Origin of Life

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Pasteur's Experiment - Step 1

S-shaped Flask

Filled with broth

The special shaped was intended to trap any dust particles containing bacteria

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Pasteur's Experiment - Step 2

Flasks boiled

Microbes Killed

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Pasteur's Experiment - Step 3

Flask left at various locations

Did not turn cloudy

Microbes not found

Notice the dust that collected in the neck of the flask

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Pasteur's Experimental Results

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Pasteur’s S-shaped flask kept microbes out but let air in.

Proved microbes only come from other microbes (life from life) - biogenesis

The Theory of Biogenesis

Figure 1.3

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Review

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1668: Francisco Redi filled six jars with decaying meat.

Evidence Pro and Con

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1745: John Needham put boiled nutrient broth into covered flasks.

Evidence Pro and Con

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1765: Lazzaro Spallanzani boiled nutrient solutions in flasks.

Evidence Pro and Con

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1861: Louis Pasteur demonstrated that microorganisms are present in the air.

Evidence Pro and Con

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