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"There are approximately 10 times more bacterial cells than human cells in the human body"

That doesn't make sense. What's the differnce between the two? The general public thinks of bacteria as seperate from the human body, and not a part of it. My brain is telling me there's more muscle, bone and organs than bacteria.

If it does make sense and I'm missing it, maybe it could be clarified.

It is by cell number not volume. Sad mouse 19:27, 20 January 2007 (UTC)

Yes, to clarify eukaryotic cells are around 100 times larger than prokaryotes. Now considering this is only diameter, their volume is going to be around 100^3, i.e. one million times smaller than ours, and their mass around the same figure. With this in mind, the mass of bacterial cells, assuming similar density to human cells, will be around 1 part per 100,000, which would translate to around 1 gram of bacteria or less per human being. It doesn't sound like much now, but when you consider that there are 100 trillion cells in the human body, there are quite a few bacteria in that gram or so. See Human flora for more on the subject. Richard001 20:47, 20 January 2007 (UTC)

I doubt your calculations. The article states that bacteria are 1/10 the size of eukariotic cells. That gives a volume ratio of 1/1000 not 1/100,000,000. See my comment below... - FrankH 22:13, 20 January 2007 (UTC)

I see. So it's on a "number of" basis rather than a mass basis. Bacteria are smaller than normal human cells. Thanks, it does make sense now.

I doubted this statement at first, but then thought along these lines:: The article also states that the size of the typical bacteria is about 1/10 the size of a typically eukariaotic cell. Taking this as a linear dimension means the volume of the bacterial cell is 1/1000th the volume of a eukariotic cell. Since our bodies are made of eukariotic cells, the statement that there are 10 times more bacterial cells than the human cells in a body means that the total volume of the bacterial cells is 1/100th the volume of all the human cells. Thus in a 200 lb man, the bacteria would weigh about 2 lbs (assuming the density of the bacterial cells and human cells are about the same). This does seem like a reasonable weight for all the bacteria in the gut and on the skin - at least to me. Does anyone else think saying something like this in the article would be helpful or not? My other question is, are there many bacteria in the body that are not in the gut or on the skin? I don't think so, but I don't know. Any experts? I understand that when there is an active bacterial disease, they can be in other tissues, so my question is about a healthy human... FrankH 20:55, 20 January 2007 (UTC)

I don't know for size, but here is an excerpt from Infection, The Uninvited Universe, 2006 on number: "Though we don't often notice it, every human is mostly bacteria. In an average human body...only about 10% of cells are what we call "human" cells. The rest--the vast majority, about 90%--are bacteria." To get a prospective on weight, it goes on to say "...and our feces, by dry weight, are 50%-60% bacteria."-- Elgringo18 01:34, 22 February 2007 (UTC)

These size calculations are kind of ridiculous, first of all 'cause cells (especially not the bacteroides and E. coli in our intestines) ain't spheres, and second of all the 1:100 linear size "rule" is an exaggeration. Think of it like this: when you poop, that's virtually all bacteria. Your food got turned into bacteria! Yikes! Hurray! Yeah, these buggers are small compared to yer typical eukaryotic cell, especially by volume. I don't believe the 1:1,000,000 rule, but I'd happily go with anything in the 1:500 to 1:30,000 range. I'm just pulling those numbers out of non-existent hats, by the way. There are many species of bacteria - including chlamydia and rickettsia - that are obligate intracellular pathogens. They have to live inside eukaryotic cells. So hundreds or thousands of them get packed inside of each infected cell. Cajolingwilhelm 02:50, 17 May 2007 (UTC)

Hi all. I have started to prepare a comprehensive rewrite of the entry Bacteria. I am a microbiologist so I have some some background for the job. If others are interested in collaboration on this task I would be open to that. Leave a message here or on my Talk page.

I propose the following table of contents:

1. Identification and Classification

2. Cell structure

3. Metabolism

4. Reproduction

5. Growth and culture

6. Movement

7. Bacteria and Human Health

8. Bacteria and the Environment

9. Industrial uses of Bacteria

10.See also

11.Sources

12.Further reading

I intend on keeping much of the current content but rearranging it and adding to it considerably. I have read all of the other comments on the page and am considering many of the suggestions.

