For many centeries people believed in spontaneous generation instead of what we now know today as biogenesis. Spontaneuous generation was the assumption that life can come from nonliving things. It was believed that mice could come from corn, maggots from rotting meat, fish from mud etc. Multiple experiments were conducted and the theory was disproven. In 1668 an italian scientist by the name of Francesco Redi designed and created an experiment to test spontaneous generation. Redi placed fresh meat in two different jars. One jar left open, the other was covered with a cloth. Days later, he checked the jars to see what occured. The jar the was open contained maggots and the jar that was covered by cloth had nothing. He believed he had sucessfully solved the sponaneous generation debate. 77 years after Redi's experiment that disproved spontaneous generation John Needham, an English clergyman, designed an experiment to challenge Redi's findings. He placed gravy into a bottle, then proceeded to heat the bottle to a high enough temperature that it would kill anything living inside. Then he sealed the bottle. When he checked the broth a few days later he found microorganisms. He believed he created life from nonliving materials, which he proceeded to broadcast. In reality he did not heat the bottle enough to kill everything inside. In 1768 spontaneous generation was again challenged. Instead of an Italian scientist this time it wa an Italian Priest. Lazzaro Spallanzani believed that the microorganisms in John's experiment entered the broth through air before it was sealed. To test this he modified John's experiment. He placed broth in two seperate bottles. Boiling them both. He sealed one of
THE PARADIGM SHIFT OF BIOGENESIS