Talk:Alternation of generations

message: I've been reading and re-reading your suggested text changes, and think I've come across one specific issue that could be clarified.  You are assuming that the terms "generation" and "completion of a life cycle" are necessarily one and the same. They are not.  A life-cycle is a complete turn through the stages of organismal reproduction from one point back to that same point.  I think we agree on that as a definition, at least.  A generation, however, is the production of a multicellular organism from a single cell. This happens twice in organisms with a haplo-dipontic or a diplo-haplontic life cycle, since both the zygote and the spore undergo multiple mitotic divisions, to produce the diploid sporophyte and haploid gametophyte, respectively. The two terms are indeed synonymous among animals (and all organisms with a haplontic or diplontic life-cycle), but only because the life cycle includes a single multicellular stage.  -- EncycloPetey 04:43, 18 November 2005 (UTC)
replies: text: I just do not think (at this point) that your definition of generations is necessarily the generally accepted one (although I do see your point). I've run across the ideas, multiple times, that in "alternations of generations" generations is defined differently (quote I gave above) and that it should be alternation of phases within a generation to be correct.  Obviously, the "problem" does revolve around that definition, which seems to be not generally fixed among biologists.  But even your sources (you quoted above) used "phases" (in addition to generation in one case, presumably to satisfy both "camps"). While I agree, the term usually used is "alternation of generations", to call the gametophyte of the higher plants another generation becomes a real stretch (another phase within the generation is a lot cleaner). I think it is an idea some botanists like to promote (Fosket, 1994 for example) because it connjurs up an interesting picture of the gametophyte being "captured" by the sporophyte over evolutionary time; but that is just a metaphore.  One can also view it as simply the reduction of importance of the gametophyte phase to its basic functions, paralleling animal evolution. Obviously with such confusions between botanists and everyone else and within botany itself, it is safest to avoid the term "generation"; but we cannot do that, because it is in the article title (for good reason).  Therefore I suggest the "explanatory" approach I have been e3diting towards. That includes pointing out the conflicting definitions of "generation" used by biologists. It might help to first get the life cycle article tuned up.  - Marshman 18:12, 18 November 2005 (UTC)
thread_title: Life-cycle vs generation

message: I think that having more diagrams to illustrate the various types of alternation of generations (ie: moss, gymnosperms, angiosperms) would make this article more readily understood. Alex Ng 04:23, 4 May 2006 (UTC)
replies: text: Be BOLD and add images that are already located in the various sub-articles on groups of plants. In particular, LadyofHats has done some very nice diagrams, and might be asked to do a few more. --EncycloPetey 09:05, 4 May 2006 (UTC)
thread_title: More Diagrams?

message: The real problem is that there are not enough examples. Experts in the subject have a bunch of examples in their heads that keep all these ideas straight; regular folk scratch their heads and don't see how it all fits together. For example, in plain language how do the apple trees in my yard go through this process? What are the different stages?? How do the flowers fit into this system? How does moss pass through this process? It just isn't clear to non experts. The article may be accurate but it is completely worthless to a high school freshman trying to read her biology text.
I agree that it would be nice to have more direct examples that could help those who have a good general biology understanding but a small plant reproduction understanding keep their ideas straight. However, finding examples that have been cited as correct in literature could be a harder task than one might expect. 19345beta (talk) 02:12, 20 September 2020 (UTC)
thread_title: More examples would be nice 

message: Should it not be "all vascular plants" ? I do not know exceptions but the introduction suggests that it is rare. From what I have read there is always alternation of generations, the timespan/length of the haploid and diploid stages however vary.  Shyamal 03:59, 4 December 2006 (UTC)
replies: text: Oops, looks like this has been discussed in the threads above. But the final introduction is still not satisfactory as per the earlier discussion. Shyamal 12:10, 4 December 2006 (UTC)

