EVOLUTION
THE ORIGIN OF LIFE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Needham heated his broth while Spallanzani did not.
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Spallanzani heated his broth while Needham did not.
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Needham sealed his flasks tightly while Spallanzani did not.
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Spallanzani sealed his flasks tightly while Needham did not.
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Detailed explanation-1: -As in Needham’s experiment, broth in sealed jars and unsealed jars was infused with plant and animal matter. Spallanzani’s results contradicted the findings of Needham: Heated but sealed flasks remained clear, without any signs of spontaneous growth, unless the flasks were subsequently opened to the air.
Detailed explanation-2: -Explain why the experiments of Needham and Spallanzani yielded in different results even though they used similar methodologies. Both boiled broths to test the theory of spontaneous generation, but Needham didn’t boil his long enough.
Detailed explanation-3: -Needham’s broth experiment had two fundamental flaws. First, his boiling time was not sufficient to kill all microbes. Second, his flasks were left open as they cooled, and exposure to the air could cause microbial contamination.
Detailed explanation-4: -Spontaneous generation is the theory that living organisms may be created from non-living matter, as shown by the presence of life in supposedly sterile conditions. Biogenesis is the theory that all living matter originates from other living matter. This distinguishes between abiogenesis and spontaneous generation.
Detailed explanation-5: -Spallanzani found significant errors in the experiments conducted by Needham and, after trying several variations on them, disproved the theory of spontaneous generation.