Simple Life 



In this taxonomic classification the Kingdom Mo- 

 nera includes the bacteria and blue-green algae; the 

 Kingdom Protista includes four phyla classified by 

 some taxonomists as one-celled animals (protozoans) 

 plus the slime molds and the true fungi. Of these, 

 only the true fungi are so conspicuous that they are 

 commonly observed in nature. (Mushrooms, plant 

 rusts and smuts, and bread mold are examples of true 

 fungi.) However, many species of monerans and 

 protistans are macroscopic; the reader probably has 

 observed many of them, even if he did not know what 

 they were. 



Monera and Protista probably are closely related; 

 however, the time of common ancestry is remote, per- 

 haps well over a billion years ago. Both kingdoms 

 contain many species that appear to be single-celled 

 organisms whose primary organization is within a 

 single mass of protoplasm. Although their organiza- 

 tion may appear almost identical, monerans are not 

 as complexly organized as are the protistans (e.g., 



monerans have no distinct central cell body, or 

 nucleus, and protistans have a highly organized 

 nucleus), this contrast from lower to higher com- 

 plexity probably reflects a major step in the early 

 evolution of life. It is likely that the Monera organi- 

 zation of today represents one of the steps prior to 

 the complex organization found in most Protista and 

 in most true cells found in plants and animals. The 

 Monera are believed to be derivatives of the step in 

 the origin of life where groups of individual hereditary 

 units, or genes, were clumped into larger groups. 

 This nuclear material stage likely preceded chromo- 

 somes containing genes and a distinct nucleus — 

 that stage now represented by Protista. Therefore, 

 though superficially similar, from a structural 

 point of view the Monera and the Protista are very 

 different. This difference is implied by treating the 

 Monera as having protoplasmic organization and the 

 Protista as having accllular (or unicellular) organi- 

 zation. 



VIRUSES 



Prior to discussing the Monera and Protista, we 

 will outline the problem created by viruses. Viruses 

 are important because they are disease-producing 

 agents. In man viruses cause many serious disor- 

 ders, including poliomyelitis, influenza, and chronic 



hepatitis. In addition to this they are of some con- 

 cern in the origin of life and even in the question of 

 what is life. 



Diagnosis: complex chemical organization without 

 indication of cell-like structure; chemicals are mostly 



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