FIG. 1.8

Can living organisms arise from nonliving matter?

BACKGROUND Until the 1600s, many people believed that rotting meat spontaneously generates maggots (fly larvae).

HYPOTHESIS Francesco Redi hypothesized that maggots come only from flies and are not spontaneously generated.

EXPERIMENT Redi used three jars containing meat. One jar was left open; one was covered with gauze; one was sealed with a cap.

RESULTS

CONCLUSION The presence of maggots in the open jar and the absence of maggots in the gauze-covered and sealed jars supported the hypothesis that maggots come from flies and allowed Redi to reject the hypothesis that maggots are spontaneously generated.

FOLLOW-UP WORK Redi’s experiment argued against the idea of spontaneous generation for insects. However, it was unclear whether his results could be extended to microbes. Applying the scientific method, Louis Pasteur used a similar approach about 200 years later to investigate this question (see Fig. 1.9).