Talk:Animal

Wiki Education assignment: Earth 209 - Introduction to Geology

This article was the subject of a Wiki Education Foundation-supported course assignment, between 3 September 2024 and 13 December 2024. Further details are available on the course page. Student editor(s): Ngumli (article contribs).

— Assignment last updated by Simsdhillon (talk) 02:09, 10 December 2024 (UTC)

Position of Ctenophora

What is the current consensus (if any) on the position of Ctenophora? I've read through a bunch of articles on wikipedia related to the subject, without much to go for it.

I recently found this paper (https://www.nature.com/articles/s41586-023-05936-6 ), and the writers of the paper seem fairly confident that Ctenophora is a sister group to all other animals.

Are there any papers (since 2023) challenging this notion, or is there a consensus starting to form?

Many thanks. IvarTheBoneless123 (talk) 17:22, 30 November 2024 (UTC)

I'd say that if the peer-reviewers of Nature think it's ok then we can safely go along with them. It's not guaranteed to be correct but it certainly looks that way. I'll tweak the article. Chiswick Chap (talk) 19:47, 30 November 2024 (UTC)

I don't think the issue is resolved. Ever since ctenophora-first was first proposed it seems to go in phases with porifera-first or ctenophora-first being recovered depending on the method, with the support usually said to be strong using the favoured methodology. That said, it's been a while since a new study favouring porifera-first, but I've yet to see a review saying it has been resolved to the satisfaction of both camps. I think the way the article currently presents the different theories is a balanced description of the current status and showing the topology of the most recent comprehensive study seems reasonable (an alternative would be to use a figure from a review showing them unresolved).  —  Jts1882 | talk  09:17, 1 December 2024 (UTC)

Yes, thank you. There are several points in the tree that remain contested. We've tried to steer a middle way through the multiple controversies, while presenting the beginning reader with a comprehensible introduction that's reasonably up-to-date. Chiswick Chap (talk) 10:10, 1 December 2024 (UTC)

FWIW, I agree completely with @Jts1882. The Nature study is important, but I doubt consensus has been reached. cyclopia^speak! 11:57, 1 December 2024 (UTC)

In any case, I just found a phylogeny of Opisthokonta published in September that recovers too Ctenophora as the sister group of all other animals. [1] cyclopia^speak! 12:06, 1 December 2024 (UTC)

It seems we all violently agree. I'd be equally interested in people's thoughts about the shape of the article; I've rewritten the Characteristics and ensured the article is fully cited. Is there more that needs to be said? At the moment the article is quite heavily phylogenetic; we could say more about physiology or ecology, for instance, if people feel it's not balanced in some way. Chiswick Chap (talk) 12:22, 1 December 2024 (UTC)

@Chiswick Chap I have a rearrangement in mind that goes something like this: 1) a wider Characteristics section, full of information on physiology, the methods of reproduction, perception, etc. all the basic general stuff covered in the introductions of zoology books; 2) an Ecology section delving into both the roles of animals (primary consumers, predators, parasites, etc.) and their habitat diversity; 3) a Diversity section delving into the current diversity, going through the different animal phyla in a shortened way and noting their species numbers (something in my opinion prettier than a table, although a summarizing table could still be useful); 4) an Evolution section, delving into the fossil record, the origins of animals, and the phylogenetic hypotheses; 5) perhaps a history of classification section, where the vertebrate-invertebrate and coelomate-acoelomate theories could be explained; and lastly 6) a section on the relationship with humans, such as culture, usage, etc. I have been trying to implement this structure in the Protist article and believe it's quite an improvement (still a work in progress, though, but the Diversity section is nearly complete). One big advantage I think this scheme has is that it divides diversity (which is more vast and palatable to the general public who just wants to learn on the different animals that exist) from pure phylogeny (which is more technical and delves into evolutionary theory). — Snoteleks (talk) 13:21, 1 December 2024 (UTC)

Ah, we do have most of that split here, and the article is already rather long ... I thought I was editing Talk:Vertebrate which I've just been working on! Chiswick Chap (talk) 14:12, 1 December 2024 (UTC)

Multiway tree isn't 'consensus'

