CHAPTER XXVII 



THE ORIGIN OF LIVING MATTER 



The geologist tells us that life originated on earth about a thou- 

 sand million years ago. The oldest known fossil is from an 

 archeozoic pebble in a conglomerate of early Proterozoic age 

 found in Minnesota. Apparently, no specific name has been 

 given to this fossil. It is a blue-green alga related to the modern 

 Inactis or Microcoleus. The fossil must be at least nine hundred 

 million years old, if we accept, as most geologists now do, the 

 age determinations based on the rate of disintegration of radio- 

 active substances. Presumably, life originated at a time that, 

 geologically speaking, was not much more remote than this. 



When life began on earth, the world did not greatly differ, 

 physically or chemically, from what it is today. The sea was less 

 salty, and the temperature in general possibly more near that of 

 the tropics, but in the main it was a world similar to ours of 

 today. It is likely that certain fresh-w^ater Protozoa and algae 

 may still persist from the earliest periods of the earth's history, 

 because their environment has changed so little. 



Before living protoplasm could be produced, its simpler, yet 

 still very complex, constituents had to be formed. The first 

 significant step in the origin of living matter was the production 

 of an organic compound from inorganic substances. We start, 

 then, with a primeval world of water, carbon dioxide (in solution 

 and in the atmosphere), sunlight, and mineral matter. The 

 last mentioned will have existed both in true solution and in a 

 finely divided, colloidal state. This is apparently sufficient to 

 serve as the basis for the production .of a simple organic sub- 

 stance, such as formaldehyde (COo + H2O = CH2O -|- O2) or 

 possibly even a simple sugar (6CO2 -f 6H2O = 6CH2O -}- 6O2 = 

 C6H12O6 + 6O2) in a manner similar to that which occurs in the 

 plant. If theories on the mechanism of food synthesis (photo- 

 synthesis) in the plant are reasonably accurate, then water, 

 carbon dioxide, a catalyst, and solar energy are sufficient to pro- 



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