-- Azaroonus 15:39, 9 August 2006 (UTC)

Hi Azaroonus. While the current article is deficient in places, a complete rewrite (which you suggest up top) probably isn't necessary. Your suggestion to use as much text as possible from the extant version is a good one and probably the best way to go (especially in terms of saving you effort). By all means alter the article structure if you've got a better layout for it. Something about the evolutionary history of bacteria would be good. Also, I presume the current "history" section will be squeezed into Human Health of something in your new plan? If you're planning on adding references, I'd advise checking out the best way to do this - there are several, but some good templates exist for adding stuff like journal entries. Cheers, -- Plumbago 15:50, 9 August 2006 (UTC)

Lets's call it a comprehensive rewrite then :-) Yes, it is best to keep the content that exists and at a first look I think that most of the current content should stay. Most of the topics that should be covered are covered, the major problem with the article is that it is disorganised and unclear.

Your comment about the history section: don't you think that the short history section that is currently in the article does belongs in Microbiology? Bacteria is the organism, Microbiology is the study of them and there is already a history article here. -- Azaroonus 18:12, 10 August 2006 (UTC)

A very fair point. It probably would be a better place. Evolutionary history, now that's different. Cheers, -- Plumbago 21:46, 10 August 2006 (UTC)

Hmmm. I like it. I will have to see what I can dig up about that. It would be interesting to add some things about when Bacteria evolved, hypotheses based on molecular clocks and perhaps fossil records. Could also discuss the theories of when they broke from Archaea and Eukarya and the chloroplast/mitochondria symbiosis from Bacteria. Not my main field but I will give it a try.-- Azaroonus 13:01, 11 August 2006 (UTC)

I could edit the image to include a plasmid? Wolfmankurd 11:24, 29 May 2006 (UTC)

Bacteria were formerly classified in the kingdom Monera, but are now given their own domain.

As far as I know,Archaea are still counted as bacteria, the term being a structural rather than phylogenetic one; the domain is called Eubacteria on the tree of life and elsewhere. Also, isn't the five kingdom system still prevalent among biologists, despite its fairly clear inadequacies?

Viewing Bacteria as the super-domain over EuBacteria and Archaebacteria is outmoded and has been superceded by the view that Archaea actually have much more in common with Eukaryota than had been thought. See http://www.ncbi.nlm.nih.gov/Taxonomy/taxonomyhome.html for more information. Note also that the tree of life has shifted to the three domain view, although they do use the term Eubacteria. Note also that all of the alternative high level taxonomies presented on the tree of life site show Archaea as closer to Eukaryota than to Bacteria.

I agree. So why do we still have a separate article on Eubacteria? I vote that we merge the contents of that article with this one. We then should delete the contents of that article and redirect it to here. Any thoughts? RK

It is definitely true that most biology texts still have the five kingdom view and that many biologists who don't work in systematics will still reiterate when asked. If they review the current literature, most convert quickly to the three domain view (in my limited experience observing this process). -- TedDunning

Reviewing the current literature shows a lot of implicit assumption of the three-domain system, but not a lot of evidence for the phylogenetic hypothesis it entails. In particular Mayr and other opponents argue that the Eubacteria are paraphyletic, and while this view does not have wide support, I haven't found any arguments for their monophyly (except based on Woese's original progenote hypothesis, which he has since disavowed). If someone more familiar with the subject could add these, I would be very grateful.

Actually, here in central Europe, the view that I have found to be prevalent is to refer to Eubacteria, and Archaea.

Bacteria's is more a general term when the talker doesnt want to distinguish too much. I think the article should reflect the current opinion about the phylum as well. —The preceding unsigned comment was added by 80.108.103.172 ( talk) 02:40, 20 January 2007 (UTC).

Some thoughts:

• Living things shouldn't point to three-domain system, since one is a group and the other is a particular classification of that group, which is not universal.

• On that, the Bacteria may be treated as one of six (or more) kingdoms instead of as a domain. I got the general impression from talk pages that we were planning to use this system, but that doesn't necessarily mean we were planning to abandon domains. How should we rank this group?

• Living things is not a standard taxon, at least not in formal schemes, and is definitely never given a rank like Global Realm. It should not appear as such in the taxobox. What, if anything, should replace it? If nothing, what becomes of the Scientific Classification subbox for top-level groups?

