Early Thoughts on Life
1. What was Aristotle's idea about how life arose called?
2. What is another name for spontaneous generation?
3. Explain spontaneous generation of life.
4. How long did the idea of abiogenesis or spontaneous generation last?
5. The idea of abiogenesis lasted so long because, instead of testing their ideas, people based their beliefs on what?
6. Were their observations tested?
7. Did they use the scientific method for their observations?
Examples of Spontaneous Generation
8. What observation about new life did Egyptians make when the Nile River flooded each year?
9. What observation about new life did Medieval farmers make when they stored their grain each year?
10. The English people centuries ago, threw their garbage and sewage out on the streets. What observation about new life did these people make?
11. This practice led to a plague that killed many Europeans. What was this plague called and what carried the disease organism?
12.Before refrigerators, large slabs of meat were hung after being purchased. What observation about new life was made from this practice?
13. People believed so strongly in abiogenesis that they had recipes for making living things. Name two organisms that had accepted recipes.
Disproving Spontaneous Generation
14. Francesco ____________ was an early scientists who conducted experiments to try and disprove spontaneous generation.
15. What was Redi's hypothesis?
16. Explain how Redi tried to prove this.
17. What were the results Redi found in the closed jars & why?
18. What were the results in the open jars?
19. How did maggots appear in the open jars?
20. Complete this table summarizing Redi's experiment:
|Evidence Against Spontaneous Generation|
|Gauze Covered jar|
21. Redi's experiment disproved spontaneous generation for _____________ organisms.
Use of the Scientific Method
22. Did Francesco Redi use the scientific method in his experiment?
23. What served as the control in Redi's experiment?
24. What jars served as the experimental groups?
25. What was Redi's conclusion?
Disproving Spontaneous Generation of Microbes
26. Anton Van _______________ made one of the first simple microscopes.
27. Leeuwenhoek called the living things he saw in pond water ______________.
28. By the end of the 19th century, these organisms were known as ______________.
29. John _____________ did experiments with microorganisms growing in broths.
30. Needham believed there was a __________ __________ present in nonliving substances like air.
31. Why were bacteria able to grow in Needham's soups?
32. What could have been done to the broths to kill the bacteria already present?
33. What scientists repeated this experiment but with boiled broth?
34. After boiling, what did Spallanzani do to the tops of the bottles? how did this help?
35. Critics of Spallanzani's experiment said there was not enough _______ for the bacteria to survive and that boiling had destroyed the _________ __________.
The Theory Changes
36. What did the Paris Academy of Science do in 1860 to solve the problem?
37.Who won the prize?
38. What was Pasteur's experimental hypothesis?
39. What was the shape of Pasteur's flasks? Include a sketch.
40. What was the special S-shaped neck intended to do?
41. Did Pasteur boil the broth in his flasks? Why?
42. The flasks were left at ___________ locations.
43. Did the broth change cloudy because microbes were growing in it?
44. What was visible in the neck of the flask after collecting there?
45. Once the S-shaped stem was broken off the top of the flasks, what happened to the broth and why?
46. Pasteur's S-shaped flasks kept ___________ out but let ______ inside.
47. Pasteur's experiment proved that living things only come from other _________ ___________.
48. What is the name of Pasteur's theory?
49. Where did the maggots come from in Redi's experiment?
50. What was the purpose of the sealed jars?
51. Redi was trying to disprove - spontaneous generation or biogenesis?
52. Where did the microbes come from in Needham's broth?
53. Needham & Spallanzani were trying to disprove - spontaneous generation or biogenesis?
54.Who proved biogenesis?