Talk:Species

Definition

The definition I learned in high school (I know, I've set myself up to be wrong already) was: two animals are the same species if they can produce fertile offspring. Was that wrong/has it changed?--BlackGriffen (1) That definition can only apply to sexually reproducing species (how do you determine whether or not two bacteria, each of which can reproduce alone by splitting, can "interbreed"?) (2) Even among higher species, the lines aren't that sharp. There are severals "sets" of species, such as arctic seabirds, where species A can and does interbreed with B, and B with C, and C with D...but A cannot interbreed with D. So where do you draw that line? --LDC

Another problem with the definition is that there are well-accepted 'species' that can produce fertile offspring, but generally do not in nature. For instance grizzlies and polar bears breed successfully in zoos. Conversely there are animals which we accept as the same species even though they obviously cannot interbreed. For instance no matter how much a Great Dane and Pekinese may want otherwise, physical mechanics will be a problem. Yet both are dogs. --BJT

The last example brings to mind the great song by Australian folk singer Eric Bogle; it is the tragic tale of "little Gomez" a chihuahua of great might and courage. He became enamoured of a lady St. Bernard. When our hero tried to consumate his love, she sat down and tragically terminated his efforts. :-) Eclecticology

And what about post menopausal women? Are they a different species from humans because they can't reproduce successfully? 23:41, 5 April 2006 (UTC)

I think it would clarify things to introduce a section outlining the three common ways in which "species" is used today. Perhaps something like:

• Taxanomic. Species are classified, more or less arbitrarily, according to readily observable features, such as number of teeth, leaf shape, colour of feathers, and so on. This is the most common usage in everyday life, is convenient for the production of field guides, but often sheds little light on the underlying genetic isues and can be quite misleading.
• Biological. A species is distinct from another species if the union of the two cannot produce viable offspring. Has a satisfying logic on first inspection and is very useful for practical work with plant and animal breeding, but riddled with inconsistencies [as pointed out by LDC & BJT above]: many particular seperate taxanomic species can interbreed freely but seldom do in the wild, and the ability of any two seperate species to interbreed can be highly variable: some horse-donkey unions, for example, produce healthy, fertile mules. An arbitrary dividing line must sometimes be drawn to define a particular species.
• Evolutionary. Species is defined by relatedness of DNA sequences. More closely represents the web of relationships between different lifeforms, but this deeper level of abstraction moves the whole concept of species a long way away from its commonsense meaning.

Each of these three ways of defining a species is useful, each has its weaknesses, and the continuing use of all three helps highlight the underlying fact that the natural world consists of humps and subtle gradients which the straight lines and boxes of categorisation schemes can only render imperfectly.

Errr .... that last bit is a bit flowery, but you get the idea. I'm reluctant to go chopping up an article that is coherent and reads well as it stands, but at present one must read between the lines to understand that 'species' is as variable and as slippery a concept as it is. Putting some of the more common current definitions into dot point form would help, I think. Tannin

These are definitely contrasts that should be made. And please don't worry about chopping up the article. I think the article needs massive reconstruction anyway. Most of the history of taxonomy stuff probably belongs in another article, as does the not insignificant summary of how evolution is supposed to work. --Ryguasu 20:58 Jan 31, 2003 (UTC)

Is it even possible to provide a scientifically valid way of determining why animal A and animal B are of different species? It seems to me the different methodologies are insufficient for all types of life, and consequently the only way we can tell a species is different is by seeing a species that either is human or isn't (ie we can tell that another animal is human because we ourselves are human). However that method is hardly scientific. Piepants 01:56, 14 April 2006 (UTC)Piepants

The thing is, species are fundamentally statistical phenomena. Differences between species are relative, not absolute, and the term "species" is meaningful only in relation to something else. So I think it is not surprising that there is no single fully operationalized definition of "species." Slrubenstein | Talk 16:59, 14 April 2006 (UTC)

Obviously this means that the methodology for attributing a lifeform to a genus or etc isn't scientific (or can't be scientific) -- what does this mean (in terms of consequences)? Piepants 17:54, 6 June 2006 (UTC)piepants

If you are referring to my comment above, well, what I wrote is based on scientific research and reflects the views of scientists so it certainly is scientific. If you think it is not, then your definition of "scientific" may be wrong. Slrubenstein | Talk 13:50, 7 June 2006 (UTC)

That certainly is possible. I believe when I use the term "scientific" I mean that there are specific measurable concepts that we can adopt in other studies. For example I could argue that all of a certain group of dogs are of the same species because they share the same family tree. Obviously this doesn't apply to all lifeform. Or I could use 'can reproduce sexually', which obviously has similar problems. Perhaps these are poor examples; I am not a student of science. Piepants 21:13, 7 June 2006 (UTC)Piepants

There are roughly 25 definitions of species in the current literature. I have a document that lists them all (based on Mayden), gives citations, and I would be happy to offer it for someone to put into this article. It is an older version appendix to a book on species concepts under review now.

I find this article confused and incomplete, and relies on some questionable interpretations of the history of species concepts made by biologists themselves (mostly Mayr and Simpson). While it may represent the "textbook" view popular in the field, it is false. People did not think species had essences prior to Darwin. In fact species essentialism postdates the Origin by 30 years. Aristotle was neither a fixist (which began with John Ray) nor a transmutationist (which began with Pierre Maupertuis). Nor do types and "typological thinking" appear to involve essences, and the use of morphological "definitions" doesn't mean that the species concepts used by the taxonomists (including Darwin!) were essentialists. John Wilkins 11:27, 20 September 2006 (UTC)

• Claridge in the first chapter of the book he edited Species the unit of biodiversity defines species as a unit of taxonomy below which cladistic analysis doesnt make sense. That is a more practical way of defining species considering all life forms including viruses. Although this may sound a bit complicated to a first time reader, this is more accurate and with proper linking to other articles, this would be the best way to difine the species. Thanks. Wiki Sanjay ^\talk 15:24, 6 May 2007 (UTC)

That won't work either, because there are no set ranks in cladistic analysis - you can have haplotype groups or population-level cladistic analyses. In order to give a phylogenetic account of species, you have to appeal to non-phylogenetic criteria. John Wilkins 00:20, 14 November 2007 (UTC)

I'm not going to argue with the above, and just say how I would like to see this article arranged. I'd love to see an article Definitions of species, with the 25 definitions John Wilkins mentioned above, and have it summarized in this article. The introduction to species should start with a textbook definition, with some hint as to the variety of other definitions (which I think it does reasonably well already). Likewise, the history of the changing meanings should stay in Species problem (or perhaps narrowing the article to just the history of the term, which it is already really). So basically three articles, with room for a forth:

• Species
  • Definitions of species (a list)
  • Species problem (historical development)
  • Numbers of species (could possibly be expanded into an article?)

