some time. Peter coxhead ( talk) 11:01, 17 April 2012 (UTC)
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help) Though Brochu does consider them different clades, there were not, to his knowledge, any sauropsids contained in either that were not contained in the other. He could not have said a priori that they were not coextensive nor, I suggest, can you confidently predict "that stem-based, node-based and apomorphy-based definitions [will always] correspond to different sets of organisms/fossils/species/whatever."
Peter M. Brown (
talk)
23:26, 18 April 2012 (UTC)This stuff is difficult to explain clearly without example diagrams to refer to (and I accept that some of my verbal explanations, including my use of "branching order", aren't very good). Since I don't want to upload to Commons diagrams which will only be of transient interest, please see here for my attempt to explain more clearly the nature of what Podani (2010) calls "phylogenetic trees" and "cladograms" and how clades can be defined in them.
The difference between "phylogenetic trees" and "cladograms" (or whatever names you call them) is not, in my view, properly explained at present in our set of articles about phylogenetics. Peter coxhead ( talk) 10:56, 19 April 2012 (UTC)
I have deleted from the end of the Monophyly#Definitions section a paragraph reading:
This fails in several ways to meet Wikipedia standards.
All the same, I do not want to delete all reference to a bona fide research tradition. Is there one? Peter Brown ( talk) 23:34, 17 July 2013 (UTC)
The distinction between monophyly sensu cladists and monophyly sensu evolutionists should be clearly and neutrally discussed. Arguments from both sides should be mentioned at least once each. Moreover, the difference between "monophyly" based on set theory (only including terminals) and "monophyly" based on graph theory (including ancestors) should be explained somewhere (see for example Podani 2009; Vanderlaan et al. 2013; Aubert 2015). BernZ ( talk) 09:53, 11 December 2015 (UTC)
the word Reptilia's modern definition in zoology books includes bird (see the wikipedia article on Reptiles, definition section), making it a monophyletic group. this definition is not 100% agreed upon as can be seen by that page's talk page. therefore i think that this is maybe not the best example to use
maybe we should have a different example, then, instead of the one that we have here, or add a note to the the diagram's text that Reptiles and Reptilia should not be confused ?
my source for the modern definition of Reptilia is [1]
Playmobil111 ( talk) 15:03, 27 December 2016 (UTC)
References
The article is confused, in my view, because of inconsistent definitions of the three "phylies". Each can be defined in two ways: via the geometry of a cladogram/phylogram, or via the origin of shared characteristics. What's wrong is to define monophyly in terms of geometry, and then contrast it with polyphyly defined in terms of characteristics. Peter coxhead ( talk) 03:05, 17 August 2017 (UTC)
Point taken, (re previous edit: 02:53, 17 August 2017); but edification (for myself) is still needed. Pls review my current revision of the 3rd graphics caption; then review (just below) a further potential revision of the caption---note bold emphasis of the potential new text.
]]File:Phylogenetic-Groups.svg|thumbnail|300px|A cladogram of the vertabrates showing phylogenetic groups. A monophyletic taxon (in yellow): the group of "reptiles and birds", contains its most recent common ancestor and all descendants of that common ancestor. A paraphyletic taxon (in cyan): the group of reptiles, contains its most recent common ancestor, but does not contain all the descendants (that is, Aves) of that common ancestor. A polyphyletic group (in red): the group of all warm-blooded animals (Aves and Mammalia), does not contain the most recent common ancestor of all its members; this group is not considered a taxon by modern systematists.[[
Questions> 1) Is the new text correct re the modern usage of 'taxon'? ..and, 2) In the broad field of taxomony, are there examples of commonly referenced groups that not taxons? Regards.// Jbeans ( talk) 02:04, 28 August 2017 (UTC)
A monophyly is “an arrangement” …. Q> What kind of arrangement? ..what specifics of “arrangement”?
A> .. A monophyly is an arrangement of the members of a “monophyletic” group,
..or, to illustrate the problem:
A> ..A monophyly is an arrangement of the members of a “monophyly-like” group;
---here a modifier (an adjective) of the root word is used in describing the root word; it’s the same ‘loop’ error as when using the root word to define a root word.
Further, even as “monophyletic group” is (previously) described, the reader is still left with: ..a monophyly (the label of this article) is some sort of an “arrangement”---an unexplained arrangement ---that is described by calling upon the adjective form of the root word. This is not ok for Wp!
