History of Spontaneous Generation

By iris.yip
  • 380 BCE

    Aristotle Proposes the Idea of Spontaneous Generation

    Aristotle Proposes the Idea of Spontaneous Generation
    Aristotle first 'synthesized' the idea of spontaneous generation by gathering the different claims by past philosophers.He published a book titled 'History of Animals'. In the book, he theorized that certain forms of life could come from/be produced by non-living things. This was where the idea of 'spontaneous generation' first came to be.

  • Redi's Experiment

    Redi's Experiment
    Francesco Redi opposed the idea of Spontaneous Generation through his experiment of placing fresh meat in two separate jars-- one sealed, and one left open. Days later, the meat in the sealed jar showed no sign of maggots, while the unsealed one did. He concluded that maggots came from fly eggs, and not the meat itself.

  • Needham's Gravy Experiment

    Needham's Gravy Experiment
    Needham opposed Redi's experiment by conducting his own experiment. He placed gravy/broth in a sealed bottle ​and heated it in order to kill whatever could be alive inside the substance. Days later, he reported that there were signs of life within the gravy. However, this was because he didn't actually heat the bottle well enough and thus, didn't manage to kill all the microbes.

  • Spallanzani (Gravy Experiment 2.0)

    Spallanzani (Gravy Experiment 2.0)
    Lazzaro Spallanzani conducted an alternative gravy experiment, as he thought that maybe Needham didn't kill everything in the bottle. He boiled two bottles of broth and sealed one, and left the other one unsealed. Days later, the unsealed one showed no sign of life while the sealed one did. However, many scientists didn't believe this was accountable because there was a theory that said spontaneous generation required oxygen, which wasn't possible in the sealed container.

  • Louis Pasteur Ends Debate

    Louis Pasteur Ends Debate
    With the help of special S-curved necks that would prevent objects from getting in with gravity, he successfully disproved Spontaneous Generation as no signs of life appeared in the broth even after a whole year. From this, he concluded that life forms came from the contamination of the things in the air.

  • John Tyndall, Explanation

    Tyndall found certain organisms are heat resistant, succeeding Pasteur's results as well as explaining Needham's.