And it's a lot of work, even just to get all the stuff that needs to be moved into "Species problem" moved there. So I'll stop. —Pengo 06:12, 14 November 2007 (UTC)

I could rework an article I published in Reports of the NCSE for the definitions piece, and I could do a historical piece as well (the "species problem" arose in 1904 or a bit before, prior to that it was the "species question" - i.e., the origins of species). But not right now. John Wilkins 00:20, 15 November 2007 (UTC)

You can't proove a negative! Further all identifications, save the original one, are matters of opinion.Osborne (talk) 18:34, 22 May 2008 (UTC)

Metaphysics

I'm removing the following bit of metaphysics:

It is unclear whether the category "species" exists "out there in the world", or if its existence is entirely dependent on our human classification systems. Answers to this question may hinge on one's understanding of epistemology as much as of biology.

While this is a valid point, it has nothing to do with species in particular. You can ask the same questions about just about any scientific concept, if not just about every concept whatsoever. The only reason this should stay is if it ties in to a larger argument or controversy about species. --Ryguasu 20:58 Jan 31, 2003 (UTC)

Yes, and I didn't like the phrasing. But there is another similar but I think more important point: prior to Darwin many naturalists did believe that "species" were real things; Darwin's major accomplishment was to redefine them as statistical phenomena. This accomplishment is bound to Darwin's rejection of intentionality, and these two elements of his thinking are where the conflict between his followers and "creationism" is crystal clear. I believe the article makes this clear, but I guess whoever wrote this short paragraph was unsatisfied. Perhaps there is a point here that really should be stated more emphatically? Slrubenstein

Even now most naturalists believe that species are real things - I'm aware of a few species deniers (wrongly called "species nominalists"), but nearly all are species realists. Including Darwin.John Wilkins 11:29, 20 September 2006 (UTC)

I think the metaphysical problem is more one of clear definitions. "Species" is a fuzzy label (each creature's DNA being unique* though sharing common characteristica through common descent) and the conclusion is merely that it's ONLY a label and not something physical. I actually fail to see how it can be more than a label myself, especially after reading works by Richard Dawkins and his ilk.

Of course there are common characteristics shared by various individuals and of course the reproduction of such characteristics allows for easy labelling. Dogs look fundamentally different from, say, snakes, for example. In this case it's clear they require different labels. But the transitions from one species into the next are fuzzy, not clear.

If you follow human evolution back to the first living organism, you will have a hard time making clear cuts where transitions from one species into the next occur. That's the problem with an analogue system and digital labels.

Conceptually speaking, a species is more of an idea of one unique creature, the prototype for its species. That creature mustn't necessarily exist, and probably doesn't (just like the "average human" doesn't exist). Other individuals are then categorised depending on which prototype they resemble the most.

I can't comprehend how the wording "real thing" fits in here. The prototypes are not real, in that they don't physically exist, but the idea of them (an abstraction of a set of creatures with similar features) very much is. I don't think an article on species is the right place to question the definition of reality of non-physical things, either.

If you follow the gene-based perspective of Dawkins, of course all organisms become irrelevant and thinking of a species or group of creatures acting as an individual (e.g. "mankind" being an actor, not only metaphorically but practically) feels completely misguided when talking about the greater scheme of things and evolution at large.

I can see a conflict between the gene or individual based approach and the species super-organism based approach (the latter of which was probably the pre-Darwinist consense referred to above), but the labels alone are hardly disputable on metaphysical grounds.

The super-organism vs. inidividual organism (or even sub-organism, if you think of the genes alone) conflict however is very present, as there are (still) people adhering to the former, just as there are still people misunderstanding the scientific concept of a "theory". — Ashmodai ^{(talk · contribs)} 14:28, 23 September 2006 (UTC)

You are presenting one view- the species denier view I mentioned. But in an encyclopedia article one view should not be put to the detriment of the other views out there. I believe, from having spent a considerable time reading the literature, that most naturalists do think species are real things. Yes, there is a tradition (mostly in the Haldane school) of thinking that species are not real and are just conventions - John Maynard Smith said this in his little Evolution book, and also tome directly. But that view is hardly the widespread view of field taxonomists or even geneticists, as witness the Templeton cohesion concept and the Mallet genotypic cluster concept of recent years.John Wilkins 01:33, 29 September 2006 (UTC)

Actually you should have left that part in. See that is one of the main debates in biology today. I'm a Zoologist and one of the main debates is whether or not species actually exist. This debate can be traced back even to Darwin, who didn't actually agree with the concept of a species. Basically one arguement on one side of the debate is that we need species because we like an organised world, that is to say we need to classification of species because it helps us in research and reference (imagine saying you did molecular work on some animal, it's meaningless unless everyone know what animal that was). The other side of the debate is where the "metaphysics" comes in to play, and is completely valid as any other arguement. The question is this, how can you define a species when the "species" as we know them are just simple ever changing points in time and space? The key part to that is ever changing. We know that evolution can occur rapidly or extremely slowly, the point is though that evolution is constantly occuring within a population. There is another key point, evolution occurs on a population not the individual, matural selection is on the individual. So now the question becomes this: If a population of individuals, considered to be a "species," is ever changing and evolution always occuring, and that within that population there is variation between individuals, then how can we classify that one group into a single species? So overall, what you deleted is a completely valid arguement, and one that is still discussed within the biological community. That and, as I have explained, it is not so much metaphysical, but is actually based on processes that we know to be occuring as we speak, and evidence that is available in nature. MrRipperKing (talk) 01:53, 19 April 2010 (UTC)