At the moment we have a tree for 'Internal phylogeny' which shows neither the Porifera as sister hypothesis, nor the Ctenophora as sister hypothesis. An editor has asserted that the tree represents a consensus position, but it's neither a consensus among editors nor among zoologists, it's just a muddle. Worse, There's a new and very bold statement that Giribet and Edgecombe 2020 offers the current zoology consensus, but just above we have 3 sources dated 2019, 2020 and 2023 which support the Ctenophora as sister view, so it's hard to see why we'd suddenly wish to jump to the G&E 2020 conclusion. We clearly need something better here for readers. Chiswick Chap (talk) 14:56, 9 December 2024 (UTC)

It's not supposed to represent consensus, it's supposed to represent a compromise between competing views in lieu of consensus. Mlvluu (talk) 16:36, 9 December 2024 (UTC)

That's not really ok, it isn't a compromise because it just shows a halfway house which makes sense in neither hypothesis, i.e. the Porifera aren't where they should be in the Ctenophora hypothesis, and vice versa. Chiswick Chap (talk) 16:49, 9 December 2024 (UTC)

I can only agree with User:Chiswick Chap. According to the NPOV policy we shall present "all the significant views that have been published by reliable sources on a topic", not a "compromise". IMO all the different views which are not reliably ruled out (all probable hypotheses with reliable sources) should be presented (together with supporting references) separately (i.e. also with separate cladograms). It has no sense to have very detailed cladogram if the very basis is not consensual. A general statement may be added, what seems to be the "mainstream" view, but only with justification (based for instance on the quality or potential obsolescence of references).

We shall accept that there are many unsolved questions in the phylogeny of living organisms (differences between morfological and molecular view, in the interpretation of the molecular data etc. ...) and wait for the scientific consensus in problems such as: Porifera vs. Ctenophora as sister to other animals, Nephrozoa vs. Centroneuralia vs. Orthozoa hypothesis for the base of Bilateria (see cladograms in cs:Dvoustranně souměrní#Taxonomie, even if you probably do not understand the language), several hypotheses for the tree of Spiralia, ... Petr Karel (talk) 16:48, 9 December 2024 (UTC)

Right, well let's do that, though we can't have dozens of detailed cladograms in a top-level overview article. Any help appreciated. Chiswick Chap (talk) 08:40, 10 December 2024 (UTC)

There seems to be a misunderstanding over what a consensus phylogenetic tree represents. A consensus tree shows the known relationships as they are understood and shows the relationships where there is no consensus as polytomies. This doesn't mean a polytomy is the consensus relationship, just that we don't know which is the correct branching order. This is a widely used approach in reviews. By using such a review with such a arrangement, with appropriate explanation, we are following NPOV. Now there has been some progress in more recent primary works (the position of Placozoa seems set), but we shouldn't prioritise primary sources unless they are all in agreement. What we need is a newer review (secondary source) to replace G&E. The alternative is to show the alternative hypotheses, which would probably mean lumping Bilateria and leaving its internal relationships for elsewhere.  —  Jts1882 | talk  08:59, 10 December 2024 (UTC)

Well, sidestepping the interpretation of multiway-splits, I've presented sponge-sister and ctenophore-sister cladograms, and they aren't mirror-images of each other, though as Feuda et al show, they could have been, i.e. there are multiple ambiguities only resolved by showing the actual alternatives. G&E is clearly not satisfactory as you imply. Since in addition neither of these go into detail within the Bilateria, that isn't shown, as you guessed. Chiswick Chap (talk) 09:19, 10 December 2024 (UTC)

That's better. Given the article has subsections on bilateria, protosomes and deuterosomes, Ecdysozoa and Spiralia, I'd suggest a cladogram showing main divisions in Bilateria is still needed (perhaps in the bilateria section).  —  Jts1882 | talk  13:34, 10 December 2024 (UTC)

Yes, the article probably goes too far down into all that stuff, which is the territory of bluelinked articles on all those topics. Chiswick Chap (talk) 13:37, 10 December 2024 (UTC)

I think the Dunn et al (2014) cladogram as it currently appears in the Bilateria article would be suitable in the Bilateria section. Then a brief desciption of the major divisions as written reasonably follows.  —  Jts1882 | talk  13:41, 10 December 2024 (UTC)

Then we'd be pointlessly duplicating Bilateria, causing ourselves what database folk call the double-update problem. We should remove the overlapping text which I foolishly put there some years ago: all of us are vulnerable to the describe-everything temptation. We are already a bit better off than we were (trying to go down to detail all the phyla) but it's still too far really. Chiswick Chap (talk) 13:50, 10 December 2024 (UTC)