42 THE OCEAN RIVER 



in the form of nonliving protein crystals. It is at least possible 

 that life originated from colloids during the first few hundred 

 million years of the ocean's existence, when a chance combi- 

 nation of favorable circumstances presented itself and caused 

 the molecules to rearrange themselves in a life-giving pattern. 



Almost certainly life began in the hot and somewhat brack- 

 ish seas, a billion years or more ago. It is also very possible that 

 the first forms of life were not true plants or animals, but 

 somewhat akin to bacteria or possibly viruses. True plants are 

 able to feed on simple salts and the carbon dioxide in air or 

 water, and are able, by means of chlorophyll, their green color- 

 ing matter, to use the energy of sunlight and so manufacture 

 their carbohydrate and protein food within themselves. Life 

 may have started when the earth was surrounded by a contin- 

 uous blanket of clouds, stormy with thunder and lightning and 

 almost completely shutting out the sunlight that plants must 

 have. Since animals are dependent on plants for their food 

 they could not have existed under these conditions. Moreover, 

 the atmosphere in the early days of the ocean may quite likely 

 have contained such gases as nitrogen, chlorine, and ammonia, 

 though lacking oxygen. Bacteria, unlike plants, are able to live 

 in the absence of sunlight, and some of them, like the present- 

 day iron and sulphur bacteria, are able to feed on the simple 

 chemical substances that must have been plentiful in the early 

 ocean. They alone among living creatures are able to extract 

 from such simple materials the energy needed to support life. 



Whatever form life took in the young ocean, it must have 

 gone through a long course of evolution before the first recog- 

 nizable fossils were formed. Long before this, as the seas cooled 

 and the dense cloud blankets began to disperse, sunlight broke 

 through and it became possible for chlorophyll or its early pro- 

 totype to develop in some of the primitive bacteria-like organ- 

 isms. Thus plant life came to the ocean. The evolution of 

 plants, even though they were still microscopic, provided the 