Mr. Ripper King makes an important point. Darwin certainly did not believe that species are real in the sense that Linneaus did, or that many people today do. It is an important debate among naturalists and that is why it needs to be introduced, somehow. Slrubenstein | Talk 12:28, 19 April 2010 (UTC)

Copied from talk pages

Copied from discussion on talk pages between Alan Peakall and Slrubenstein

Hello SLR, If you feel like a change from talk on Israel/Palestine, I would value your thoughts on the coverage in Wikipedia of the word subspecies. A search shows that it is widely used in articles relating to particular animals, but a search on the article species shows no attempt being made to define it there. To ask a specific question, is it, in your view, correct to say that the majority scientific opinion captured in race, that human races have no objective existence, is equivalent to a statement that the species homo sapiens has no subspecies? -- Alan Peakall 13:10 Feb 18, 2003 (UTC)

Hi. I don't know enough about how zoologists or botanists uses the term "subspecies" -- is it the same as "variety?" Is a "subspecies" of a particular animal the same as a "population?" Offhand I would guess that what physical anthropologists call "populations" of humans may correspond to what zooligists call "subspecies" of an animal. I think the real problem is not the gulf between scientists who study humans and scientists who study other animals, but the gulf between scientists and laypeople. Scientists see "species" (and necessarily "subspecies") as statistical phenomena whereas many laypeople see species (and race) as fixed things. Slrubenstein

Several comments here:

1. Subspecies and variety are different things. The short version is, zoologists recognize subspecies as the only nomenclatural rank below species. Botanists, on the other hand, recognize three ranks below species: subspecies, then variety, then form. "Form" is rarely used anymore. Typically "variety" is used for more obscure and intergrading intraspecific taxa which nonetheless seem distinct enough to warrant naming, and "subspecies" is used for more distinct and discrete intraspecific taxa that don't seem distinct enough to warrant species status (because there is some minor intergrading, the morphological differences are difficult to observe, etc.). Sometimes botanists will recognize a variety of a subspecies of a species, but more often only one rank of intraspecific taxon is given for a species.

2. In botany and zoology (though I don't know anthropology) populations are simply local groups of interbreeding individuals and "population" doesn't imply any differentiation from other populations, whereas "subspecies" does.

3. The scientists who see species as statistical phenomena are definitely in the minority, at least among botanists and zoologists. The view of species as statistical phenomena was only explicitly developed, that I know of, by pheneticists, who are few and far between these days...

4. There seems to be an increasing tendency in some realms of zoology (herpetology is what I'm most familiar with in this regard) to reject the subspecies rank categorically. Researchers with this viewpoint will often publish works in which they regard any non-constant differentiation not worth naming, and any constant variation worthy of species rank. I don't buy it, myself.

Paalexan 03:30, 17 November 2005 (UTC)

Who is this masked man? Please consider adding this to the article—well maybe not the bit about herpetologists. ;^) It sounds like you could clarify several important points. - Marshman 04:24, 17 November 2005 (UTC)

I'll move this to your talk page - Marshman

Subspecies

I am not confident of my understanding of the status of the word subspecies in technical discussion either, but as the parent article points to race, I believe that it should at least discuss the concept. It seems to me that there are these possibilities: 1) the concept of subspecies is in general no more useful than race is for homo sapiens and therefore is deprecated in technical discourse, 2) the concept of subspecies is meaningful for some species, but, at least since the extinction of homo neanderthalensis, not for homo sapiens, 3) the possibility that you suggest, 4) that those who defend the use of the word race in a biological sense mean something different from a technically accepted meaning accorded to the word subspecies. -- Alan Peakall 18:53 Feb 19, 2003 (UTC)

One of my professors, who in part studies different species' perceptual systems, claims that what gets called a new species and what gets called a subspecies is often more historical accident than principled distinction. Perhaps this is similar to the unprincipled way in which certain scientific results end up being called "laws", others "theories", etc.. (I know many people insist these words have well-defined technical meanings, but whether or not people pay any attention to those meanings in deciding which label to use is another story.) --Ryguasu 20:51 Feb 19, 2003 (UTC)

You are making a non-argument there. The terms are well defined, but unfortunately, the common definition of "theory" is now in conflict with the scientific definition, leading to no end of debates about just what a person really means (and scientists are increasingly inconsistent in their use of the term; a real mess) - Marshman 04:27, 17 November 2005 (UTC)

As an armchair paleontologist I think Ryguasu's professor was making a valid point. Researchers who name a species get their names added in parentheses beside references to these species in scientific publications, which increases the researchers' prestige and career prospects. In 19th century dinosaur hunting Othniel Charles Marsh and Edward Drinker Cope engaged in a totally blatant race to name the most species of fossil dinosaurs and, since scientists are only human, I'm sure similar things happen to-day but more discreetly.Philcha 13:37, 14 March 2007 (UTC)

Tidy up needed

This article has grown into a bit of a mess. It starts well with a discussion of the different possible definition of species, but there's a ragbag of stuff at the end. It needs a thorough sort out - I'll get to it when I have time, but...

seglea 16:33, 9 Dec 2003 (UTC)

Might I suggest it be added that the definition in the Endangered Species Act which includes sub-species and "and any distinct population segment of any species or vertebrate fish or wildlife which interbreeds when mature." This is misleading and renders the question highly political.

Comment in edit summary box

Added this comment from 172.192.160.124, which was included in an edit summary box: --Lexor|Talk 01:14, 16 May 2004 (UTC)

I have not edited, but note the ambiguity of "ancestor" in "A phylogenetic or evolutionary or Darwinian species is a group of organisms that shares a common ancestor [species? individual?]."