text: This has still not been cleared up. The article refers to "certain plants", and then below in the section "vascular plants", only "ferns and their allies" are mentioned. This implies that other vascular plants do not exhibit alternation of generations, contrary to what I thought was the case, although I'm not a botanist and I'm not sure. I suggest that a clear statement should be made one way or the other, either "most other vascular plants exhibit alternation of generations also", or "most other vascular plants do not exhibit alternation of generations". Bayle Shanks 03:34, 14 July 2007 (UTC)
replies: text: Strangely, I too noticed that this has not been fixed just now and was further surprised by the GA status. I would think this article needs rework on citations, layout and wording. Unfortunately my botany is a little weak and rusty for this. Shyamal 03:40, 14 July 2007 (UTC)
thread_title:  All or some vascular plants 

message: Members of the Wikipedia:WikiProject Good articles are in the process of doing a re-review of current Good Article listings to ensure compliance with the standards of the Good Article Criteria. (Discussion of the changes and re-review can be found here). A significant change to the GA criteria is the mandatory use of some sort of in-line citation (In accordance to WP:CITE) to be used in order for an article to pass the verification and reference criteria. Currently this article does not include in-line citations. It is recommended that the article's editors take a look at the inclusion of in-line citations as well as how the article stacks up against the rest of the Good Article criteria. GA reviewers will give you at least a week's time from the date of this notice to work on the in-line citations before doing a full re-review and deciding if the article still merits being considered a Good Article or would need to be de-listed. If you have any questions, please don't hesitate to contact us on the Good Article project talk page or you may contact me personally. On behalf of the Good Articles Project, I want to thank you for all the time and effort that you have put into working on this article and improving the overall quality of the Wikipedia project. LuciferMorgan 02:05, 25 January 2007 (UTC)
thread_title:  GA Re-Review and In-line citations 

message: Reference in the text to this phenomena in the Cnidaria (medusa to polyp forms) needs to be made   Goldfinger820 05:38, 13 July 2007 (UTC)
replies: text: Please elaborate on it, then. Speciate 06:03, 13 July 2007 (UTC)

text: If you will provide references to these textbooks, I can probably acquire them and add the information.  The invertebrate texts I have available do not use this terminology. --EncycloPetey 20:16, 15 July 2007 (UTC)
replies: text: although not a invertebrate only text, "Zoology  Miller S.A and Harley, J.B. (1999) 4th ed  IBSN 0-697-34555-6" has a reference to Cnidarian AoG on page 269. it is used here as a subtitle to describe the change in body form (but as you correctly point out -not in ploidy).  will try to find some other refs if I get some time  cheers Goldfinger820 04:44, 14 August 2007 (UTC)
thread_title: Cnidaria

message: :This discussion is transcluded from Talk:Alternation of generations/GA1. The edit link for this section can be used to add comments to the reassessment.
===GA Sweeps: Delisted===
As part of the WikiProject Good Articles, we're doing sweeps to go over all of the current GAs and see if they still meet the GA criteria. I believe the article currently has multiple issues that need to be addressed, and as a result, I have delisted the article. Although several references are listed, there are no inline citations for large portions of the article's content which is required under the criteria. Add additional citations from a variety of sources to provide a balanced representation of the information present. Perhaps sources can be pulled from the main articles linked to within the article. Look to books, magazines, newspaper articles, other websites, etc. In addition, per WP:GALLERY the galleries should be removed and the images placed on the sides of the article content. Although the article has been delisted, the article can be return to GA status by addressing the above points. Once sources are added and cleanup is done, I recommend renominating the article at WP:GAN or you can contact me on my talk page and I'll review it for you so you can bypass the month-long backlog. If you need assistance with any of these issues, please contact me on my talk page and I'll do my best to help you out. --Happy editing! Nehrams2020 (talk • contrib) 01:56, 3 June 2009 (UTC)
thread_title: GA Reassessment