…Ah, but let me try again. I shall return here---but not before Irma is done with me. Jbeans ( talk) 10:48, 8 September 2017 (UTC)
Look there's been a lot of confused editing in the lead. The thing is this is not improving the article due to differences over monophyly and monophyletic group.
With recent edits these subtle differences have been lost. I suggest we revert to the earlier lead which I feel explained things better. Jules (Mrjulesd) 20:27, 7 November 2020 (UTC)
Some authors hold that holophyly only exists if you consider an organism and all of its descendants– this is very much a minority view now. The standard definition of monophyly is now equivalent to holophyly.
I think we must just agree to differ. As the definition you gave says, any number of things that are located together can make up a group. There's nothing that says they should be brought together. By "clades are defined" you mean "are named". You can't "define" a group of organisms as a clade: they are or they aren't depending on their descent. It's taxa that are defined, not clades. Peter coxhead ( talk) 22:44, 8 November 2020 (UTC)
References
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That's wrong. If H. heidelbergensis and H. neanderthalensis were subspecies of H.sapiens, then they would by definition HAVE common ancestral form, and that wouldn't interfere with monophylecity of Homo in any way. -- Taw
One way or the other, folks, Homo is not a good example. More enlightening quibbles are found in the Dinosauria/Aves cladistics, no?
This entry must mention cladistics/clades to be intelligible. User:Wetman
Portions of this are unintelligible or simply wrong. I'm not sure I'm up to completely rewriting it at the moment, but I will mention the basic problems here in case there is a strong defense of the status quo:
1) Holophyly vs. monophyly. Discussion of holophyly in this article is probable best limited to the current statement "The term is synonymous with the uncommon term holophyly." Yes, there was a brief interest in using the word "holophyly" for what we presently call "monophyly", but this is a minor side issue, while this article seems to suggest that it is the main event. If discussion of this rather defunct debate is necessary, it would best be placed in the article for the term "holophyly", since that term is wholly a creature of that debate, while "monophyly" is not.
2) There are a number of sentences in the article at present, such as "However, when considering taxonomic groups such as genera and species, the most appropriate nature of this common ancestor is unclear. Assuming that this is one individual or mating pair is unrealistic for species, which are by definition interbreeding populations.[1]" and "Naming is also a problem for monophyletic groups: because the number of ancestors from which to root monophyletic groups is almost infinite, giving each clade a unique name is impossible[4] - as illustrated by the failed attempts to instigate a system called the Phylocode. Names obfuscate the really interesting part, which is the branching order, and are therefore of little utility to the cladist [...]" that highlight eccentric objections to cladism. Through their inclusion, they give the impression that the concept of monophyly is shrouded in obscurity and controversy, and are obfuscatory rather than explanatory. An NPOV article should, presumably, attempt to highlight and clarify the mainstream usage and definition of the term. Discussions of disagreement with this mainstream view should not necessarily be removed entirely, but they should not dominate it.
3) Whether a taxon *includes* the common ancestor of the extant members is a somewhat thorny issue that should at least be mentioned in a coherent fashion. At present, the article advocates the inclusion of extinct species within a cladistic classification of extant species without discussion, but also disagrees with itself occasionally; this is not helpful.
4) There seems to be confusion between typological and phylogenetic classifications, e.g.: "For instance, Archaeopteryx appears more reptilian than bird - it has teeth and a number of other reptilian characteristics. But it also has feathers, which have traditionally been considered as an avian trait. It lacks a number of other traits shared by all birds, so can't fall within the bird clade." If Aves is defined phylogenetically, its membership is determined based on the common ancestry of its members and nothing more. Only if Aves is defined typologically are specific traits considered to be necessary and/or sufficient conditions for membership. But in this example, Archaeopteryx is claimed to be excluded from a *clade* (a phylogenetic unit) on the basis of absence of certain characters that are supposedly requisite for membership; i.e., a typological interpretation of taxon membership is applied to a clade. This example is further confused by the problems encountered by attempting to include extinct taxa consistently in a classification of extant taxa, as mentioned above.
