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KINGDOMS MONERA AND PROTISTA: 



TAXONOMIC SUMMARY 



Viruses (L. virus, slime or poison) — viruses 

 Kingdom Monera (Gr. moneres, single) — monerans 



Phylum Schizophyta (GT.schizo, cleave + phylon, plant) — bacteria 

 Phylum Cyanophyta {Gr. kyanos, blue + phyton) — blue-green algae 

 Kingdom Protista {Gr. protistos. first of all) — protistans or protists 

 Subkingdom Protozoa {Gr. protos. first + zoon, animal) — protozoans 

 Phylum Flagellata {h.flagellum, little ufhip) — flagellates 

 Phylum Sarcodina (Gr. sarcodes, fleshy) — sarcodines 

 Phylum Sporozoa (Gr. i/)oroi, spore + zoon) — spore animals 

 Phylum Ciliophora {h. cilium, eyelid + phoros, bearing) — ciliophorans 

 Class Ciliata (L. cilium) — ciliates 

 Class Suctoria (L. suctus, sucking) — suctorians 

 Subkingdom Fungi {L. fungus, a mushroom or fungus) — fungi 

 Phylum Myxomycophyta (Gr. my.xa, mucus + mykes, fungus + phyton) — slime molds or 



fungi 

 Phylum Eumycophyta (Gr. eu, good + mykes -t- phyton) — true fungi 

 Class Phycomycetes (Gr./)Ayloi, alga + mykes) — algal fungi 

 Class Ascomycetes (Gr. a.s^oj, bladder + mykes) — sac fungi 

 Class Basidiomycetes (Gr. basis, pedestal + mykes) — club fungi 

 Lichens (Gr. leichen, lichen) — lichens 



nucleic acids in a covering of protein; size ultra- 

 microscopic, from about 15 to 450 millimicrons (25 

 million millimicrons equals 1 inch); shape approxi- 

 mately spherical, rod-like, tadpole-like or poly- 

 hedral; all known forms are obligate parasites (within 

 their host's cells) and act as disease-producing 

 agents; probably parasitize all kinds of life; many 

 can be crystallized; multiply very rapidly after enter- 

 ing a host cell by a process in which virus nucleic 

 acids cause the host's cell to form virus chemical 

 compounds, finally the virus compounds are as- 

 sembled into virus particles and the particles are re- 

 leased as viruses when the host cell is destroyed; 

 viruses' activities may be the cause of cancer. 



The viruses are a group that most classifiers of life 

 might like to ignore. One cannot satisfactorily 

 answer the question of whether they are living or non- 

 living. The problem may be centered around viruses 

 containing nucleic acids. Nucleic acids have three 

 properties which characterize life. First, these 

 acids are chemical information carriers. Through 

 their chemical properties, they contain the plans 

 for synthesizing proteins. More specifically they 

 are hereditary units or genes that provide the genetic 

 code or plan of chemical reactions that determine the 



eventual traits of an organism. Second, nucleic acids 

 are capable of making exact copies of themselves. 

 This is the ability that allows genes to duplicate 

 themselves. Finally, although nucleic acids are 

 extremely stable compounds (they generally are not 

 altered in most earth environments), on rare oc- 

 casions minor changes in chemical structure can 

 take place. Such changes are the source of gene 

 mutation, hence evolution. Therefore, viruses con- 

 tain the materials that control evolution and they are 

 able to mutate and evolve. 



Because the properties of nucleic acids are char- 

 acteristic of organisms, it is difficult to separate 

 viruses from life. However, a virus appears to be 

 much less than any organism. For example, some 

 viruses definitely originate from nucleic acids that 

 become separated from certain cells. Although all 

 viruses may not have been formed from cell frag- 

 ments, it is difficult to imagine those viruses that 

 originate as fragments being complete organisms. 

 Also, it seems impossible for one organism to be the 

 parent of a remotely related individual. 



The activity of viruses leads to further difficulty 

 in diagnosing their living or nonliving status. 

 Viruses in air or water are inert and seemingly 

 nonliving. However, upon contacting a cell or cell- 