I substantially agree with what you-all have said. But I felt the need to indicate an overall category in some way to give relevance to domain, so that's what I came up with. Any better alternatives are welcome! I strongly feel that we should retain the three-domain system, and that it's much more cladistically correct. I also feel that the taxoboxes should reflect cladistics as much as possible, though it's not always easy. The reason I pointed "living things" the the "Three-domain system" was to point people to an explanation of the organization, since I know a lot of people still aren't familiar with this. jaknouse 15:54 Apr 2, 2003 (UTC)

I changed it a bit so that it conforms to the convention already established in the other Kingdom articles. I've also never heard of "Global realm" being part of any scientific classification system and it does not make much sense to link to organism there - of course we are taking about organisms. It is best to link that on the first line of the article - not in the taxobox which gives the impression that "Global realm" is an actual classification. The current taxobox also much more clearly illustrates the relationship between the Kingdom and Domain - there was no link to the Kingdom classification before (NOTE: I know that the three domain system and the 6-kingdom system are really two different classification systems but it would be a mistake not to capitalize on the actual compatibility between the two systems - at least at the Kingdom/Domain interface). -- mav 21:32 10 Jun 2003 (UTC)

I disagree, I think listing both domain and kingdom is a mistake. Modern classifications generally don't use both in discussing these groups, and those that do may not recognise a single kingdom in each prokaryotic domain. It removes the main point of the three domains, which you will remember were originally intended as replacements for the kingdoms. I don't think the very small amount of compatability we gain by conflating the two systems is worth it. If we want to use three domains, let's use three domains, and if we want to use six kingdoms, let's use six kingdoms. -- Josh

We could easily get away with removing the domain classification from the eukaryotic kingdoms but the problem here is that bacteria and archea are both kingdoms and domains. That said if anything were removed from here it should be the domain classification since it never really has caught-on in any way comparable to the way multiple kingdom systems have. -- mav

I disagree entirely. The Archaea were first introduced by Woese as the third domain of life, and they are generally ranked accordingly. Systems which treat them as a kingdom are derivative, less common, and less recognizable, while systems which treat them as both are less prevalent still. Moreover, some sources divide them into several kingdoms, such as the tree of life. There is more support for a kingdom Bacteria, but this may be taken to include the Archaea, as is done by Cavalier-Smith, while the domain is unambiguous.

In general, I think the three-domain system is far better known than any of the multi-kingdom systems after Whittaker. There is a good reason these groups were being listed as domains: that is the way people think of them and are use to dealing with them. I think we should go with this, treating the eukaryotes in terms of kingdoms and the prokaryotes in terms of domains, instead of trying to force a less natural synthesis. -- Josh

We are using Whittaker with a slight modification by splitting Monera into Bacteria and Archea in order to make this system compatible with the main thrust behind the three domain system (Karl Woese of U of Illinois first proposed the 6-kingdom system before the 3-domain system was proposed if I recall though - but it was proposed to overcome the same major problems). I can't say I've worked much with Archea but I have worked a bit with bacteria and have always treated them as a kingdom, not a domain. I was taught the 5-kingdom system with the caveat that Monera is a poor excuse for a kingdom since it represents two very different branches of life (this is far worse than the "superkingdom" nature of Protista). Thus the split.

IMO there is no harm done mentioning both classification systems in all the kingdom taxoboxes. It is also my understanding the the domain classification system is subdivided into KPOCFGS just as the 6-kingdom system is (except with one level above kingdom). So why does the kingdom stuff need to be removed from the prokaryotic domains? Just because there is only one accepted kingdom in each of the domains doesn't mean that we should not report this. We do it all the time with lower-level taxoboxes where a family only has one extant genus. --mav

Woese certainly proposed three domains first. It's a little confusing because at some point he was calling them kingdoms, but throughout Bacteria and Archaea were ranked on par with the eukaryotes. That's why the Archaea are referred to everywhere as the third domain or kingdom of life. Based on his approach to microbial diversity, I would be surprised if he had ever proposed the six-kingdom system.

Do the prokaryotic domains each contain a single kingdom? They may be given as both domains and kingdoms in different systems, but that is not the same thing - e.g. the rotifers may be taken to be a class, but as a phylum they have three classes. Most sources don't seem to mention kingdoms for the prokaryotic domains, and those that do don't necessarily have one for each. The tre of life is a fairly notable source, and it casually mentions the "kingdom Crenarchaeota". Many of the pages on Nanoarchaeum did the same. In short, I don't think it's fair to say that what you are proposing is just reporting the classification system as it stands.

Treating the bacteria as a kingdom is a common practice, but as I said, this is mostly thanks to systems that do not separate out the archaea. I would argue that the three-domain system, not the six-kingdom system, is the most familiar of these. And at the moment, the de facto standard that wikipedia has been using is the former, treating Bacteria as a domain rather than a kingdom. So we don't need comptability with the latter, and if we intend to switch towards it, we should have a good reason.

