-
Francesco Redi
• debunked Spontaneous Generation
• experiment- put decaying meat in jars to see if flies grew from the meat
• sealed jar- no flies
• open jar- flies inside
• covered with cheese cloth- flies sitting outside on top -
John Needham
• claimed to have disproved Redi's experiment
• boiled broth in sealed flasks- after several days, organisms grew
• problems with experiment- didn't boil broth long enough for it to be sterile -
Lazzaro Spallanzani
• redid Needham's experiment - disproved Spontaneous Generation
• boiled broth for proper amount of time to kill organisms
• sealed container didn't grow organisms, open one did
• people still didn't believe him- said organisms couldn't grow in his experiment because he didn't allow any air in -
Louis Pasteur
• disproved spontaneous generation
• proved Redi was correct - created theory of Biogenesis
• Biogenesis- living things come only from living things
• boiled broth in S-necked flasks-- air could get through, but organisms would get stuck in neck
• after over a year, no organisms grew-- only grew when he tilted flasks so that broth contacted org.s in S-neck
• proved biogenesis- living things can come only from other living things -
Alexander Oparin
• created hypothesis- early Earth was made of gases (ammonia, hydrogen, methane, water vapor) that combined with oceans to form a "primordial soup"
• amino acids formed from soup, and life evolved from amino acids -
Stanley Miller and Harold Urey
• independently performed experiments that proved Oparin's hypothesis
• heated water (simulated oceans + Earth hot from volcanic activity), gases pass through electricity (lightning), then condensed it back to water and found amino acids in it
