Talk:Animal

Number of described living species?
The article lead says "2.16 million species" as of 2022, yet there is no reference for this in the text. The only data present is around 1.5 million as of 2013, in the Diversity section. —Snoteleks (Talk) 13:31, 4 September 2023 (UTC)
 * Apart from the lack of a source for this in the article, I'll complain about the precision. There is no estimate of animal species with three significant figures. I wouldn't give more precision than saying there are more than 2 million species, assuming a source can be found. That aside, there can be no reliable estimates as most species haven't been formally described. Estimates for insect species numbers for groups like beetles have them several fold higher than the number of described species. A quick google finds a National Geographic article on Biodiversity, which says that "Scientists have estimated that there are around 8.7 million species of plants and animals in existence. However, only around 1.2 million species have been identified and described so far, most of which are insects". I think I've seen sources for over one million described insect species. I'll dig a bit deeper. —  Jts1882 &#124; talk 16:16, 4 September 2023 (UTC)
 * The IUCN estimates 74,420 described vertebrates and described invertebrates 1,521,459 pdf, which adds up to about 1.6 million described animals. The pdf breaks it down further, e.g. 1.05 million insects, 114m molluscs, 111m arachnids, and 80m crustaceans. The IUCN estimates 2.16m for total eukaryotes, which looks suspiciously like the number in the lede. —  Jts1882 &#124; talk 16:38, 4 September 2023 (UTC)
 * The 8.7m comes from Mora et al (2011). and gives 7.8m total for animals, based on 960k species described. —  Jts1882 &#124; talk 16:45, 4 September 2023 (UTC)
 * For another data source (taken for what it's worth), the GBIF global taxonomic "backbone" data set presently recognizes as "accepted" over 2.6 million species. Note that this does exclude all synonyms, which are not flagged as "accepted" in GBIF, nor any records GBIF classifies as "doubtful". As such, this should be a very CONSERVATIVE estimate of the number of described species. I'd go so far as to say for every name incorrectly recognized as "accepted" in GBIF, there is more than one name NOT recognized as accepted that should be. Unfortunately, the GBIF raw records don't appear to display Kingdom, unless it's in encoded form, so I can't tell you the exact proportion that are animals. It also doesn't seem to give any indication as to how many of the species are extinct. If I can dig a little deeper into the data file, I may be able to clarify one or both of these points, and if so, I'll update the note. For now, I think the estimates of only 1.2 million is a vast underestimate for described species. It's certainly over 2 million, even if all the extinct taxa are excluded. Dyanega (talk) 17:00, 4 September 2023 (UTC)
 * I figured out which field contained the codes for Kingdom; there are between 1.8 million and 1.9 million "accepted" Animalia names in GBIF. Using known extant/extinct taxa as reference points, however, I can't see any codes that would correspond, so I don't think GBIF is tracking this. Dyanega (talk) 20:36, 4 September 2023 (UTC)

We should state what all animals have in common without exception.
The second sentens says: “With few exceptions, animals consume organic material, breathe oxygen, have myocytes and are able to move, can reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development.”

We should state what all animals have in common without exception. I know that some animals don’t move much, but which of the other five things mentioned are not common to all animals?

We should write two sentences, like this: “All animals… With few exceptions…” What should go in the first and second sentence?

Jan Arvid Götesson (talk) 08:29, 29 January 2024 (UTC)


 * Thanks for asking. Unfortunately it's the old schoolbook definition approach, with no answer. Animals have one thing in common: their ancestry, as they firm a clade. But this doesn't translate into any easy set of qualities which have been gained and lost over time. All the best, Chiswick Chap (talk) 08:42, 29 January 2024 (UTC)
 * But there must be something that all animal have in common, and is interesting enough to mention? Jan Arvid Götesson (talk) 08:48, 29 January 2024 (UTC)
 * Not even “breathe oxygen” is common to all animals. Henneguya zschokkei does not. That leaves only “consume organic material”, “can reproduce sexually”, and “grow from blastula” on the potential list. — Preceding unsigned comment added by Jan Arvid Götesson (talk • contribs) 07:31, 30 January 2024 (UTC)
 * I repeat, it's a futile approach, both non-biological and frankly unencyclopedic. Let's just give it a try: Reproduce sexually or asexually; respire aerobically or anaerobically; are terrestrial or aquatic; microscopic or macroscopic; parasitic or free-living; motile or sessile; having bilateral, radial, or pentamerous symmetry, except possibly sponges which might be entirely asymmetric; heterotrophic except for corals which have photosynthetic endosymbionts; etc. etc. etc. Really, no, thankyou, this isn't the way to go. It just isn't how we should be trying to write an even slightly scientific encyclopedia. Once again, this is not a circa-1900 elementary schoolbook laying down the law about all life being divided into animals and plants, all metabolism being either oxidative respiration or photosynthetic primary production: it all just isn't like that. Let's just drop it, please. Chiswick Chap (talk) 20:27, 30 January 2024 (UTC)
 * @Jan Arvid Götesson Animals are the most diversified described group, it's not a surprise that there are tons of exceptions. The text already states their main synapomorphy: blastula stage during embryonic development. Other characteristics (according to Adl et al., 2019) are: "sexual reproduction through an egg cell usually fertilized by a monociliated sperm cell with acrosome; gastrula phase that follows the blastula and allows differentiation into endoderm, ectoderm and mesoderm" (we should check if sponges share this) "basal lamina and extracellular matrix with collagen and other fibrous proteins; heterotrophic nutrition with secretion of digestive enzymes and osmotrophy through a digestive tract; ectoderm completely surrounding body, and endoderm surrounding a digestive tract; sensory cells in epithelium; nervous tissue in organized network; epithelial actin–myosin-based contractile cells between endoderm and ectoderm;" etc. —Snoteleks (Talk) 08:37, 31 January 2024 (UTC)
 * Indeed, and none of those complex technical details are remotely suitable for the lead, which is not just a summary but introductory for beginning-level readers. Chiswick Chap (talk) 08:55, 31 January 2024 (UTC)
 * @Chiswick Chap Agreed. Also some of those aren't even synapomorphies, like the collagen thing and cell-cell junctions, since they appear in Holozoa as a whole. —Snoteleks (Talk) 17:11, 31 January 2024 (UTC)
 * Well, exactly. Chiswick Chap (talk) 17:13, 31 January 2024 (UTC)