All in all, then, I think listing kingdoms provides no information about relationships and provides misleading information about ranks, for the sole purpose of gaining compatability with a less common system that we don't need to follow. I don't understand why you think they're a good idea. -- Josh

"Woese certainly proposed three domains first." Not according to Campbell 5th Edition, page 499 ( ISBN  0-80531957-3), which reads; "Archeabacteria and eubacteria diverged so early in the history of life that many researchers, led by Carl Woese of the University of Illinois, first proposed a six-kingdom system: two prokaryotic kingdoms along with the four eukaryotic kingdoms." Page 495 also says in figure 24.10 when referring to a representation of the 3-domain system "This scheme assigns even more significance to the ancient evolutionary split between eubacteria and archeabacteria by using a superkingdom taxon called the domain. The phylogenetic rationale for this solution is discussed in Chapter 25 [above cite]. The domain Eukarya consists of the four kingdoms of Eukaryotic organisms." So this is the only reference I could find that hints at what the next taxon down from domain would be (in this case the text seems to imply that "kingdom" is the next level down).

The major issue I have with the 3-domain scheme is that I have yet to see any proposed taxonomy for this system below the top-level. If "kingdom" is not part of this system then that would make a total mess of the taxonomy of Eukarya because that leaves us with hundreds of phyla and divisions just below the top level. But if this system does have kingdoms only for Eukarya and not the other domains then I find such a system logically inconsistent. Actually the more I think about it the more I'm convinced that the 3-domain system isn't really about forming a useful taxonomy down to the species level and therefore doesn't really have a place in a taxobox (which is all about taxonomy). But I still do find the domain information interesting and wish it could stay. At the very least this info needs to be in the prose of the article - its inclusion in the taxobox has always been optional since it isn't really part of the 6-kingdom system. -- mav 19:40 11 Jun 2003 (UTC)

Sorry, my mistake. Archaebacteria was originally a kingdom, which Woese renamed Archaea when he promoted it to a domain. In that same revision, he also treated the Crenarchaeota and Euryarchaeota as kingdoms. In other works I have seen these further divided down to species, but generally on the assumption that they are phyla. The same is done with the Bacteria, which I don't think Woese gave kingdoms for. In both cases the kingdoms are skipped in at least some newer treatments.

But I don't think it's fair to say that the kingdoms are absent from the system, or that it's not about classifying organisms down to the species level. The problem is that the kingdoms aren't a stable part of the classification, because the relationships between the different groups aren't clear enough to introduce any that aren't redundant, and so tend to be ignored. It's very much like the protists: the domain is clear, the low-level groups are clear, but the stuff inbetween is uncertain and so tends not to be assigned a full and proper taxonomy. In such cases, I think the best thing for the taxoboxes to do is omit the confused ranks.

These pages have been treating the bacterial and archaean phyla as direct subgroups of the domains because, as far as I can tell, the most recent classifications of bacteria and archaea do the same. This is mirrored on some of the subgroups, and it seems to work well enough - at least I don't think it has caused anyone much confusion, especially if they are familiar with the concept of the domains. I don't see any reason we need to use kingdoms where most workers don't, but if they are that important to you, I would prefer the six-kingdom system to this weird hybrid. -- Josh

I'll have to ponder what you just said a bit before I decide what to do. I think you hit the nail on the head though about the intermediate-level taxons being in a great deal of flux... -- mav

OK. Upon further reflection I think you are right and that we should omit the taxons which are confused (such as the kingdom taxon for bacteria and archea - although a look at the cladistics of these domains seems to indicate to me that 3 kingdoms/next-level-down-taxon exist for archaea and 5 for bacteria - but the last thing I want to do is to go down the splitting route). In short we should stick to the taxons we are sure of. In this case the 3-domain system seems to make more sense for the prokaryotes so lets use that. In time I'm sure biology will work out the specifics of just how many kingdoms are in each domain. But not today. --mav

Thanks, mav. I'm not sure that having Kingdom: uncertain in the placement box doesn't suggest there would only be one, but beyond that it's a good solution. Just out of curiosity, what would the five bacterial kingdoms be? Most of the phylogenies I've seen have been too messy to permit such an easy split. --Josh

I'm not totally satisfied with the "Kingdom: uncertain" bit either. But then the whole situation with the taxonomy of the prokaryotes is not satisfying. Eventually some explanation in the text about this is warrented. I was mistaken about the bacteria kingdom bit (I was looking at a simplified cladogram that only focused on the top five bacteria groups; spirochetes, chlamydias, gram-positive bacteria, cyanobacteria and proteobacteria); there are in fact about 12 bacterial groups according to Campbell and I really am not qualified to say whether or not they would be phyla or kingdoms. --mav