Aristotle's sense of the word species

Aristotle, in his Categoriae, uses "genus" and "species" in a nonbiological sense more closely related to the terms generic and specific. Perhaps mention of this would be appropriate, if only for its etymological ramifications: the meaning of the word "species" grew more specific as time went on. - Jrn 16:29, 11 Oct 2004 (UTC)

It's definitely worth mentioning Aristotle, he came up with the original (very interesting and totally wrong) species concept, and started the work that Linnaeus picked up and improved. He also noticed the difference between individuals and between species, deeming them accidental and essential, a concept that stuck until Darwin, which is an interesting historical note. I've begun adding this. --Joe D 19:35, 11 Oct 2004 (UTC)

Aristotle and his student Theophrastus had a definition of "species" - in logic. Their logical definition is not the same thing as the uses of genos and eidos in their natural histories. Don't forget that these terms - genos means tribe or family, and eidos means form or appearance, and is commonly used to mean "kind" - are just vernacular terms too. And Linnaeus' use of the terms from traditional logic are not, in themselves, logical terms, and they do not involve the same motivations as the Categories, Metaphysics or Posterior Analytics. John Wilkins 11:34, 20 September 2006 (UTC)

Biological Species Concept & realms of biology, etc.

Please pardon if I am posting this in the wrong place; I am not familiar with Wiki protocol, but I note a problem that should be specifically addressed. Under "Biologists' working definition" this statement uses the word "class" in a way that will confuse some biology students because they know the term as the taxonomic rank between phylum and order: "Some biologists may view species as statistical phenomena, as opposed to the traditional idea, with a species seen as a class of organisms." — Preceding unsigned comment added by 74.67.225.15 (talk) 13:20, 21 July 2011 (UTC)

Since the entry for species primarily treats the BSC, a few things are worth mentioning about it:

1. It is used heavily mostly in ornithology and mammalogy. I don't know fish or arthropods, but the BSC is very problematic in herps (species that are reproductively isolated in the wild but completely interfertile under artificial conditions are quite common). In botany the BSC has never played a significant role. As a result, the traditional approach followed here, of treating the BSC as "the standard species concept", seems to me a bit misleading.

2. Even in groups where taxonomists adhere to the BSC, most species are actually described and defined simply by using the morphological species concept. In order to explicitly apply the BSC, you need to do a bunch of cross-breeding experiments, and there simply isn't time or funding to do that for more than 0.01% at most (a very optimistic "most"!) of the taxa on earth. The result is that even in the 5% (or however much exactly) of taxa where the BSC is applicable in a useful fashion, biologists apply it directly on very rare occasions...

3. "Gene flow" and "reproductive isolation" are used interchangably in the entry, though they are very distinct phenomena, and this distinction is a severe problem for the BSC. For instance, in the sentence:

"Without reproductive isolation, population differences cannot develop, and given reproductive isolation, gene flow between the populations cannot merge the differences."

The first half is only true in terms of gene flow, not in terms of reproductive isolation (as that term is typically used in the BSC).

4. Allopatric populations and defining "reproductive isolation"... this is a recurrent problem for BSC advocates. In his original definitions, Mayr did not include "potential interbreeding", which meant that even geographic isolation was sufficient to qualify as "reproductive isolation", and all allopatric populations become new species regardless of any other considerations. In later definitions, Mayr added the "potential" part to allow allopatric populations to be treated comprehensibly, but defining the word "potential" is extremely problematic. What you'd want it to mean is that the species, if they occurred together naturally, wouldn't interbreed. However, that's untestable, so falls into the realm of simple speculation. So what BSC advocates usually do is say that "reproductive isolation" means that the species either won't mate or will produce infertile/inviable offspring if they do. This has its own problems (of which "3" is in some sense a subset) in that hybrid infertility is only one of many reproductive isolating mechanisms in the wild, and most of the other mechanisms (including behavioral ones) tend to break down under artificial conditions.

It's also worth mentioning that under the heading "phylogenetic or evolutionary or Darwinian species" is actually subsumed a variety of different species concepts which are mutually incompatible. Under "phylogenetic species concept" in botany there is both the PSC of Nixon & Wheeler and then several slightly different things that are perhaps better called "genealogical species concepts". PSC in zoology usually only refers to the "genealogical species concepts", and not the PSC of Nixon & Wheeler (just to confuse things; the PSC of Nixon & Wheeler might be called a "synapomorphic" or "phenetic" species concept by zoologists). The "evolutionary species concept" (of, e.g., Frost & Hillis) is widely cited in herpetology but rather vague; species are defined as "populations or groups of populations that are on independent evolutionary trajectories" but what exactly an "evolutionary trajectory" is, or how you're supposed to recognize one when you see it, is never made clear. "Darwinian species" is a term I haven't heard...

Dogs and cats

It often corresponds to what lay people treat as the different basic kinds of organism - dogs are one species, cats another. Does this sound like it's saying that the two are members of the same genus? - 203.34.41.43 01:04, 22 December 2005 (UTC)

No it does not. Do not make the common mistake of confusing "species" as used here with the term "species" refering to the second or modifying term in "Genus species" (more correctly the specific epithet). A species of animal (or plant) is not the latter: the dog species is Canis lupus (not lupus) and the cat species is Felis silvestris (not silvestris); thus the same genus is not implied at all - Marshman 01:53, 22 December 2005 (UTC)

On a subject that is only tangentially related, I read somewhere that "what lay people treat as the different basic kinds of organism" corresponds more nearly to genus than species (with the possible exception of domesticated animals). It's just that locally one is unlikely to encounter more than one species of the same genus. Thus each "primitive tribe" (traditional society) knows only one representative of each genus that it encounters.

As for the source, it might have been Gould, Dawkins, or Dennett. Or maybe somerthing on linguistics such as Mallory's In Search of the Indo-Europeans. Zyxwv99 (talk) 13:49, 19 March 2012 (UTC)

Wikipedia:Science collaboration of the week

Chronospecies is a current candidate on Wikipedia:Science collaboration of the week. If you would like to see this article improved vote for it here. --Fenice 17:48, 4 January 2006 (UTC)

elephants

Perhaps it would be helpful for the lay person, if anyone with sufficient knowledge would be pleased to explain the classification of the African elephant species (plural) in terms of this article?

