Ch 1 Flashcards
Antoni van Leeuwenhoek (1632-1723)
Dutch fabric merchant, began making simple microscopes. Not the first to invent microscopes, but first to look at living samples. Discovered “wee animalcules” aka microorganisms and came up with 5 categories. Biggest contribution: royal society of London.
What were the five categories of microorganism described by Leeuwenhoek and what didn’t he find and why?
Included prokaryotes, small animals, fungi, algae, and Protozoa. He couldn’t see viruses because he used a light microscope which they were too small to see with.
Carolus Linnaeus (1707-1778)
Swedish botanist, develop system of taxonomy (grouping things together based on similarities). genus and specific epithet=binomial naming system uses two names of general and specific of Latin origin.
What are the three domains of life?
Bacteria (prokaryotes) , Archaea (prokaryotes) and Eukarya(eukaryotes).
Acellular microbes and why are they not a part of the three domains?
Viruses, virions , and prions. Not part of the domains because they aren’t alive.
What four questions were scientists trying to answer during the “Golden Age” of Microbiology?
- Is spontaneous generation of life possible?
- What causes fermentation?
- What causes diseases?
- How can we prevent infections/diseases?
What is spontaneous generation? (A-biogenesis)
Getting life from nonliving material.
Who first proposed the idea of spontaneous generation and where did they believe that life came from?
Aristotle.
He thought H2O and soil created life
Ex. Nile river dry out = no life vs water in river = frogs
Who first doubted spontaneous generation?
Francesco Redi
Francesco redi experiment 1 (late 1660)
Doubted spontaneous generation, tested this by putting meat in a jar and sealed out air to prove that flies came from other flies, and not from the meat and air. People complained that he was excluding air and he needed to include air to truly test it.
Francesco Redi experiment 2
(What he did and his conclusion)
During the second experiment, Redi covered the meat with gauze, and observed flies, dropping eggs on top, but they never got in. His conclusion- for larger animals life comes from life (biogenesis).
John Tuberville Needham (1740s)
Boiled meat and plants for short amount of time and kept the jar closed with a cork, which resulted in spontaneous generation of microbes. People wondered, whether or not the cork was actually considered sterile.
Lazaro Spallanzani (1799)
Copied needham’s experiment, but instead fused the glass closed and boiled the beef and plants for a longer period of time. Results - no growth, meaning that he came to the conclusion that spontaneous generation does not happen with microbes.
Why did Spallanzi believe that needhams experiment conclusion was wrong?
He didn’t boil the water long enough, used a cork instead of sealing flask, and that abiogenesis doesn’t occur for microbes.
What did critics say was wrong with Spallanzani’s experiment?
Since he sealed his flask closed, it meant that there was no air which means no growth and that the prolonged heat killed the “life force.”
Louis Pasteur (1822-1895)
Settled the debate by using a swan-neck flask, which allowed for steam/air to move in and out of flask as it was boiling, but prevented dust from getting inside, as it would rest on the bend. Conclusion- biogenesis.
What is the scientific method?
Observation, followed by questions in order to generate a hypothesis. In order to test hypothesis, experiment is then created and observed. Then the hypothesis is either accepted, rejected or modified and tested again.
What’s the difference between a hypothesis and a theory?
A hypothesis is an assumption (educated guess) made before research and can be tested in order to prove it correct/incorrect where as a theory has already been tested and has data to back it.