Wiki Education assignment: Introduction to Community Economic and Social Development II
— Assignment last updated by Rajandeep Kaur Dhaliwal (talk) 04:21, 12 February 2024 (UTC)

Numbers and habitats of major phyla
Under the heading "Numbers and habitats of major phyla" there's a table that presents the phyla in descending order by number described species. I suggest, in the interest of presenting good information, they be ordered phylogenetically.

Also, someone should either, `1) add a column that describes the points of increasing adaptive complexity, or 2) add a table for just this purpose. Krisandtim (talk) 03:32, 11 March 2024 (UTC)
 * I've made the table sortable under the name and the number of species columns. To get the number of specie column to work I added a sort key using . Some other columns could be made sortable with appropriate sort keys.
 * What measure would you need for "adaptive complexity"? This would have to be sourced. —  Jts1882 &#124; talk 07:36, 11 March 2024 (UTC)
 * Surely unworkable. Sounds like "higher" and "lower" by any other name. But it would be nice to have all the other columns sortable in a Boolean (yes/no) way if that can be arranged. Chiswick Chap (talk) 08:27, 11 March 2024 (UTC)
 * I didn't make the other columns sortable as they have a mix of yes, blanks and numbers and give a strange order. The numbers with references are treated as stings, which is why they need sort keys. Are all the blanks noes? Perhaps those columns should all have yes or no with the numbers in parenthesis. To make the column sortable, remove the  from the column headers.
 * Yes, blanks are noes, so we can begin all with yes or no followed by (details). The free-living column can't be sorted as it's all yeses, so not a lot of use in that instance. Chiswick Chap (talk) 10:53, 11 March 2024 (UTC)
 * Also, can we do better than the 2013 reference? —  Jts1882 &#124; talk 10:42, 11 March 2024 (UTC)
 * The ref is fine. Any replacement must be comprehensive as different sources are never directly comparable, so it's far less misleading to give a set of figures from one source, of whatever date, than to hunt after recency. Chiswick Chap (talk) 10:53, 11 March 2024 (UTC)

Choanozoa, super-class between Filozoa and Animalia missing from info box
The class Choanozoa, which would fall between Filozoa and Animalia is not mentioned in this article's info box in the classification section, but is mentioned in other parts of the article, as well as being named as a subclass in the Filozoa article. Is there a reason for this? — Preceding unsigned comment added by Gonb (talk • contribs) 02:28, 20 May 2024 (UTC)


 * The taxobox gives a brief summary at some preset level of detail, naming just a few major clades like nested Russian dolls. There are nearly always more subdolls, as it were, invisible in between the visible ones. Chiswick Chap (talk) 03:12, 20 May 2024 (UTC)
 * I've changed the parent taxon for animals to Choanozoa, but unranked. It's unusual for taxoboxes not to show the immediate parent. I assume the reason is that the Choanozoa introduced by Cavalier-Smith was paraphyletic. Now it has been recircumscribed for the clade containing animals and choanoflagellates, it seems appropriate to include it. The Adl et al (2019) classification uses Choanomonada but this doesn't seem to be used widely [Correction: This is wrong. Choanomonada is their taxon for choanoflagelletes.]. —  Jts1882 &#124; talk 08:10, 20 May 2024 (UTC)
 * Good work! Many thanks. Chiswick Chap (talk) 08:17, 20 May 2024 (UTC)
 * I've corrected my comment on Adl et al (2019). They support the redefinition of Choanozoa as animals + choanoflgellates, attributing it to Brunet & King (2017) It was also used by Tikhonenkov et al (2020), which suggests the new usage has caught on. —  Jts1882 &#124; talk 09:33, 20 May 2024 (UTC)