EVIDENCES AGAINST THE THEORY OF SPONTANEOUS GENERATION: Theory of spontaneous generation was criticized by Lazzaro spallanzani, Francisco redi and Louis Pasteur. These great scientists performed well designed scientific experiments to disprove the theory of spontaneous generations.

1. Redi’s experiment: Francisco redi did conclusive and well designed experiment to disapprove the theory of spontaneous generation. He placed meat and fishes in 3 separate jars. Jar No. 1 was left open, No. 2 was covered with gauze and the third one was covered with paper. The meat/fishes decayed in all three jars and attracted flies. In Jar No. 1, flies entered and layed eggs which eventually gave birth new larvae. Whereas in Jar No. 2, flies couldn’t be able to enter and no larve was found inside the jar. But flies laid eggs on gauze that produced larvae. This has conclusively proves that organisms arise from the pre-existed organism rather than non-living matter.

2. Spallanzani’s Experiment: The experimental setup is given in the Figure 3.3. In the designed experiment to test the validity of theory of spontaneous generation. In this experiment, spallanzani has prepared animal or vegetable broth and boiled them for several hours and then either remained open or sealed immigately. These broth remained free from microorganism growth. He concluded that high temperature boiling had killed all microorganisms and in the absence of microorganism life could not appear. The broth left open or exposing of sealed broth shows growth of microorganisms.      

Figure 3.2 : Redi’s Experiment to disprove the theory of abiogenesis.