Until very recently it was believed that Bacteria were one of the earliest forms of life to develop, and that more developed organisms developed from them. In 1998, however, three New Zealand scientists proposed that the simplicity of bacteria was not a product of their primitivness, but rather indicated the sophistication of their development. Bacteria lack much of the duplication and unecessary genetic structure found in other organisms, however, it is now known that this duplicated structure was almost certainly essential for early life to evolve. Bacteria rather than being primitve are, in fact, a stremlined creature that has dropped the unecessary genetic baggage of the past and are probably more recent developments that bulkier protazoa. This simplicty allowed bacteria to survive in a much wider array of locations than other more complex organisms that could not properly duplicate themselves in adverse surroundings. Most important was the ability of bacteria to survive and replicate in much higher temperatures than other organisms which has lead to vast bacteria populations below the Earth's surface.

I have an extremely difficult time believing this is anything like the mainstream view. It might be possible that the first organisms must have had more complicated genetic mechanisms might be, but I'm not sure how would be sure. And the idea that bacteria are more recent than protozoa is in direct contradiction with current thinking, which suggests that protozoa originated through endosymbiotic events involving bacteria. I'm going to temporarily remove this from the article, but leave it here in case someone more qualified feels they can NPOV it.

What is going on with the article history at the end of the article? There's hidden text which says, "This section is required under the GFDL here, as we have imported text from a third party under the terms of the GFDL. Please only edit this section as allowed for by the GFDL.". What? Is this required for all articles? I don't think this assertion is true. RickK 08:54, 18 Jan 2004 (UTC)

Yeah, that was odd. Fixed. -- mav 09:00, 18 Jan 2004 (UTC)

There are six kingdoms. Not five.

I was surprised that the article didn't mention spores. I also saw that the spores article is limited to plant-life spores. Can anyone who really understands all this add something on bacterial spores? David Thrale 23:15, 17 Mar 2004 (UTC)

I would like to reverse a number of the decisions we made about taxonomy, above; anyone interested is invited to wikipedia talk:WikiProject Tree of Life. Dita 18:39, 30 Aug 2004 (UTC)

I've been noticing all the automatic changes (by bot User:CanisRufus) linking bacteria in the text to bacterium, and disguising it with a pipe.

Why is the article even at bacterium? Surely bacteria is the vastly more common term. They are very rarely referred to in the singular.

Are there any objections to moving this page to bacteria, which is currently a redirect?

The article is titled bacterium because the Wikipedia conventions say artciles should be singular nouns when possible. In this case, I think we're in a grey area since the plural form is much more common, but not exclusive. Jmeppley 16:41, 4 Jan 2005 (UTC)

The name as it stands now is clearly wrong, since the article is really about the kingdom Bacteria - it really has nothing to do with plural vs. singular as there is no such thing as kingdom Bacterium. I am changing it. Fawcett5 19:26, 7 September 2005 (UTC)

• hmm, but the parallel article animal is also about the kingdom animalia, and its title is singular. —  brighterorange ( talk) 14:55, 10 May 2007 (UTC)

I think we just have to ask ourselves "What are people going to type into a search engine"? I think "bacteria" is going to be overwhelmingly the most common word. TimVickers 15:49, 10 May 2007 (UTC)

The beginning of the article states that bacteria are the most 'abundant' form of life. I have no arguments that in number of individual organisms and most likely in the number of cell, bacteria are the most 'abundant', but I was under the influence that by sheer bio mass, plants are the most 'abundant' form of life. any one have any proof one was or the other? -Adenosine- 09:26, Mar 7, 2005 (UTC)

Bacteria are about 1/2 of living tissue by mass, and more than 100.00% by number of living organisms. Of course, we need references. The author below knows something, obviously.

I think that this was, until quite recently, the conventional wisdom. But recent discoveries have expanded the range of conditions in which we expect to find bacteria. This includes much of the crust that was assumed to be considered uninhabited rock and superheated water. (Effectively, the biosphere is a few miles thicker than we realized, and most of that is inhabited by bacteria and archaea.) I get the impression that most people who think about these things would now agree that prokaryote biomass outweighs eukaryote biomass. But I've only seen a couple calculations and none treat archaea and bacteria differently. I also get the impression that we are constantly revising the limits of bacterial growth, but we have a pretty good grasp of where the plants are.

