Themes of Plant Biology
Prokaryotes and Viruses
Attributing life-or-death importance to organisms too small to be seen without great magnification is difficult, but consider that the prokaryotes:
-
Decompose complex organic molecules and return to the soil and air the elements needed for growth of all organisms.
-
Participate in complex biogeochemical webs that concentrate minerals—iron, manganese, copper, and others.
-
Maintain soil fertility by fixing atmospheric nitrogen, thus assuring the supply of available nitrogen for protein and nucleic acid synthesis by all organisms.
-
Are the base of food webs on land and in the oceans.
-
Are crucial links in the sulfur, phosphorus, carbon, oxygen, and nitrogen cycles.
-
Using novel metabolic pathways, both discharge into the atmosphere and extract from it all of the major reactive gases: nitrogen, oxygen, carbon dioxide, carbon monoxide, sulfur-containing gases, hydrogen, methane, and ammonia.
