8/17/2016 Francesco Redi-1668 John Needham-1745 Strong opponent of spontaneous generation Strong believer of spontaneous generation Demonstrated that maggots did not arise from decaying corpses 。Was Redi wrong? Flask is open OPEN MAGGOTS GAUZE Chicken broth boiled Microbes grov Broth clears What gave rise to the maggots?What was the purpose of the sealed jars?Spontaneous generation or biogenesis? What gave rise to the microorganisms?Spontaneous generation or biogenesis? Lazzaro Spallanzani-1765 Louis Pasteur-1861 .Strong opponent of spontaneous generation Strong opponent of spontaneous generation Hypothesized:microbes from the air had entered Rudolf Virchow(1858)established the concept of the flask biogenesis but had no proof Pasteur resolved the issue and confirmed biogenesis Microbes originated from the air and not the broth Loter,vi force 66 air goes in Chicken broth boilec Broth clears Basis of aseptic techniques-prevent contamination of unwanted microorganisms 88/17/2016 8 Francesco Redi - 1668 Strong opponent of spontaneous generation Demonstrated that maggots did not arise from decaying corpses What gave rise to the maggots? What was the purpose of the sealed jars? Spontaneous generation or biogenesis? John Needham- 1745 Strong believer of spontaneous generation Spontaneous generation can occur under the right conditions Was Redi wrong? What gave rise to the microorganisms? Spontaneous generation or biogenesis? Chicken broth boiled Flask is open Broth clears Microbes grow Lazzaro Spallanzani- 1765 Strong opponent of spontaneous generation Hypothesized: microbes from the air had entered the flask Critics of his work stated that the “vital force” from the air was kept out Later, vital force was said to be oxygen Chicken broth boiled Flask is sealed Broth clears Broth remains clear Louis Pasteur - 1861 Strong opponent of spontaneous generation Rudolf Virchow (1858) established the concept of biogenesis but had no proof Pasteur resolved the issue and confirmed biogenesis Microbes originated from the air and not the broth air goes in but microbes are kept out Basis of aseptic techniques – prevent contamination of unwanted microorganisms