Talk:Cnidaria

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Good article Cnidaria has been listed as one of the Natural sciences good articles under the good article criteria. If you can improve it further, please do so. If it no longer meets these criteria, you can reassess it.
January 26, 2009 Good article nominee Listed
          This article is of interest to the following WikiProjects:
WikiProject Animals (Rated GA-class, High-importance)
WikiProject icon Cnidaria is within the scope of WikiProject Animals, an attempt to better organize information in articles related to animals and zoology. For more information, visit the project page.
 GA  This article has been rated as GA-Class on the project's quality scale.
 High  This article has been rated as High-importance on the project's importance scale.
 
WikiProject Marine life (Rated GA-class, Top-importance)
WikiProject icon This article is part of WikiProject Marine life, an attempt at creating a standardized, informative, comprehensive and easy-to-use resource on marine life. If you would like to participate, you can choose to edit this article, or visit the project page where you can join the project and/or contribute to the discussion. This project is an offshoot of the WikiProject Tree of Life.
 GA  This article has been rated as GA-Class on the project's quality scale.
 Top  This article has been rated as Top-importance on the project's importance scale.
 
edit·history·watch·refresh Stock post message.svg To-do list for Cnidaria:

Here are some tasks awaiting attention:
  • Expand : *Morphology and anatomy

Hi Wikipedia! Please check the ratings for the Article. It somehow became 26,000 or more. Thanks!

Priority 2


Cloning?[edit]

The article mentions that cnids can regrow after fragmentation. Would each new cnid be considered a clone of the original cnid? Razor Rozar7 (talk) 22:54, 1 December 2008 (UTC)

Genetically, yes. But in the context of reproduction, cloning is a normal activity rather recovery after a disaster. --Philcha (talk) 23:38, 1 December 2008 (UTC)
So they are technically clones in that each is genetically identical to the original, but they aren't really considered clones? Razor Rozar7 (talk) 00:48, 4 December 2008 (UTC)
I think it's more a peculiarity of the English language - the noun "clones" refers to individuals that are genetically identical (and probably implies "produced asexually", as opposed to "identical twins"), and therefore includes regenerated fragments; but "cloning" (gerund of the verb), when used of a natural rather than lab process, refers to a normal activity rather recovery after an extermally-inflicted disaster. --Philcha (talk) 01:17, 4 December 2008 (UTC)

Reagan link[edit]

The Reagan era link leads to a disambiguation that discusses only the surname Reagan. Does an appropriate article for the biological era exist, or is this entire sentence vandalism?

Classification in the taxobox and the body of the test[edit]

I've played around with trying to clarify the classification of subphyla and classes. I also added links to the source for the classification I used in the taxobox. The problem, of course, is that there are alternative classification schemes. As I am not a worker in the field, I have no feel for what best represents the current state of knowledge. I do feel however, that whatever classification scheme is used in the taxobox should be tied to a source. So, any dissenters to what I've done? -- Donald Albury 12:13, 10 July 2007 (UTC)

Vandalism[edit]

some one is vandalising the page repeatedly!!Silverpal 16:25, 21 September 2007 (UTC)

Headline text[edit]

they allhave stinging cells. more complex than sponges —Preceding unsigned comment added by 67.168.221.157 (talk) 22:56, 29 April 2008 (UTC)

Manus[edit]

The basic body shape of a cnidarian consists of a sac containing a gastrovascular cavity with a single opening that functions as both mouth and anus known as a manus.

I've looked for this term elsewhere and have found no reference to it. It is not used in any invertebrate zoology texts that I've found. Vandalism? --JimmyButler (talk) 15:05, 13 May 2008 (UTC) Corrected ... wow this page is heavily vandalized with very immature edits. Guess it's those school kids doing projects in biology classes.--JimmyButler (talk) 15:20, 13 May 2008 (UTC)

References[edit]

The reference section is not actually considered "references" if they are not sourced within the document. Other than "additional reading" it serves no purpose. Adding a list of stately resources at the end and calling them references does not contribute to the confidence level or the accuracy of the document unless you can determine "what" and "where". That said, several of the references upon, reading, had excellent information that could be included and cited in the article.