message: As part of the WikiProject Good Articles, we're doing sweeps to go over all of the current GAs and see if they still meet the GA criteria. I believe the article currently has multiple issues that need to be addressed, and as a result, I have delisted the article. Although several references are listed, there are no inline citations for large portions of the article's content which is required under the criteria. Add additional citations from a variety of sources to provide a balanced representation of the information present. Perhaps sources can be pulled from the main articles linked to within the article. Look to books, magazines, newspaper articles, other websites, etc. In addition, per WP:GALLERY the galleries should be removed and the images placed on the sides of the article content. Although the article has been delisted, the article can be return to GA status by addressing the above points. Once sources are added and cleanup is done, I recommend renominating the article at WP:GAN or you can contact me on my talk page and I'll review it for you so you can bypass the month-long backlog. If you need assistance with any of these issues, please contact me on my talk page and I'll do my best to help you out. --Happy editing! Nehrams2020 (talk • contrib) 01:56, 3 June 2009 (UTC)
thread_title: GA Sweeps: Delisted

message: I believe this applies to animals too -- if not nearly all eukaryotes. Animals simply have a very reduced form of alternation of generations, after all. 128.143.102.189 (talk) 05:11, 13 October 2010 (UTC)
replies: text: This is discussed at some length in the article (especially the "Distinctions" section). If you think that section is incorrect, please supply some references. Kingdon (talk) 11:25, 17 October 2010 (UTC)

text: It could only be a "reduced" form if the ancestor of animals had such a life cycle.  Current scientific opinion is that alternation of generations has arisen independently multiple times, but that it was not present in the common ancestor of animals. --EncycloPetey (talk) 05:11, 18 October 2010 (UTC)

text: This is a very good point, and I have edited the article to try to account for this. As the IP editor notes, haploid males and diploid females is not alternation of generations because males are always haploid and females diploid, but it does mean that it can't be said that "all animals are diploid". Peter coxhead (talk) 16:11, 17 May 2017 (UTC)
thread_title:  Animals 

message: I have undertaken a major re-write and expansion of what seems to me to be an important article which previously had some serious faults, as noted above. Some more material is needed, particularly in the section on the life-cycles of different plant groups. Comments and edits welcome! (At least copy-editing is doubtless needed.) Peter coxhead (talk) 20:48, 1 January 2011 (UTC)
thread_title:  Major re-write 

message: If we look up "metagenesis" in Wikipedia, it redirects to "alternation of generations".  But it has a totally different meaning in petroleum geology:
: metagenesis
:1. n. [Shale Gas]
:The last stage of maturation and conversion of organic matter to hydrocarbons. Metagenesis occurs at temperatures of 150° to 200°C [302° to 392°F]. At the end of metagenesis, methane, or dry gas, is evolved along with nonhydrocarbon gases such as CO2, N2, and H2S, as oil molecules are cracked into smaller gas molecules.
We should have a separate page for metagenesis, with the main entry to this page "alternation of generations", and another entry for the geological meaning.173.10.202.66 (talk) 21:05, 20 February 2017 (UTC)
replies: text: Most botanists call it Alternation of generations rather than metagenesis, so probably it would be better to keep that article as it is. One option is to convert Metagenesis to a disambiguation page and create a new article with a title like Metagenesis (geology). An alternative would be to make the Metagenesis article exclusively geological but to have a hatnote directing the biologist who arrives there to Alternation of generations. Plantsurfer 21:24, 20 February 2017 (UTC)

text: I'd vote for the last option, making the Metagenesis article entirely about geology, with a hatnote. Sminthopsis84 (talk) 10:27, 25 February 2017 (UTC)

text: I agree with Sminthopsis84. Peter coxhead (talk) 20:25, 25 February 2017 (UTC)
thread_title: Problem with dual meaning of Metagenesis

