Francesco Redi’s Spontaneous Generation experiments. By: Luke Arroyo-Clark

9th grade Living Environment Project

Goal: pretend you are Francesco Redi and explain the popular belief in society at the time, explain your (Redi’s) beliefs, and a conclusion.


       Most people believe that small animals animals like flies, wasps, cicadas, spiders, ants, scorpions, and all the other grubs of the land and air are just spontaneously created from rotting meat, dirt, plants, and grain. Most people believe that mice come from piles of grain and wet cloths and flies and maggots come from rotting meat and that wasps are randomly generated from plant tissue and many other small animals that are randomly generated from the earth. 

       I believe that small animals are not spontaneously generated, but instead that all living things on this earth are the result of the real and true seeds of plants and animals themselves who conserve their species by means of their own.


I chose to experiment on how maggots come from rotten meat. I first put a piece of meat in a sterile jar for the control. I let it sit there in the jar for for two weeks. After two weeks I noticed maggots and flies emerging from the now rotten meat. 

As the independent variable I put a piece of meat in a sterile jar, then placed a piece of screen on top of the jar and let the meat sit in the jar with the screen on top for two weeks. After two weeks I noticed that flies were laying their eggs on the screen. I began to suspect that the flies payed their eggs based on the smell of the rotten meat rather than spontaneously generating in the meat.

As the dependant variable I chose to put piece of meat in a sterile jar and put a cork over the jar so the flies could not smell the meat. I left the meat in the jar for two weeks and when I came back their were no flies at all. Inside the meat or outside the jar. 


My conclusion is that flies and other animals do not spontaneously generate but instead are the seeds of plants and animals themselves who preserve their species by their own means and that meat and grass and all other putrefied or putrefiable things play no role in insect generation. Instead, those rotten and putrid things only provide a suitable place to nest which animals are drawn to at their time of birth.