I recommend renaming the reference section to Additional Resources or some such nonsense and merging the journal section with it. Then rename the Notes section to "references" which actually have embedded links between the document and the referenced source. Then going through and actually citing the information.

In reality the very long "reading list" should be edited down to those most relevant or useful and the others deleted. People come to Wikipedia for the answer --- not as a hub for an infinite number of links elsewhere.

If no one is opposed, I might dork around with it. I picked up a few skills while being beat up over the Introduction to Evolution FA concerning citations formatting and encyclopedic prose that can help a little here. I'll proceed with care .... don't want to be a Manus about it.--JimmyButler (talk) 01:07, 24 May 2008 (UTC)

Singular vs. plural[edit]

Philcha, this sentence from the lead is grammatically incorrect: "Their distinguishing feature is cnidocytes...".

"Cnidocytes" is a plural word, hence the statement should read "Their distinguishing features are cnidocytes...". However the syntax here implies that cnidocytes are not the only distinguishing feature(s). That's why I changed the text to "They are characterized by cnidocytes..." with the edit summary "Awkward singular/plural conflict changed". Axl ¤ [Talk] 06:45, 18 January 2009 (UTC)

We may have a dialect difference here. "Their distinguishing features are ..." leads me to expect something else as well as cnidocytes, but AFAIK cnidarians have no other features that are unique to them and possessed by all of them. As I said in the edit comment, "distinguishing feature" is plain language for "synapomorphy". --Philcha (talk) 08:57, 18 January 2009 (UTC)--Philcha (talk)
You have completely missed my point. I agree with your second sentence (as I commented above), which is why that is not what I recommended. As I said, both in my edit summary and my comment above, the problem lies with the mixed use of singular and plural forms in the sentence. Axl ¤ [Talk] 10:27, 18 January 2009 (UTC)
Re "the mixed use of singular and plural forms in the sentence", that could be resolved by "... is the possession of cnidocytes, ...", but I think the cure would be no better than the disease, because of the extra verbiage. --Philcha (talk)
Indeed I was considering "... the presence of cnidocytes...". ;-) While the phrase is longer, it is grammatically correct. Axl ¤ [Talk] 13:15, 18 January 2009 (UTC)


Congratulations[edit]

Congratulations on the GA for Cnidaria. This article generated some interest for me as well as my students a year ago in that a statement concerning Manus (mouth anus system) had languished there for some time. The need to correct this rather humorous factoid is what broke my self imposed Wiki-bann. It is such a delight to see the article tranformed so dramatically. Especially since the topic is probably high volume for high school students doing research on animal phyla. The before and after snap shot on this one speaks volumes about the work invested. Thank you. --JimmyButler (talk) 03:18, 27 January 2009 (UTC)

"An idiom is a phrase where the words together have a meaning that is different from the dictionary definitions of the individual words, which can make idioms hard for ESL students and learners to understand." ummm .... Conversely? But your right .... in the scheme of the transformation that took place here it is a non-issue! Cheers--JimmyButler (talk) 03:30, 27 January 2009 (UTC)

Number of species[edit]

I just undid a change in number of species in lead from 9,000 to 11,000:

  • Not as shown in main text - see WP:LEAD.
  • No source given - see WP:V and WP:CITE.
  • Species counts are tricky. Those given in the article are based on formally-recognised species ("described" in the jargon) by class (jellyfish, anemones, etc.) To replace the count in the lead you'd have to find a source that gave other counts by class - one source, as summing counts of different classes by different authors would be like adding apples and oranges. --Philcha (talk) 13:24, 25 June 2009 (UTC)

Etymology?[edit]

I'm inserting a request on the talk pages for Ctenophore and Cnidaria to add an Etymology section. The "silent c" is uncommon enough in language that I'd be very interested to know where it comes from.174.46.172.13 (talk) 09:30, 19 August 2009 (UTC)

I've added a link at the bottom of the page to the Wiktionary entry for Cnidaria, which indicates that it is derived from the Ancient Greek word for 'nettle'. -- Donald Albury 10:13, 19 August 2009 (UTC)
See Cnidaria#Cnidocytes. --Philcha (talk) 11:38, 19 August 2009 (UTC)

question on redirect[edit]