But I agree that 'abundant' is open to interpretation and should maybe be replaced with something more specific and also backed with a citation. Jmeppley 18:51, 8 Mar 2005 (UTC)

Don't forget the atmosphere and space. Perhaps I'll put 'space' as supposed for now as it is still under investigation. There is certainly bacteria that lives primarily in the atmosphere. It is possible some of those escape and continue to live in space (not propogate, they most likely lay dormant for an undisclosed amount of time (even millions\billions of years)) then under the right circumstances start to propogate and mutate once favorable conditions are encountered.

I should also point out -What a small entry for something such as Bacteria-. These things are essential to all life on earth (including the nessessary interactions inside our own bodies needed to sustain ourselves). The oxygen based bacteria had a large influence on oxygen breathing organism today (such as ourselves). If other forms of bacteria turned out to have dominated early on, our world may not have been oxygen based. Methane based bacteria did almost dominate over oxygen based bacteria.

Q: But did the bacteria help create the oxygen (in sybiosis with plants?). Where would have all the methane come from?

Why is the taxbox green now? Vandalism or some sweeping change I am unaware of? Onco p53 21:31, 10 May 2005 (UTC)

Vandal. JFW |  T@lk 22:16, 10 May 2005 (UTC)

From the text: In 1956 Copeland gave them their own kingdom Mychota, later renamed Monera, Prokaryota, or Bacteria. But it's not clear to me who this is refering to. A quick search turned up Herbert Copeland, but it also might have been Edwin Copeland. Anyone know? Matt 15:56, 26 May 2005 (UTC)

Herbert Copeland -- see publication list in article. -- Macrakis 17:05, 20 Jun 2005 (UTC)

Why's this picture missing:

I removed the reference to it in the article because I can't find the picture. I thought it was a great resource. Please someone rescue this pic! Adenosine | Talk 01:01, 10 December 2005 (UTC)

Would it be possible to put links in the text or precisions as to what info is taken from what document ? Thank you Bragador 19:40, 21 December 2005 (UTC)

bacteriology sience is still up to date for ever there is new serotypes and some times shifting in them from group to group and new features to there pathogenisity and virulence factors . -- 217.144.4.73 20:50, 6 January 2006 (UTC) -- 217.144.4.73 20:50, 6 January 2006 (UTC)

Approximately how many species of bacteria are known to exist in each subgroup?-- StAkAr Karnak 04:58, 11 March 2006 (UTC)

This is difficult to answer for sure, largely because the status of bacterial taxonomy is constantly changing, including thoughts about the identities and relationships between the major groups. All in all there are approximately 8000 bacterial species formally recognized but this is a HUGE understatement of the total bacterial diveristy in existence - the problem is there is no universally accepted species concept for prokaryotes making for difficulties in classification. There are huge numbers of sub-specific strains known but almost all are not formally classified. The other problem is that most microbiologists will say that only 1% of all microbes can currently be isolated in pure culture meaning that the current picture of microbial diversity is unreliable. I've seen reviews that suggest that there are ~40 main groups of bacteria of which we can study about 20 and maybe 10 in any sort of breadth. I agree that the taxonomy of bacteria pages should be reworked (perhaps using gene trees generated using e.g. the ribosomal database project or ARB software) but this will take time and perhaps more-than-layman's expertise. As it stands now it's hard to tell what links lead to what information. Jlk3 00:16, 20 March 2006 (UTC)

Bacteria are about 1/2 of living tissue on Earth by mass, and more than 100.00% by number of living organisms. Of course, we need references.

Can we move this article to "Eubacteria", since technically that is what this article is about (i.e. no archea).- Moshe Constantine Hassan Al-Silverburg | Talk 19:39, 31 May 2006 (UTC)

Or at least make that clearer. Eubacteria redirects here, but I couldn't find the word in the text (it might be there, but it's certainly not salient). Note that some wikipedias have separate pages, for example fr:Bacteria and fr:Eubacteria. Rigadoun (talk) 19:03, 11 August 2006 (UTC)

The naming of Bacteria is a closed case. A citation from a book that is more than 10 years old:

To avoid the perception that all prokaryotes are closely related (which they are not), the terms Bacteria and Archaea have replaced eubacteria and archaebacteria... Biology of Microorganisms 7th ed, Brock, 1994

I agree though that a short article that explains that eubacteria is an old name for Bacteria and maybe a link to Bacteria AND an article that describes the nomenclature system.-- Azaroonus 12:58, 12 August 2006 (UTC)

