CHAPTER X 

 Symbionticism and Organic Evolution 



Various theories and hypotheses have been advanced 

 at different tunes to explain the nature of the origin of life 

 upon the earth. It is generally beheved that certain 

 chemicals, under the influence of unknown extrinsic factors, 

 were combined in the formation of the first living matter. 

 Some authors have attempted to suggest the nature of the 

 substances supposed to have united under peculiar condi- 

 tions of temperature, moisture and light. Some have held 

 that ''bions," or particles of living matter, were first trans- 

 ported to the earth from some other planet. Numerous 

 attempts have been made artificially to produce Uving 

 matter, but these have all ended in failure. While modern 

 researches have extended our knowledge of living matter, 

 we are far from possessing a full understanding of the 

 nature of protoplasm. Until living matter can be produced 

 artificially, one theory on the nature of its origin, perhaps, 

 has as much value as another. 



There is more or less agreement among biologists that 

 the first or primordial Hfe on the earth must have been of a 

 bacterial nature. Osborn ('17) beheves that 'Tn the origin 

 of hfe bacteria appear to he halfway between our hypo- 

 thetical chemical precellular stages and the chemistry and 

 definite cell structure of the lowhest plants, or algae." 

 The environmental conditions on the earth at the time of 

 the origin of the first life, Imiit the nature of the first living 

 organisms to such forms as were capable of existing on 

 inorganic materials. 



In their power of finding energy or food in a lifeless world the 

 bacteria known as 'prototrophic, or "primitive feeders," are not 



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