5) And a very minor point; calling a clade "a monophyly" is a very unusual construction. I do not think I have ever seen it used in the phylogenetic literature; likely it is out there somewhere, but it is at least anomalous. Paalexan ( talk) 00:19, 15 November 2009 (UTC)
The definition of polypheltic, as distinct from paraphyletic, doesn't make sense to me. Could someone help clear up the following points and/or update the article.
How is possible for the organisms in the group to not have a common ancestral form? If the evolutionary tree really is a tree then this will always be the case, and removing this condition would make no difference to the definition.
Every subset of the set of extant species will always have a latest common ancestor, so what does it mean for a taxonomic group to contain organisms but not their common ancestor?
The difference is whether the last common ancestor is in the group. For instance warm-blooded vertebrates all evolved from the ancestral reptile, but it wasn't itself warm-blooded, so they form a polyphyletic group.
Can anyone translate this into English that a lay person can understand?
I've change the sentence; hopefully the new version makes more sense. Josh
Still incomprehensible. The whole idea of an introduction is so that any reader can understand what the subject is all about. This has not been done. Way too much geekese and insider terminology. - 22:02, 22 February 2010 (UTC) —Preceding unsigned comment added by KitchM ( talk • contribs)
What is it and what is the source of the claim about multiple arisal? This article is the only one in the entire Wikipedia, as well as the internet (according to google), to ever mention such species. mathrick 00:14, 26 November 2006 (UTC)
Since Google corrects the spelling to "Tragopogon miscellus" and gives results about polyploidy and plants in Washington, I posit that "Iragopogen" is a typo. Rehevkor5 23:11, 5 December 2006 (UTC)
Is a monophyletic group basically the same as a clade?23:59, 21 December 2006 (UTC)
I'm interested in getting some comprehensible cladistics articles so I'm going to do an edit. I'm also working on a few others. it's the fine points I'm worried about, the things that make good articles good, etc. What do they got that we ain't got? Fine points. I'll be interested in clarity first. It starts well I do believe. After that the style gets less encyclopedic; maybe it tries to be Stephen Jay Gould - but - out of context. The references - well, I'm pleased to see some. That first reference, can't we have a page number?
So, don't get upset, get helpful. I work very slowly, plenty of time. Dave ( talk) 03:54, 23 January 2010 (UTC)
The early work in cladistics was done in German, and it was translated into English. Sometimes, though, the word that seems the best translation is not used or is not used that way in English, especially if the translator has opted more for transliteration. The words look the same but they aren't the same. For example, we don't speak of the characters of a bird or a reptile - a character is a symbol on a page or a condition of ethical or moral rightness. We call a feature a characteristic. But, in translational contexts, once you understand the author's use of it, character is acceptable. For the clearest English, I want to avoid translational terms and use the regular equivalent. Dave ( talk) 09:08, 24 January 2010 (UTC)
There are such problems with the English of these passages as to render them incomprehensible. First we talk about "appropriate nature." Then we refer to it with an "it" calling it also an individual or a mating pair. I'm sorry, but individuals are not a nature do not have a nature (what is the nature of Tom, Dick or Harry, and are they a nature?) and neither do mating pairs. Only universals have natures: man, bird, mammal, and so on. There is the question of the nature and the question of the common ancestor. They are not identical; you can't mix the two. I presume by nature you mean a synapomorphy. Since when is a synapomorphy? You mean, we can ignore the synapomorphies that are NOT the most appropriate nature? And what happened to the plesiomorphy, or is that what you mean by nature?
In the next paragraph, what do you mean, "doesn't really work?" First the style level is inappropriate. Second, if you mean there is a logical inconsistency, you in no way have stated what that is or even hinted what that may be. I see you are telling us that a "cladistic definition" of a species or genus is "in fact impossible." I seems as though you are trying to say that species and genera cannot be in the stem of a clade. Well, if they can't be, I'd like to know just what can be, as there can't be any more general taxa without the subordinate taxa. But, you might not mean that. Just what you do mean is completely impenetrable.
A third problem is your references. You keep citing Simpson without any page numbers. In other words, we have to search the whole book to try to find out what you mean. This superficial non-reference may satisfy the cursory inspection of a sysadmin in a hurry but it is in no way a reference. In another reference you give us a link to the abstract of an article but that abstract has not a thing to do with the above passages. Maybe the article does, but we can't get that without paying for it. You may not link to pay sites, did you not know that? Whether the article is appropriate I do not know, as I cannot understand what is being referenced. First give us an idea, then give us the reference. No idea, useless reference.
