History Monera

1 history

1.1 haeckel s classification
1.2 subsequent classifications
1.3 rise prominence
1.4 three-domain system

history

haeckel s classification

tree of life in generelle morphologie der organismen (1866)

traditionally natural world classified animal, vegetable, or mineral in systema naturae. after development of microscope, attempts made fit microscopic organisms either plant or animal kingdoms. in 1676, antonie van leeuwenhoek discovered bacteria , called them animalcules, assigning them class vermes of animalia. due limited tools — sole references group shape, behaviour, , habitat — description of genera , classification extremely limited, accentuated perceived lack of importance of group.

ten years after origin of species charles darwin, in 1866 ernst haeckel, supporter of evolution, proposed three-kingdom system added protista new kingdom contained microscopic organisms. 1 of 8 major divisions of protista composed of monerans (called moneres haeckel), defined structureless , homogeneous organisms, consisting of piece of plasma. haeckel s monera included not bacterial groups of discovery several small eukaryotic organisms; in fact genus vibrio bacterial genus explicitly assigned phylum, while others mentioned indirectly, led copeland speculate haeckel considered bacteria belong genus vibrio, ignoring other bacterial genera. 1 notable exception members of modern phylum cyanobacteria, such nostoc, placed in phylum archephyta of algae (vide infra: blue-green algae).

the neolatin noun monera , german noun moneren/moneres derived ancient greek noun moneres () haeckel states mean simple , means single, solitary . haeckel describes protist genus monas in 2 pages monera in 1866 book. informal name of member of monera moneron, later moneran used.

due lack of features, phylum not subdivided, genera therein divided 2 groups:

die gymnomoneren (no envelope [sic.]): gymnomonera

protogenes — such protogenes primordialis, unidentified amoeba (eukaryote) , not bacterium
protamaeba — incorrectly described/fabricated species
vibrio — genus of comma-shaped bacteria first described in 1854
bacterium — genus of rod-shaped bacteria first described in 1828. haeckel not explicitly assign genus monera.
bacillus — genus of spore-forming rod-shaped bacteria first described in 1835 haeckel not explicitly assign genus monera kingdom.
spirochaeta — thin spiral-shaped bacteria first described in 1835 haeckel not explicitly assign genus monera.
spirillum — spiral-shaped bacteria first described in 1832 haeckel not explicitly assign genus monera.
etc.: haeckel provide comprehensive list.


die lepomoneren (with envelope): lepomonera

protomonas — identified synonym of monas, flagellated protozoan, , not bacterium. name reused in 1984 unrelated genus of bacteria.
vampyrella — classed eukaryote , not bacterium.



subsequent classifications

like protista, monera classification not followed @ first , several different ranks used , located animals, plants, protists or fungi. furthermore, häkel s classification lacked specificity , not exhaustive — in fact covers few pages—, consequently lot of confusion arose point monera did not contain bacterial genera , others according huxley. first recognized kingdom enderlein in 1925 (bakterien-cyclogenie. de gruyter, berlin).

the popular scheme created in 1859 c. von nägeli classified non-phototrophic bacteria class schizomycetes.

the class schizomycetes emended walter migula (along coinage of genus pseudomonas in 1894) , others. term in dominant use in 1916 reported robert earle buchanan, had priority on other terms such monera. however, starting ferdinand cohn in 1872 term bacteria (or in german bacterien) became prominently used informally describe group of species without nucleus: bacterium in fact genus created in 1828 christian gottfried ehrenberg additionally, cohn divided bacteria according shape namely:

spherobacteria cocci
microbacteria short, non-filamentous rods
desmobacteria longer, filamentous rods , spirobacteria spiral forms.

successively, cohn created schizophyta of plants contained non-photrophic bacteria in family schizomycetes , phototrophic bacteria (blue green algae/cyanobacteria) in schizophyceae union of blue green algae , bacteria later followed haeckel, classified 2 families in revised phylum monera in protista.

stanier , van neil (1941, main outlines of bacterial classification. j bacteriol 42: 437- 466) recognized kingdom monera 2 phyla, myxophyta , schizomycetae, latter comprising classes eubacteriae (3 orders), myxobacteriae (1 order), , spirochetae (1 order); bisset (1962, bacteria, 2nd ed., livingston, london) distinguished 1 class , 4 orders: eubacteriales, actinomycetales, streptomycetales, , flexibacteriales; orla-jensen (1909, die hauptlinien des naturalischen bakteriensystems nebst einer ubersicht der garungsphenomene. zentr. bakt. parasitenk., ii, 22: 305-346) , bergey et al (1925, bergey s manual of determinative bacteriology, baltimore : williams & wilkins co.) many subsequent editions) presented classifications.

rise prominence

the term monera became established in 20s , 30s when rightfully increase importance of difference between species nucleus , without, in 1925 Édouard chatton divided living organisms 2 empires prokaryotes , eukaryotes: kingdom monera being sole member of prokaryotes empire.

the anthropic importance of crown group of animals, plants , fungi hard depose; consequently, several other megaclassification schemes ignored on empire rank maintained kingdom monera consisting of bacteria, such copeland in 1938 , whittaker in 1969. latter classification system followed, in robert whittaker proposed 5 kingdom system classification of living organisms. whittaker s system placed single celled organisms either prokaryotic monera or eukaryotic protista. other 3 kingdoms in system eukaryotic fungi, animalia, , plantae. whittaker, however, did not believe kingdoms monophyletic. whittaker subdivided kingdom 2 branches containing several phyla:

myxomonera branch

cyanophyta, called cyanobacteria
myxobacteria


mastigomonera branch

eubacteriae
actinomycota
spirochaetae

alternative commonly followed subdivision systems based on gram stains. culminated in gibbons , murray classification of 1978:

gracilicutes (gram negative)

photobacteria (photosynthetic): class oxyphotobacteriae (water electron acceptor, includes order cyanobacteriales = blue green algae, phylum cyanobacteria) , class anoxyphotobacteriae (anaerobic phototrophs, orders: rhodospirillales , chlorobiales
scotobacteria (non-photosynthetic, proteobacteria , other gram negative nonphotosynthetic phyla)


firmacutes [sic] (gram positive, subsequently corrected firmicutes)

several orders such bacillales , actinomycetales (now in phylum actinobacteria)


mollicutes (gram variable, e.g. mycoplasma)
mendocutes (uneven gram stain, methanogenic bacteria known archaea)

three-domain system

in 1977, pnas paper carl woese , george fox demonstrated archaea (initially called archaebacteria) not closer in relationship bacteria eukaryotes. paper received front-page coverage in new york times, , great controversy initially. conclusions have since become accepted, leading replacement of kingdom monera 2 kingdoms bacteria , archaea. minority of scientists, including thomas cavalier-smith, continue reject accepted division between these 2 groups. cavalier-smith has published classifications in archaebacteria part of subkingdom of kingdom bacteria.