Yes, that would be helpful. Could we add something like this to near the top of this article as well: "The kingdom Bacteria was formerly known as Eubacteria to distinguish from Archaea, formerly known as Archaebacteria. The new names were adopted in year X to emphasize that there was no close relationship between them." (And use your book as an inline citation.) That would clarify the situation for those of us who studied biology before the names were changed, which certainly was recent enough that people are apt to run into the old nomenclature. Rigadoun (talk) 16:04, 12 August 2006 (UTC)

Just a clarification. Are bacteria not in the kingdom "Monera"? Adenosine | Talk 19:37, 12 August 2006 (UTC)

Adenosine: in the modern classification system used by biologists, Bacteria are not a part of any Kingdom but a Domain (the new name for the highest of the classification levels) unto themselves. See Scientific Classification and three-domain system. These are good srticles and up-to-date with current practise as far as I can see.

Anonymous: I understand how a domains work, I even understand why they're around, but as a modern biologist I take offense to you telling me the are no kingdoms. I do regualarly use kingdoms, I just place domains one step higher. Plants and Animals are certainly in the same domain, and so are protists, but are we not all separated by the less than arbitrary classification of kingdom. If the domain 'Eubacteria' contains only the kingdom of 'Monera,' does the redundant classification void the kingdom specification!? If you were to read the question that I responded to, it asked about 'kingdom', even though a question on domain would have been poignent, my responding question was appropriate Adenosine | Talk 08:30, 15 August 2006 (UTC)

Adenosine, just for reference, the anon (actually Azaroonus, you split their comment in two) was responding to your suggestion that bacteria were in protista (which you subsequently tweaked to monera). So you can perhaps see why they might be assuming you weren't a biologist. Anyway, kingdoms (at least for distinguishing life's major branches) are a bit passe, but from what I've been able to gather from WP (being, now, many years removed from my original degree) it's still a very fluid subject, with a few competing high-level systems. It does look like Kingdom Monera has had its day though - putting together bacterial groups as unrelated as the (eu)bacteria and archae, while separating groups as closely related as the eukaryotes is well past its sell-by date. Retaining the other kingdoms (much like the name "bacteria") makes sense from a practical point of view, but it does then require higher order organisation. Hence domains. Cheers, -- Plumbago 08:55, 15 August 2006 (UTC)

Well, sorry for spliting the comment (it was very unclear). The Protist slip on my part was just a stupid mistake. I did mean monera from the start, I hoped no one would catch me correcting myself. I agree with you Plumbago; you struck my point on the head, and you did it much more polietly, and concisely. As someone who is a biologist by training and profession (even if I may not seem it) I just wanted to lend my vote that if kingdoms aren't used by everyone, they are certainly used by me and people I know. WP's coverage on this is very sparse. I tried to re educate myself on this subject and I found only contradictions, ambiguities, and confusion. Hope it all gets figured out Adenosine | Talk 08:34, 16 August 2006 (UTC)

No worries!! I think it is great we share ideas and our interest in the topic, we should not bother being offended by one another :-) I, too, was guilty of imprecison in my wording because above when I said "modern classification system used by biologists" I should have written microbiologists or maybe even bacteriologists because, as you point out, many biologists (read: those that study eukaryotes) seem to use kingdoms in their classification. But this article is about Bacteria so what system do Bacteriologists prefer?

The three domain system is prefered by microbiologists because is based on molecular taxonomy, specifically 16S/18S rRNA gene comparison, while the 5 kingdom system is rooted in phenotypic characteristics. In my opinion, it is phentypic v. molecular that the major difference - the names are just related to the basis of the classifiaction system used. The reason that microbiologists, particularly microbial ecologists, prefer a molecular taxonomy system is that phenotypic classification does not work very well to classify microbial diversity. Bacteria (and Archaea for that matter) do not have the diversity of structures that even unicellular Eukarya have and therefore phenotypic classification has been based on traits like the ability to metabolise certain substrates etc. Hence for years that thought the Pseudomonas and Burkolderia were the same bug (Gram negative rod, similar physiology), only to find out that they were each in a different Phylum (Gammaproteobacteria and Betaproteobacteria, respectively). Imagine mistaking a human for a jellyfish ;-) Physiological traits in bacteria have not just been inherited vertically but also horizontally meaning that evolutionarily unrelated species can share similar traits that evolutionarily closely-related species do not. These difficulties can be overcome with molecular taxonomy... thus microbiology gained a systematic way of categorising organisms.