According to the Taxonomicon Cnideria [1]is a phylum with Anthozoa and Medusazoa as subphyla. So why is Medusazoa redirected to Cnideria. Perhaps discussion particular to medusazoans should be removed and included in a separate article for that group. J.H.McDonnell (talk) 22:45, 18 October 2009 (UTC)

I agree that Medusozoa should have its own article rather than being redirected to Cnidaria. However material shoudl not be removed from Cnidaria, as this article is meant to be an overview of the whole phylum. --Philcha (talk) 06:12, 19 October 2009 (UTC)


Over 9000[edit]

Is this actually correct or just "for deh lolz"? --68.158.0.237 (talk) 16:41, 1 November 2009 (UTC)

It's for real, from a good source that counts only confirmed species rather than estimates - see details at Cnidaria#Classification. --Philcha (talk) 18:16, 1 November 2009 (UTC)


Primitive[edit]

"cnidarians, although considered more "primitive" than bilaterians, have a wider range of genes, and that bilaterians have introduced few new genes and that most have lost several—this reduction is most striking among the ecdysozoan group of protostomes, which includes arthropods and nematodes.[44] In fact cnidarians, and especially anthozoans (sea anemones and corals), retain some genes that are present in bacteria, protists, plants and fungi but not in bilaterians."

Use of "although" seems to imply that what follows contradicts the idea of cnidarians being more primitive than bilaterians. But anything found in "bacteria, protists, plants and fungi but not in bilaterians" is most certainly a primitive trait (=found in common ancestor though perhaps lost in some descendants) for animals. I understand the intent here -- that some people think of "primitive" as "more simple/crude" -- but I think this rather adds confusion than clarifies, by somewhat confusing the biological definition of primitive (primitive characters = those found in common ancestor, as opposed to derived characters) with the colloquial meaning. I think simply removing the clause "although considered more 'primitive' than bilaterians" would be best. Vultur (talk) 09:00, 25 January 2010 (UTC)

IIRC the pattern in which primitive organism have more wider range of genes than their derived descendants is quite common, and this point should therefore be retained. How about e.g. "cnidarians are considered more primitive than bilaterians but have a wider range of genes, while bilaterians have introduced few new genes and most have lost several—this reduction is most striking among the ecdysozoan group of protostomes, which includes arthropods and nematodes.[44] In fact cnidarians, and especially anthozoans (sea anemones and corals), retain some genes that are present in bacteria, protists, plants and fungi but not in bilaterians." --Philcha (talk) 10:51, 25 January 2010 (UTC)
The statement that "bilaterians have introduced few new genes" seems highly misleading. Genes (in the sense of protein-coding sequences) don't come from nowhere (at least this would be exceptionally rare), so any modern gene derives from some ancestral gene -- but bilaterians have millions of genes that are not found in other organisms. Maybe a less misleading statement would be that bilaterians have lost more ancestral genes than cnidarians have? Looie496 (talk) 17:35, 25 January 2010 (UTC)
"In fact cnidarians, and especially anthozoans (sea anemones and corals), retain some genes that are present in bacteria, protists, plants and fungi but not in bilaterians" is based on ref [45] and looks very solid.
The first sentence, "cnidarians are considered more primitive than bilaterians but have a wider range of genes, while bilaterians have introduced few new genes and most have lost several ..." is based on ref [44], but that surveyed one family genes. I'll check this outside in more detail today, when I'll now at home and can use my main computer. --Philcha (talk) 21:59, 25 January 2010 (UTC)
I agree that the sentence based on ref 45 is okay, the issue is with the other one. It's really a question of what counts as a "new gene". Since no gene remains fully invariant over time, and every gene derives from some ancestor, no gene is ever either purely new or purely old, so there is bound to be some arbitrariness about this. With the current wording, I don't think many readers will understand the sentence correctly. Regards, Looie496 (talk) 22:39, 25 January 2010 (UTC)
A slightly fascinated, but not unrelated aside. The issue of it being not uncommon for earlier lifeforms to have a wider range of genes than their descendants appears to be consistent with Stephen Jay Gould's argument pertaining to reduction in disparity as measured by both the lack of new "body plans" over time and the lack of any major modifications of old ones.
On the evolution of new gene variants, I wouldn't have thought this was particularly controversial. It would come down to how a new gene is defined. I guess that this varies in the literature, with some focusing more on the gene structure, and some more on the function. And I guess it's easier to see this in literature on organisms where it's easiest to study phylogenetic change. Such as those with short lifespans and rapid replication, like micro-organisms and good old Drosophila melanogaster. Just a loose hypothesis on my part for comment if you see fit (doesn't matter if you don't, if I'm around long enough, I'll check it out myself, having created a question for myself). Wotnow (talk) 08:52, 26 January 2010 (UTC)