For the moment I'm leaving this passage in to give you a chance to totally rewrite it. This approach has worked well on another article. Then I will look at the rewrite. If you don't respond I will do some additional Internet work to try to find out what problems you are referencing and rewrite it myself. In my experience, I think you would be happiest doing your own work on it, so go right ahead. For the moment I will tackle the next incomprehensible cladistics article. There is no hard and fast rule, cladistics must be incomprehensible to the genral public. Good luck. Dave ( talk) 12:47, 24 January 2010 (UTC)
I have re-written the lead paragraphs to make them both clearer and more accurate. Comments welcome! Peter coxhead ( talk) 10:34, 5 December 2010 (UTC)
There are currently separate articles on monophyly, paraphyly and polyphyly. Inevitably they repeat much of the same material. Worse, they are not wholly consistent with one another (I have been trying to correct this). If there are to be three separate articles, then there is material which is missing from some of them, e.g. each should have a discussion of its advantages or disadvantages in classification. The reality is that you can only understand at least two of these terms (paraphyly and polyphyly) by contrasting them with the others. I am strongly in favour of creating one main article under one of the headings and then having short definitional articles under the other two, which use "see" to point to the main information. I would be willing to try to do this, but not if there is significant opposition. Comments please. Peter coxhead ( talk) 15:54, 6 December 2010 (UTC)
This is one of many WP articles which apparently thinks it is wrong to give a simple example of what is meant. Why not simply put in an example of some animal considered to be monophylatic (and say why) and one which is polyphylatic (and say why)? If a picture is worth a thousand words, then so is an example. To write an article on this subject without ONCE mentioning real instances of what they refer to is silly and pretentious. Myles325a ( talk) 05:48, 23 August 2011 (UTC)
For some time the definition in the lead has been "a monophyletic group is a taxon (group of organisms) which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group." This has recently been altered to "... meaning that it consists of a species and all its descendants."
The minor problem with the new version is the word "species"; this is generally not insisted on by those who use this form of definition. The ancestor could just be a population.
The major problem is explained by Mishler (2009): "There have been two basically different ways of defining monophyly within the Hennigian tradition of phylogenetic systematics: one is synchronic (i.e., “all and only descendants of a common ancestor”); another is diachronic (i.e., “an ancestor and all of its descendants”)." Mishler goes on to prefer the synchronic definition. [See Mishler, B.D. (2009), "Species are not Uniquely Real Biological Entities", in Ayala, F.J.; Arp, R. (eds.), Contemporary Debates in Philosophy of Biology, Oxford, UK: Wiley-Blackwell,
doi:
10.1002/9781444314922.ch6 {{
citation}}
: Unknown parameter |lastauthoramp=
ignored (|name-list-style=
suggested) (
help). There's a more detailed explanation and a suggestion – not taken up alas – for the use of different terminology for the two definitions in Podani, J. (2010),
"Taxonomy in Evolutionary Perspective : An essay on the relationships between taxonomy and evolutionary theory" (PDF), Synbiologia Hungarica, 6: 1–42.]
So I'm not going to revert the change, but actually the original is just as correct as the new version. Sorting this out has been on my to-do list for some time. Peter coxhead ( talk) 11:01, 17 April 2012 (UTC)
{{
cite book}}
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ignored (
help)){{
cite journal}}
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ignored (
help) Though Brochu does consider them different clades, there were not, to his knowledge, any sauropsids contained in either that were not contained in the other. He could not have said a priori that they were not coextensive nor, I suggest, can you confidently predict "that stem-based, node-based and apomorphy-based definitions [will always] correspond to different sets of organisms/fossils/species/whatever."
Peter M. Brown (
talk)
23:26, 18 April 2012 (UTC)This stuff is difficult to explain clearly without example diagrams to refer to (and I accept that some of my verbal explanations, including my use of "branching order", aren't very good). Since I don't want to upload to Commons diagrams which will only be of transient interest, please see here for my attempt to explain more clearly the nature of what Podani (2010) calls "phylogenetic trees" and "cladograms" and how clades can be defined in them.
The difference between "phylogenetic trees" and "cladograms" (or whatever names you call them) is not, in my view, properly explained at present in our set of articles about phylogenetics. Peter coxhead ( talk) 10:56, 19 April 2012 (UTC)
I have deleted from the end of the Monophyly#Definitions section a paragraph reading:
This fails in several ways to meet Wikipedia standards.