Mitosis and Meiosis in microspecies

A few minutes ago, the article suggested that microspecies do neither meiosis or mitosis. This, I think, is foolishness, as all organisms do mitosis. I have changed it, but if some expert of microspecies disagrees, go ahead and change it back. --Pjvpjv 14:26, 13 July 2006 (UTC)

Apparently someone reverted that change. I independently noticed this just now (03:23, 14 Sep 2006 (UTC)) and am making the same correction again as Pjv's change was correct. The "see also" in the section refers to the same phenomenon and says nothing about lack of mitosis either. If someone is absolutely positive that certain organisms reproduce using neither meiosis nor mitosis, they should either say so in this discussion or add a citation before changing the line back.

Protists

I noticed your quick example guide to the number of species in each major group left out protists.

There are thought to be approximately 200,000 species of protists, and about 120,000 are named. See papers by Corliss 1982.

Since 'Protists' is a paraphyletic group, here is an approximate breakdown by clade:

Foraminifera 37,500 Diatoms 25-100,000 Green algae 10,000 Ciliates 7,500 Actinopod amoebae 7,000 Red Algae 6,000 Sporozoa 4,800 Stramenopiles 4,500 Dinoflagellates 4,200 Rhizopod amoebae 2,500 Metamonads 2,200 Unspecified flagellates 2,000 Euglenoids 1,600 Haptomonads 1,500 Chytrids 900 Myxozoa 875 Microsporidia 800 Slime molds 550 Pelobionts 280 Cryptomonads 200 Choanoflagellates 140 Plasmodiophorids 36 Haplosporidia 30 Acrasids 26

Nutrea... a Texas thing?

Howdy Y'all I am a native Texan and have grown up fishing in creeks and rivers. We have an animal called a nutrea that I don't know much about and would like to gain more information. I was unable to find any articles about nutreas on the cite, so I'm wondering if any other areas have them. Some people call them river rats, and they remind me of beavers, only creepier. It would be great to have any information. Thanks Y'all!

Hey bud - try nutria. Graft 05:02, 8 September 2006 (UTC)

I've created a redirect page for it. These are always useful for misspellings. Richard001 07:21, 3 May 2007 (UTC)

species problem

This article alluded to disagreements and uncertainty over defining species. In fact this is a huge issue. I just posted a new article on the species problem. I also stuck in a couple links to it in this article, and fixed Mayr's last definition of species Karebh 02:52, 2 February 2007 (UTC)

Good move, Karebh. I'm currently editing the Species article to make the structure more logical and get the main items at least referred to. Then I think we should work together to decide what should be in Species and what should be in Species problem - I agree that the problems take up a huge amount of space in Species (partly my fault :-). I suspect the main issue will be how to tie in the various "limited" / "special purpose" concepts of species without going overboard on the species problem in the Species article. Look forward to discussing this with you soon.Philcha 13:48, 14 March 2007 (UTC)

In this section, the statement "In a few cases it may be physically impossible for animals that are members of the same species to mate. However, these are cases in which human intervention has caused gross morphological changes, and are therefore excluded by the biological species concept" does not appear to be supported by the various definitions listed, nor by any that I have encountered as a biologist. No mention is made of "no artificial speciation" - or, rather, in the case referred to, no artificial creation of a (non-geographic) ring species (since intermediate breeds of dogs, for instance, can still interbreed, even if size differences prevent successful breeding between, say, Great Danes and Chihuahuas). Admittedly, such differences (at least with larger females and smaller males) can be overcome with artificial insemination; how to classify this is uncertain. Allens (talk) 14:50, 18 October 2011 (UTC)

I am aware, BTW, of the "natural populations" part of Mayr's definition; however, as far as I am aware, this refers to the members of the populations not being currently "artificially" separated (e.g., a breeding colony in a zoo is not considered a separate species, despite its members not being able to breed with organisms outside the zoo) and the breeding taking place not being artificially assisted. Even if one supposes this to cover the case of human-made species, "the biological species concept" still incorrectly assumes the existence of a single biological definition of species. Allens (talk) 14:59, 18 October 2011 (UTC)

Section "The isolation species concept in more detail"

This section is too long compared with the rest of the article and expands on content earlier in the article. I suggest "The isolation species concept in more detail" should be moved to a separate article and the Species article should link to it. As far as I can see from the "history" page, section "The isolation species concept in more detail" was added by Artat. It would be nice if Artat could create the new article, so that the history pages give him / her credit for the content.Philcha 14:05, 14 March 2007 (UTC)

I agree. There is a page for reproductive isolation that could be improved and expanded. It would take a lot of this out of the article, and allow the Species article to keep its focus. Oeft 13:46, 23 April 2007 (UTC)

Past interbreedability

The ancestors of humans and chimpanzees interbred until 4 million years ago: NOT one million years ago as the text says. The pre-humans living one million years ago are called Homo erectus (“upright man”). Except for a distinctive head they looked very similar to us. They had stone tools, hunted big game, and it was only a matter of time before they tamed fire. To claim that these interbred with chimps and had fertile offspring is simply not credible!

2007-03-27 Lena Synnerholm, Märsta, Sweden. —The preceding unsigned comment was added by 81.233.151.160 (talk) 12:31, 27 March 2007 (UTC).

Yes, I agree. Someone should fix the article. It probably currently reflects some media-sensationalised study or other or has been vandalised. Please edit the text to reflect this. {{sofixit}} follows: Thank you for your suggestion! When you feel an article needs improvement, please feel free to make those changes. Wikipedia is a wiki, so anyone can edit almost any article by simply following the Edit this page link at the top. You don't even need to log in (although there are many reasons why you might want to). The Wikipedia community encourages you to be bold in updating pages. Don't worry too much about making honest mistakes — they're likely to be found and corrected quickly. If you're not sure how editing works, check out how to edit a page, or use the sandbox to try out your editing skills. New contributors are always welcome. —Pengo 12:52, 27 March 2007 (UTC)

I do not believe that the article claims that the ancestors of humans and chimps interpred a million years ago. Slrubenstein | Talk 14:29, 27 March 2007 (UTC)

It is written in the second paragraph following the headline “Difficulties in defining ‘species’ for extinct organisms”. However, I am not sure about the exact time of interbreeding. It might had stopped 4.2 million years ago because fertile offspring was no longer possible.