This system has been adopted by may eukaryotic biologists, but as far as I understand (not being a eukaryotic biologist) the phenotypic classification is so applicable to understanding eukaryotic evolution, that molecular classification is used to add sensitivity to the existing groupings, which are still strongly rooted in phenotypic classification. In Bacteriology phenotypic traits are used to add sensitivity to the evolutionary groups determined by molecular classification. For this reason, I think that molecular taxonomy and three-domain system of classification should also be the main system used in the Bacteria article. We of course need to discuss the phenotypic classification system, indeed this is still used in many labs particularly in clinical microbiology, and is still important. Ideally we need to nunt down some references to support these assertions, such that it is less POV and more NPOV if this is to get into the article itself. -- Azaroonus 18:29, 17 August 2006 (UTC)

All sounds great. I would love to see a standardized taxonomy system for all organisms on wikipedia, bacteria or not. You can see what Wikispecies uses [ [1]]. Would this be a suitable system for bacteria & archaea AND plant, animals etc.????? Adenosine | Talk 22:25, 17 August 2006 (UTC)

This is not a simple topic and there is no uniform system. Is Wikipedia is the right place to develop a standardised nomenclature system for biology? I guess that it is a our role to figure out which systems are in use in the field and present these.

The system that you link to is the Linnaean (or 5 kingdom) system. Yes, domains are present in that table in Section 1 as a grouping above Kingdom, fine for Eukaryotes because 4 kingdoms are under Eukarya but how do you fit the Bacteria and Archaea into the Kindom Monera? It also says Domains are... not accepted by all biologists . I read this to mean that many biologists disagree that Domains are compatible with this system. The existence of the Domains is not really in question because they are a nomenclature from another valid system. Again the problem with using the system hat you suggest is that it is based on phenotype:

Kingdom: Animalia (with eukaryotic cells having cell membrane but lacking cell wall, multicellular, heterotrophic) "from section 2 of [ [2]

Bacterial classification cannot alone rely on such phenotypic classification alone because it makes classification very difficult. Hence the molecular classification and that is three-domain. It does not make the others wrong, just not useful for microbiology. I have been looking around a bit. Bergey's Manual of Sytematic Bacteriology uses the three-domains in thier "Taxanomic Outline of Prokaryotes" the other ranks being: phylum, class, order, family, genus, species. They write "The rank of Kingdom is not used to prevent conflicts with the Botanical Code where some overlap exists" The Judicial Commission of the International Committee on Systematic Bacteriology ( Meeting procedings) put out the "The International Code of Nomenclature of Prokaryotes" which are the guidelines used by bacterial taxonomists. I am trying to read this and figure out the system that they use. -- Azaroonus 09:05, 18 August 2006 (UTC)

Thanks Rigadoun .I will take you comments on board. I can see that this is a topic that demands attention and as I am working on rewriteing the article (see above), I will be sure to put these links and explainations prominently on the page - if no one else gets there first... :-) -- Azaroonus 10:55, 14 August 2006 (UTC)

Be sure to add citations or references in order to keep the GA status. Lincher 01:32, 21 June 2006 (UTC)

Nice article, but why is the title listed as the plural "Bacteria", while every other article title, (such as "Virus", for example) is in the singular? Could someone with permission to change the title amend this to "Bacterium"?

Bacteria refers to the entire domain "Bacteria." See Archaea.

I wonder when the media will stop "shocking" the world with all the new things that has more bacteria in it than a toilet seat. Soon, toilet seats will be the only sterile thing left on the planet ( Henningklevjer 12:05, 10 August 2006 (UTC))

The Spirulina page could use a serious factual overhaul. Is anyone interested in adding a little academic rigour?-- Niro5 12:42, 10 August 2006 (UTC)

> All bacteria reproduce through asexual reproduction (binary fission) which results in cell division. Two identical clone daughter cells are produced. Some bacteria, while still reproducing asexually, form more complex reproductive structures that facilitate the dispersal of the newly-formed daughter cells. Examples include fruiting body formation by Myxococcus and arial hyphae formation by Streptomyces. Whoever wrote it, it must be a joke, too many letters for a typo.

"Bacteria are organisms in the kingdom Monera ... The term "bacteria" (singular: bacterium) has variously applied to all prokaryotes or to a major group of them, otherwise called the eubacteria, depending on ideas about their relationships."

The term bacteria, as it is used in science, refers to a domain under the three-domain system. The first listed definition, as indicated in the Monera article, is obsolete and should not be used as the first sentence the reader sees. - ElAmericano ( dímelo) 21:33, 17 September 2006 (UTC)

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