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What is Spontaneous Generation?. The idea that organisms originate directly from non living matter
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1. Where Do Living Things Come From? Ms. Spadaro
3. How Did This Happen? Every year the Nile River flooded leaving behind nutrient rich
soil that enables people to
grow that year’s crops.
However, along with the muddy
soil, large numbers of frogs
appeared that weren’t around in
drier times.
4. How Did This Happen? Conclusion:
It was perfectly obvious to the people back then that muddy soil gave rise to the frogs.
5. How Did This Happen? In many parts of Europe, medieval farmers stored grain in barns with thatched roofs. As a roof aged it started to leak. This could lead to spoiled or moldy grain, and of course, there were lots of mice around.
6. How Did This Happen? Conclusion:
It was obvious that the mice came from the moldy grain.
7. Hello, Francesco Redi Italian Doctor most well-known for his experiment in 1668 which is regarded as a one of the first steps in refuting spontaneous generation.
9. Redi’s Experiment Jar-1
Left open Maggots developed
Flies were observed laying eggs on the meat in the open jar
Jar-2
Covered with netting Maggots appeared on the netting
Flies were observed laying eggs on the netting
Jar-3
Sealed No maggots developed
10. Lazzaro Spallanzani Lazzaro Spallanzani was an Italian naturalist who also attempted to disprove the Theory of Spontaneous Generation, almost one hundred years after Francesco Redi.
With the invention of microscopes after Redi's death, scientists were able to see tiny organisms that they could not see with the naked eye.
In the late 1700's, Lazzaro Spallanzani tried to disprove this by performing a controlled experiment with broth.
12. Louis Pasteur Louis Pasteur was a French chemist who finally disproved the Theory of Spontaneous Generation in the mid 1800's. Louis Pasteur performed the same type of experiment as Spallanzani, except both of his flasks allowed air to enter
14.
Are you ready?
15. Quick Quiz The flies could smell the meat that was
16. Answers in the open container only
In the open container and in the cloth covered container
In the airtight container
17. Quick Quiz The flies could not smell the meat that was
18. Answers in the open container only
In the open container and in the cloth covered container
In the airtight container
19. Quick Quiz The flies laid their eggs only on the meat in the jar that was
20. Answers Open
Closed
Cloth Covered
21. Quick Quiz Maggots develop only where
22. Answers The meat was decaying
The flies had laid their eggs
The flies had not laid their eggs
23. Quick Quiz What did Spallanzani and Pasteur do differently than Redi?
24. Answers They used scientific equipment
They boiled their broth
They made sure the room they did the experiment in was airtight
25. Quick Quiz How was Pasteur’s experiment different from Spallanzani?
26. Answers A. He used only chemicals from his laboratory
B. He boiled his broth
C. He allowed air into his containers
27. Quick Quiz Life comes only from matter that is
28. Answers Dead
Living
Nonliving