2007-03-27 Lena Synnerholm, Märsta, Sweden.

The sentence(s) to which you refer do not say that the ancestors of humans and chimps interbred until 1 million years ago. Slrubenstein | Talk 15:53, 27 March 2007 (UTC)

Sorry, I read it carelessly!

2007-03-28 Lena Synnerholm, Märsta, Sweden.

Prokaryotic/bacterial species

I was wondering that prokaryotic/bacterial species is not mentioned in this article. I do realise that prokaryotes species concept is rather too vague at this moment but there is indeed a practical one going on at this time. It cant be merely considered as a phylospecies concept since it uses a polyphasic approach including morpho, chemo and molecular taxonomies. Wondering if a mention of the polyphasic approach in this article which links to a seperate entry on bacterial species would be a good idea. Wikiality 10:08, 6 May 2007 (UTC)

I'm looking for opinions onto have a seperate wiki entry on Prokaryotic Species Concept. This will include definition, bacterial systematics pradigm, genomic species, phylospecies, chemospecies, morphospecies and polyphasic taxonomic approach of species. Can I have some feedback if possible on this please? Thanks! ώЇЌĩ Ѕαи Яоzε ^†αLҝ 11:19, 5 June 2007 (UTC)

Species

• • • - A group of "organisms" capable of interbreeding and producing fertile offspring of both genders, and separated from other such groups with which interbreeding does not (normally) happen.

So...."NORMALLY" ??? What are the names of "mammal species" that CAN interbreed ? silkythreads@gmail.com —Preceding unsigned comment added by 98.204.130.47 (talk) 16:18, 26 December 2009 (UTC)

They are called hybrids. Grizzly–polar bear hybrid, Liger, and Wholphin are some examples. —Pengo 18:29, 27 May 2010 (UTC)

Wolves and coyotes (see Coywolf). Zyxwv99 (talk) 13:33, 19 March 2012 (UTC)

Radically accelerated evolution

I removed the section about "evolution is radically accelerated", There are so many errors in this paragraph, I don't think they can be fixed. 203.143.238.107 03:57, 15 May 2007 (UTC)

"In recent years we have witnessed the drastic reduction in the size of breeding populations and the geographical range of many large mammals. In earlier times it was assumed that every species existed in at least a few thousand living individuals, except very rare relic, isolated groups. In the present, many well know mammal and bird species are so stressed by habitat loss, and other effects of the modern world, that only a very few breeding males may contribute the genetic material to a small number of breeding females. In these highly stressed conditions, the likelihood of change is very much greater. Mammals may become smaller, have darker fur, more stripes, more cautious behavior, even over time learn to co-exist with the human world. Very likely, evolution is radically accelerated, and we are only beginning to notice it. It is possible that this severe stress is essential to the creation of new species, and may have been a prime factor throughout biological history, from other population reducing influences."

I agree with this removal of this text. There is a fatally flawed understanding of evolutionary processes shown in it. —Pengo 14:30, 15 May 2007 (UTC)

Article length and species problem

Perhaps 70% of this article overlaps with species problem. This article is also currently 44KB, which is longer than the ~30KB normally recommended. I have tagged several sections dealing with the question of how to define a species for merger with the other article. That will move out a considerable amount of material; a brief summary should be left behind here. Another problem is that both articles have history sections. The history of the concept of "species" is pretty much the same thing as the history of the definition of "species". Given the amount of material, it might be best to spawn a third article dedicated to this topic. -- Beland 20:21, 18 May 2007 (UTC)

I wish anyone luck who attempts to clean it up. I've changed your tags a little. Instead of simply splitting the article into "species" and "species problem" I've proposed to make "Species" a summary-style article, with species problem as one of the articles that is summarised. (This is what seems to be have happened already, albeit badly). The split isn't that clean though. Obviously the history of the problem belongs in "species problem" but does the list of species definitions belong in "species", "species problem", or its own article ("Definitions of species") ?

I wonder if "Historical development of the species concept" would be a better article title than "Species problem"? —Pengo 05:00, 10 November 2007 (UTC)

Species inflation

I started to edit the section on species inflation contributed by User:BanyanTree : original, my edits. However on closer scrutiny the section (and the source article in the Economist) lacked any substantial claims. For example, there were no specific claims of "species inflation" except for the polar bear and brown bear, which have always been classified as a separate species (as far as i know anyway); and the counter example of the Jamaican raccoon which is somewhat meaningless because the situation would have been the same if it were found to be the same subspecies as found in Northern America. So I deleted the section entirely. That's not to say Wikipedia shouldn't have have anything on this perceived trend, but we should start with something more substantial than an editorial piece. Sorry to have to delete it, BanyanTree. —Pengo 04:49, 24 May 2007 (UTC)

"Species inflation" appears to be another term for "taxonomic inflation", which seems to be largely a result of the "splitting" described in this article. (List of academic articles, blog and commentary discussion on The Economist and Wall Street Journal articles) Taxonomic inflation certainly seems to be well-accepted enough for its own article, or maybe just an expansion of Lumpers and splitters. I'll let someone who knows this field figure out what needs to be written and in what structure. - BanyanTree 08:48, 24 May 2007 (UTC)

Yep sorry, I don't disagree that it deserves a place in Wikipedia, probably as its own article, it's just that the Economist article had such negligible substance as to have virtually no use to an encyclopedic article. —Pengo 09:13, 24 May 2007 (UTC). A spacific type of animal or plant.

Naming convention: abbreviation (contradiction?)