message: This article (Permalink) Misleads potentially. 
* Firstly, this article contain a little bit about animal's metagenesis. And animal's metagenesis is conceptually the same with plant's alternation of generation. There is no need to separate them. 
* Secondly, Heterogamy is never similar with alternation of generation. The only similarity is both are related to reproduction. 
* As well as heterogamy (heterozygosity) takes place in plants too. We can see heterogamous pea seedlings in Mendel's experiments. The linked article,  Heterogamy, also mentioned several othe different usage of heterogamy, i.e. 1. "In cell biology, heterogamy is a synonym of anisogamy, the condition of having differently sized male and female gametes produced by different sexes or mating types in a species." and 2. "In botany, a plant is heterogamous when it carries at least two different types of flowers in regard to their reproductive structures, for example male and female flowers or bisexual and female flowers. Stamens and carpels are not regularly present in each flower or floret.". But they are found in plants. 
If you are human-like but your daughter/son is box-like and your grand-daughter/grand-son is again human like, that could be called an alternation of "generations". There is nothing to do with heterogamy. 
18:31, 18 September 2017 (UTC)
replies: text: The term "heterogamy" has more than one meaning. The reason for separating animals is that they do not undergo a regular alteration of generations with differing ploidy levels consistent with the alternation of those generations. The two can be conceptually linked, yes, and that is done at biological life cycle. This article treats only of the alternation as it exists when accompanied by regular changes in ploidy. --EncycloPetey (talk) 00:11, 19 September 2017 (UTC)
thread_title:  The initial statement, "This article describes alternation of generations in plants; for a similar phenomenon in animals see Heterogamy" is wrong.  

message: The following Wikimedia Commons file used on this page or its Wikidata item has been nominated for speedy deletion:
* 
You can see the reason for deletion at the file description page linked above. —Community Tech bot (talk) 19:22, 25 March 2022 (UTC)
thread_title:  A Commons file used on this page or its Wikidata item has been nominated for speedy deletion 

message: The following Wikimedia Commons file used on this page or its Wikidata item has been nominated for deletion:
* 
Participate in the deletion discussion at the . —Community Tech bot (talk) 21:37, 25 March 2022 (UTC)
thread_title:  A Commons file used on this page or its Wikidata item has been nominated for deletion 

message: I have added the technical template. I think it would help to have an simple example for a plant most people would recognize, even if that doesn't cover all cases. Also, it would be helpful to mention how frequent the alternation of generations is in the major plant divisions. Unfortunately I don't know enough about the topic to be of much help. Vpab15 (talk) 12:12, 1 April 2022 (UTC)
replies: text: Alternation of generations is the norm for plants and algae. The phenomenon is often illustrated using the life cycle of a fern, in which the asexual sporing stage or sporophyte is the familiar fern, and the sexual gametophyte stage is the prothallus. Plantsurfer 20:47, 1 April 2022 (UTC)

text: Yes, the article is rather technical, but it seems to me that this is a rather technical subject. (Note the quote in the article: "the alternation of generations has become a terminological morass; often, one term represents several concepts or one concept is represented by several terms.") It could be introduced differently, e.g. for land plants by describing the fern lifecycle earlier, since (as Plantsurfer notes above) this is clearer as both the sporophyte and gametophyte are macroscopic. Peter coxhead (talk) 10:20, 2 April 2022 (UTC)
replies: text: I think it would be helpful to compare the process to that of animals. As I understand for seed plants the main difference is the way gametes are produced by mitosis in plants rather than meiosis. But that seems more like a small detail rather than a fundamentally different reproduction process. The gametophytes do not have an independent existence from the parent plant. Since seed plants are the type of plant most people are familiar with I think we should stress more the similarity of the process and not focus so much on the differences. Vpab15 (talk) 21:59, 2 April 2022 (UTC)
replies: text: No, the underlying difference is still quite major even if not apparent. People sometimes think of pollen as equivalent to sperm, for example, but it is not. Pollen may be a very reduced gametophyte, but it is still capable of growth, germinating and producing a pollen tube and gametes which move down the pollen tube. The pollen does have an independent existence from the parent plant – only the female gametophyte doesn't. By contrast, animals produce sperm directly, and the sperm is not capable of growth or division. Peter coxhead (talk) 08:33, 3 April 2022 (UTC)
replies: text: To help readers understand a concept, it usually helps to link it to something they already know. In this case animal reproduction. I think we don't need to stress those differences in the intro, they can be explained later in the body. Vpab15 (talk) 09:19, 3 April 2022 (UTC)
replies: text: But the whole point is that a lifecycle with alternation of a diploid sporophyte generation and a haploid gametophyte generation is radically different from a life cycle with only a diploid generation. So the "link" to animal reproduction is that it's different, not that it's the same. Peter coxhead (talk) 20:39, 3 April 2022 (UTC)
thread_title:  Article is too technical