Second paragraph in lede[edit]

I tend to write long, multi-clause sentences myself, but I found the following sentence hard to follow, and had to read it several times to be sure I understood it:

Cnidarians are classified into four main groups: sessile Anthozoa (sea anemones (not sessile but only move 3-4 inches an hour), corals, and sea pens); swimming Scyphozoa (jellyfish); Cubozoa (box jellies); and Hydrozoa, a diverse group that includes all the freshwater cnidarians as well as many marine forms, and has both sessile members such as Hydra and colonial swimmers such as the Portuguese Man o' War.

Basically, it looks like two of the groups are identified as "sessile" and "swimming", and then the scheme shifts to using orders. There are too many asides, as well. There is a shorter and simpler version of this sentence in the "Classification" section. Neither the sentence in the lede nor the one in the "Classification" section agrees with the classification in the taxobox. The lede should be a summary of the article. I'm not sure that the classification of members of Cnidaria needs to be included. A simple list of some easily recognizable members (i.e. anemones, corals, sea pens, and jellyfish) should be sufficient for the lede. -- Donald Albury 11:41, 28 March 2011 (UTC)

Hi, Donald Albury. That para is about classification, not locomotion. I've edited to "the almost wholly sessile Anthozoa (sea anemones, corals, sea pens); swimming Scyphozoa (jellyfish); Cubozoa (box jellies); and Hydrozoa, a diverse group that includes all the freshwater cnidarians as well as many marine forms, and has both sessile members such as Hydra and colonial swimmers such as the Portuguese Man o' War." --Philcha (talk) 12:47, 6 April 2011 (UTC)
The taxobox has one view of the taxonomy. The Taxonomicon gives no citations, authors, etc., so by WP:V it's not a 1st-class source. It is more consistent with the cladogram at Cnidaria#Family_tree. But cladistics, and especially molecular phylogeny is turning up traditional taxonomy and this may make taxoboxes obsolete. --Philcha (talk) 12:47, 6 April 2011 (UTC)
I doubt taxoboxes are going away. Competing classifications are found in many articles about life forms, and we don't have a consistent way of presenting them, but infoboxes of all kinds seem to be firmly imbedded in WP culture. -- Donald Albury 12:58, 6 April 2011 (UTC)

"more complex" sentence[edit]

"Cnidarians form an animal phylum that more complex than sponges, about as complex as ctenophores (comb jellies), and less complex than bilaterians"

An unclear sentence. It's written to say that the phylum is more complex, but appears to mean that the animals of the phylum are individually more complex. — Preceding unsigned comment added by 144.118.94.176 (talk) 01:36, 5 December 2012 (UTC)

Polymorphism[edit]

After reading that section that was created again, polymorphism isn't specifically about zooid differentiation, which confused the topic by suggesting that colonial zooids were the same as medusa and polyp forms in all cnidarians. I reworked it a bit to be more clear. Esoxidtalkcontribs 22:04, 29 April 2014 (UTC)

Wrong evolutionary tree and a lack of Myxozoa[edit]

Lately Myxozoa has been shown to be a Cnidarian (as can be seen on the Myxozoa page on Wikipedia), yet that is not discussed in the evolutionary history. Also - they are more likely closer to Medusozoa than Anthozoa, so they should be deep within the Cnidarian tree and not next to Bilateria at all (the whole bilaterian debacle was because of fish fragments in the Myxozoa DNA). I don't know how to edit Wikipedia well, so I think someone should change that. — Preceding unsigned comment added by Erez87 (talkcontribs) 12:53, 6 June 2016 (UTC)