In the subsection "Abbreviation" of the section "Binomial convention for naming species," it is said that "In books and articles that use the Latin alphabet, genus and species names are usually printed in italics. If using "sp." and "spp.," these should not be italicized." However, earlier on, the section uses the term "Canis sp.," (note the italics) which appears to be in contradiction with the note on usage. Am I right that this should be changed, or is this a special case of some sort? Thanks. —Preceding unsigned comment added by 24.182.169.64 (talk) 03:02, 23 April 2008 (UTC)

I note that this was never answered or otherwise dealt with. The article meant that the terms "sp." or "spp." are not italicized, not that the genus name to which they are attached should not be italicized. I have clarified the article text. Peter coxhead (talk) 13:48, 19 March 2012 (UTC)

Numbers that don't make sense

"Total number of species (estimated): 2 - 100 millions (identified and unidentified), including: 5-10 million bacteria[11];"

The lowest number of bacteria cannot be bigger than the lowest number of species because the former is a subset of the later. Probably the number have been collated from different sources. Maybe the number of species did not include bacteria. Anyway the numbers as listed just don't make sense. —Preceding unsigned comment added by 82.67.232.89 (talk) 16:41, 24 March 2009 (UTC)

You're correct. Having a quick look at the sources I think the figure of 2 million excludes bacteria. --Michael C. Price ^talk 21:58, 24 March 2009 (UTC)

Undiscovered species

Already added this entry: At present, organisations as the Global Taxonomy Initiative, the European Distributed Institute of Taxonomy and the Census of Marine Life (the latter only for marine organisms) are trying to improve taxonomy and implement previously undiscovered species to the taxonomy system.

will add a (much needed) bar chart soon. KVDP (talk) 13:54, 28 October 2009 (UTC)

"Life support species"?

I have removed a paragraph that seems out of place, and has no citations; I include it here:

Life Support Species: Many species display distinct adaptations to environmental extreme, as they are able to grow and reproduce under such conditions as drought, desertification, flood, soil toxicity, soil sailinity among them a number already provide source of food, materials and energy to humans, livestock and other animals, are of considerable potential benefit to man. and these are known as Life support species. As such they mutually include keystone species since these hold the key to the integrity of landscapes which include both the diversity of living biota and the human communities. Both ecological and socio-economic species are Life support species.

First, this seems to be discussing an ecology/conservation concept used primarily by ethnobotanists, only marginally related to the topic of THIS article, which focuses on species as a taxonomic unit. As such, I question whether it belongs here at all. If it has only appeared in the context of plant ecology and conservation, and has no broader recognition within the scientific community, then perhaps the appropriate articles for it are those related to conservation biology, such as the article Keystone species.

Second, if other editors believe it should be retained (even if moved elsewhere), it needs to have its grammar cleaned up AND it absolutely must be accompanied with citations. Who first coined the term? Who, if anyone, has applied it outside of ethnobotany? How does it relate to concepts like keystone species, flagship species, indicator species, and other ecological concepts of a similar nature?

The bottom line: THIS article does not discuss concepts like keystone species, flagship species, etc. - and "life support species" seems to be precisely this sort of thing - best discussed elsewhere. Dyanega (talk) 17:10, 27 April 2010 (UTC)

Grammar

In English at least, "species" is the plural form. Why is the word used in the singular context? ... Regards, PeterEasthope (talk) 01:10, 11 May 2010 (UTC)

"Species" is both the singular and the plural. I don't know why it ended up that way, but it did. Could have come from Latin. -- Why Not A Duck 01:39, 11 May 2010 (UTC)

The word "specie" exists, but means something totally different and is not the singular of "species" as used in this article.96.54.32.44 (talk) 01:44, 14 December 2010 (UTC)

WTF happened to the intro?

Almost this entire article is now dedicated to the lawyering of definitions, with little focus on actually helping the reader understand what a species is. There is no longer any concrete examples of species, there is no mention of the relation between species and genus, there is no mention of bionomial names, and there is no attempt to give a short, easily-understod definition (to be expanded later), and there is far too much emphasis on the debate about definitions.

Yes, definition is important, but most of the time species boundaries are clear cut. And we already have an article dedicated to the species problem. This is an encyclopedia, and an article about species. It's not just an overly-long dictionary definition.

Here is a link to an older version of the article with an introduction covering the above (which I, and many others, worked on substantially). I can't find the exact point when it was replaced with a mere definition. —Pengo 10:02, 5 July 2010 (UTC)

OK, I had to revert the intro back. I hope I didn't take it back too far. —Pengo 10:18, 5 July 2010 (UTC)

I have no b=pfoblem with your edit, the version you reverted to is clear and useful. Still, th introduction should introduce the entire article. And much of this article is about the problems defining species (not because we do not know what a spcies is beut because species are ideas and not really things in the world the same way that a specific creature I am obseving or holding in my hand is real.

I wonder if you could draft a concise and easy-to-understand paragraph on the shift from the Linnean (ideal type) to the Darwinian (statistical artefact) view of "species" which is so important for modern biology, and fit it into the intro. Slrubenstein | Talk 14:56, 5 July 2010 (UTC)

Thanks for your feedback. Yes, that would be a good addition. I'm not sure I'm up to the task of writing it, but I'll have a look. —Pengo 16:59, 5 July 2010 (UTC)

Thanks ... I think if you could, it would pre-empt others who would edit it back into the confused set of reasons for why it is so hard to define species, by acknowledging the main issue (I am supposing) behind the various dits you in effect reverted by reverting back to an earlier version (Which I repeat I do not object to). Slrubenstein | Talk 09:23, 6 July 2010 (UTC)

Science Daily external links

A bit spammy/overly long no? Remove? Richard001 (talk) 07:14, 17 September 2010 (UTC)

Add prokaryotic known vs. predicted number of species

I am a PhD microbiology researcher, so I'm biased, but this article could use a few more values for the number of microbial species. There is no estimate for the number of prokaryotic (bacterial and archaeal) species that are identified (scientifically named and described species) in this article, only ESTIMATES of the total. Both and both known and estimated numbers are provided for eukaryotes. For prokaryotes, how the species in known (type culture, by 98% rRNA sequence, or estimated) is important.

Therefore, I would like to propose adding the following outline in the section on Number of Species, between the outline "Total number of species (estimated)" and the outline "Of the identified eukaryote species we have:".

