BILD 3 Chapter Notes - Chapter 18: Slime Mold, Nitrogen Cycle, Monera
26 Dec 2018
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Microbes everywhere: on average, human has one trillion bacteria on skin. 100,000/cm2: more bacteria in gut and nasal passages, some bacteria have no detectable function (intestinal spirochetes) Bacteria here billions of years before humans, and humans depend on bacteria: humans can"t survive without them. They process wastes and make them usable again. They synthesize gut vitamins, etc: bacteria undergo nitrogen cycle so humans can intake nitrogen, microbes provide us with the air we breathe and keep atmosphere stable, microbes supply lots of breathable oxygen. Bacteria can reproduce more quickly: clostridium perfringens can reproduce in less than 10 minutes, with adequate nutrients, single bacterial cell can generate 280,000 billion cells in a day. In same period, human cell has single division: once every million divisions, produce mutant. Could cause advantage, like antibiotic resistance: bacteria can share information. Can take pieces of genetic code from each other. Any adaptive change in one area can spread to others.