All the same, I do not want to delete all reference to a bona fide research tradition. Is there one? Peter Brown ( talk) 23:34, 17 July 2013 (UTC)
The distinction between monophyly sensu cladists and monophyly sensu evolutionists should be clearly and neutrally discussed. Arguments from both sides should be mentioned at least once each. Moreover, the difference between "monophyly" based on set theory (only including terminals) and "monophyly" based on graph theory (including ancestors) should be explained somewhere (see for example Podani 2009; Vanderlaan et al. 2013; Aubert 2015). BernZ ( talk) 09:53, 11 December 2015 (UTC)
the word Reptilia's modern definition in zoology books includes bird (see the wikipedia article on Reptiles, definition section), making it a monophyletic group. this definition is not 100% agreed upon as can be seen by that page's talk page. therefore i think that this is maybe not the best example to use
maybe we should have a different example, then, instead of the one that we have here, or add a note to the the diagram's text that Reptiles and Reptilia should not be confused ?
my source for the modern definition of Reptilia is [1]
Playmobil111 ( talk) 15:03, 27 December 2016 (UTC)
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The article is confused, in my view, because of inconsistent definitions of the three "phylies". Each can be defined in two ways: via the geometry of a cladogram/phylogram, or via the origin of shared characteristics. What's wrong is to define monophyly in terms of geometry, and then contrast it with polyphyly defined in terms of characteristics. Peter coxhead ( talk) 03:05, 17 August 2017 (UTC)
Point taken, (re previous edit: 02:53, 17 August 2017); but edification (for myself) is still needed. Pls review my current revision of the 3rd graphics caption; then review (just below) a further potential revision of the caption---note bold emphasis of the potential new text.
]]File:Phylogenetic-Groups.svg|thumbnail|300px|A cladogram of the vertabrates showing phylogenetic groups. A monophyletic taxon (in yellow): the group of "reptiles and birds", contains its most recent common ancestor and all descendants of that common ancestor. A paraphyletic taxon (in cyan): the group of reptiles, contains its most recent common ancestor, but does not contain all the descendants (that is, Aves) of that common ancestor. A polyphyletic group (in red): the group of all warm-blooded animals (Aves and Mammalia), does not contain the most recent common ancestor of all its members; this group is not considered a taxon by modern systematists.[[
Questions> 1) Is the new text correct re the modern usage of 'taxon'? ..and, 2) In the broad field of taxomony, are there examples of commonly referenced groups that not taxons? Regards.// Jbeans ( talk) 02:04, 28 August 2017 (UTC)
A monophyly is “an arrangement” …. Q> What kind of arrangement? ..what specifics of “arrangement”?
A> .. A monophyly is an arrangement of the members of a “monophyletic” group,
..or, to illustrate the problem:
A> ..A monophyly is an arrangement of the members of a “monophyly-like” group;
---here a modifier (an adjective) of the root word is used in describing the root word; it’s the same ‘loop’ error as when using the root word to define a root word.
Further, even as “monophyletic group” is (previously) described, the reader is still left with: ..a monophyly (the label of this article) is some sort of an “arrangement”---an unexplained arrangement ---that is described by calling upon the adjective form of the root word. This is not ok for Wp!
…Ah, but let me try again. I shall return here---but not before Irma is done with me. Jbeans ( talk) 10:48, 8 September 2017 (UTC)
Look there's been a lot of confused editing in the lead. The thing is this is not improving the article due to differences over monophyly and monophyletic group.
With recent edits these subtle differences have been lost. I suggest we revert to the earlier lead which I feel explained things better. Jules (Mrjulesd) 20:27, 7 November 2020 (UTC)
Some authors hold that holophyly only exists if you consider an organism and all of its descendants– this is very much a minority view now. The standard definition of monophyly is now equivalent to holophyly.
I think we must just agree to differ. As the definition you gave says, any number of things that are located together can make up a group. There's nothing that says they should be brought together. By "clades are defined" you mean "are named". You can't "define" a group of organisms as a clade: they are or they aren't depending on their descent. It's taxa that are defined, not clades. Peter coxhead ( talk) 22:44, 8 November 2020 (UTC)
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