Of the 6,000 to 170,000 identified prokaryotic species there are:

• 16,000 prokaryotic species "seen by science", based on the number of different 98% unique 16S_ribosomal_RNA sequences in databases as of 2004. This analysis was based on a total of 56,215 16S rRNA gene sequences, the total number of 16S rRNA gene sequences in 2010 was 1,483,016, almost 30 times as many.
• 6,728 bacteria Type_strains that are fully described, currently stored in culture collections, and with a sequenced 16S_ribosomal_RNA gene (as of 2008).
• 165,676 bacteria species with some genetic sequence known (of which 10,045 were in Microbiological_culture)), as of 2011
• 4,794 Archaea species with some genetic sequence known (of which 395 were in Microbiological_culture)), as of 2011

I think that the above addition would allow readers to compare the numbers of identified vs. estimated species in enough detail. This would mean deleting the "In 2007, they broke down as follows" sentence, since it does not apply to all that follows, and it is cited again when appropriate anyway.

Here is my reasoning for the above values:

This paper: The All-Species Living Tree project. Yarza et al. 20008 http://www.ncbi.nlm.nih.gov/pubmed/18692976 provides a lower-bound estimate of 6728, since the Type Species they are describing are a subset of named species, almost all of which have been grown in pure culture and are in collections (see article).

While the estimates of 5–10 million bacteria are still current, and probably better supported (as pointed out elsewhere, the species concept is even more difficult for these organisms) the paper listed below cites a range from 10^7 to 10^9 (10 to 1,000 million) for the estimated number of species on the planet.

There is also published estimates of 35,498 total species richness, based on the 16,000 species that have been "seen by science". This latter value is based on the number of different 16S_ribosomal_RNA or RRNA genes (also see Molecular_phylogenetics) that are 98% or more divergent as described in this paper: Status of the Microbial Census. Schloss and Handelsman. 2004 http://www.ncbi.nlm.nih.gov/pubmed/15590780 . However, the data they were basing their estimate on was much less than is in current databases, so I referenced release 10 to the RDP for a current number.

I've included values from the NCBI GenBank database's Taxonomy section since it is current, and the repository for all sequences. NCBI also has a taxonomic identifier for each sequence.

69.92.225.92 (talk) 01:18, 9 January 2011 (UTC)

Typological species vs. Morphological species

This is emphatically NOT intended as a starter for another interminable discussion of how to define "species", but an issue of whether terms derived from the literature are correctly described and referenced. In Species#Definitions of species there are paragraphs headed "Typological species" and "Morphological species", which aren't referenced. "Typological species" is a concept which seems to originate from Mayr (1963), although this is not cited in the article, where Mayr's views seem to be based on secondary sources (including ones which might well be regarded as hostile, such as de Queiroz – Mayr and de Queiroz have regularly disagreed in print over cladistic taxonomy). Mayr specifically says "The typological species concept, translated into practical taxonomy, is the morphologically defined species" (Mayr, 1963, p. 16; also quoted in Ruse (1969)). Hence there is no referenced justification for keeping these paragraphs separate, nor for attaching the term "morphospecies" only to the "Typological species" paragraph. I'm not going to make an edit to what is clearly a contentious topic without some prior opportunity for comment, but I would like to merge or otherwise connect these two and add some clearer references.

"phonetic"

The article says, "According to this concept, populations form the discrete phonetic clusters that we recognize as species..." Is "phonetic" a typo for "phenetic"? I'm not sure enough to change it. —JerryFriedman (Talk) 16:33, 6 June 2011 (UTC)

I'm sure it is (anyway "phonetic" can't possibly be right). I've changed it. The real problem is that every one of those species definitions needs an inline reference. Peter coxhead (talk) 03:50, 7 June 2011 (UTC)

I also added "citation needed" and a "who?". Referencing in this important article, which covers an area of biology often in dispute, needs to be much better. Peter coxhead (talk) 03:55, 7 June 2011 (UTC)

Fake precision

> 1,367,555 animals, including: [...] 1,000,000 insects

It makes it sound like 1,367,555 is a precise number, but it obviously isn't if it includes "something around a million insect species". — Preceding unsigned comment added by 86.176.98.25 (talk) 16:46, 18 July 2011 (UTC)

Yes, fake precision, but inherited from source. Would be a quagmire to "correct". -- cheers, Michael C. Price ^talk 17:41, 18 July 2011 (UTC)

I don't see why it's a "quagmire". A figure like 1,000,000, accurate to 1 significant figure at best, is being added to others which are much more accurate. When numbers are added, the accuracy of the total can never exceed the accuracy of the least accurate. So instead of reporting 1,367,555 animals, it should be reported as around 1,400,000 animals. WP:CALC allows editors to make their own calculations, so it doesn't matter that this figure isn't in a source. Peter coxhead (talk) 19:11, 18 July 2011 (UTC)

Extreme repetition

This page discusses the species problem (1) in the introduction (2) in the little head-section "Biologists' working definition", (3) under "Difficulty of defining "species" and identifying particular species", (4) under "Definitions of species" (these last two both point to "main article Species Problem". I'd like to take out all but one of these.

The section "Species as taxa" is about how species are named under the various codes of nomenclature, and that has already been covered above under "Placement within genera" so I'm going to start being bold by taking that one out.

This page needs trimming to less than half its current size. Nadiatalent (talk) 13:58, 10 December 2011 (UTC)

Biological Species Concept

There is a redirect here from Biological Species Concept, and it is linked from Ernst Mayr, but it is not dealt with as such on this page. I'm inclined to think that it would be best as a separate page ... Nadiatalent (talk) 18:21, 17 January 2012 (UTC)

A Remark regarding the concept: At the beginning of the article is said: "From a scientific point of view this can be regarded as a hypothesis that the species is more closely related to other species within its genus (if any) than to species of other genera." This is not a hypotheses, it is a fact, because of the definition: Creatures can be grouped within one genus, when they are related closely enough. If not so, they are from different genera. They are not related, because they are one genus - they are one genus because they are related. — Preceding unsigned comment added by 91.51.112.188 (talk) 16:56, 30 January 2012 (UTC)

Um... Actually they are one genus because they are hypothesized to be related, which is what the article tries to say (not, I agree, as clearly as possible). Evidence, such as genetic similarity, may support such a scientific hypothesis or may not. Peter coxhead (talk) 13:41, 19 March 2012 (UTC)