Microbiology Notes August 26, 2009 and August 28, 2009
Read: Look Smart article, Article from the microbiology website, and chapter I did not finish
- Bacteria are awesome because they are the dominant form of life on earth.
1. Some background on bacteria, the dominant form of life on planet earth
a. Numerical and mass dominance
• Way more individuals than individuals of other stuff
• So way more genetic diversity than among non-bacteria
• Bacteria are much more adaptable to changing environment than other kinds of living things
---—— = Scale
/ Bacteria every other living thing
• Bacteria overwhelmingly outweigh everything else put together
- Population of organisms
- Environment that population lives in changes
- Individuals with best traits in a given environment survive best, others die
b. Longevity Dominance
• Bacteria pre-date other kinds of life by ~ (about) 2 billion years.
• At least a few bacteria are able to survive virtually all environmental assaults: High Temperature, Pressure, Radiation, ect.
c. Environmental Dominance
• Bacteria are basically found in all parts of the earth deep in the ocean to high in the atmosphere.
• Bacteria are everywhere
• Bacteria produce oxygen we breathe and in the environment.
• Bacteria shape our environment
d. Infectious diseases
• Disease caused by bacteria or viruses
• Symptoms from organisms growing in host
• Lead cause of death on planet earth.
• They kill us better than we kill them!
e. Normal Flora
• Bacteria that live in or on our bodies (bacteria in your body that live there normally)
• Necessary for life
Ex. E. coli makes Vitamin K
Clotting Factors in blood
Ex. Gut bacteria digest food with a little help from enzymes
Ex. Maintain skin health
Ex. Immune System – bacteria protect us from other bacteria diseases
2. Spontaneous Generation
Hypothesis: life can come from non-living material – idea = spontaneous generation
Support: Stuff grows in broth, and I didn’t put it there
Disproving Spontaneous Generation: Pasteur: Swan-necked flask
Keeps bacteria out but air in
3. The Germ Theory of Disease
a. Previous ideas about disease causation: Humors
Drain fluid causing problems (blood) – Humors theory. – cures disease
Humors: Blood gets out of balance, people get sick, and bleeding will fix it.
Was it reasonable to believe in humoral imbalances as a cause for diseases? What support did doctors have for that belief?
b. Previous ideas about disease causation: Miasmas
Miasmas – badness/poisons in the air. You can sense the poisons because it smells bad. Bad Air Poisons people! Lose the bad air, people will be well.
Was it reasonable to believe in Miasmas as a cause for epidemics? What support is there for this belief?
c. John Snow and the Broad Street Pump
Thought of water was bad not the air. The water came from different sources and went to different parts of the river which is why the one part of the river had lots of death and some had few to no deaths.
Are there diseases caused by microorganisms that are exceptions to Koch’s Postulates? Why?
Pasteur – molecular theory, pasteurization, fermentation, and vaccines
Koch’s – anthrax spores (discovered)
Read over kochs postulates. Think about what they discovered
Find specific suggestions about question and see if Pasteur could have come up with Koch’s postulates and if they are even right.