Spontaneous Generation - Scientific Experiments Flashcards

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1
Q

Name 4 scientists who studied scientific generation.

A

Francisco Redi, John Needham, Lazzaro Spallanzani, and Louis Pasteur

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2
Q

When was Redi’s experiment?

A

1668

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3
Q

What was the problem that Redi studied?

A

Do flies produce maggots?

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4
Q

What was Redi’s hypothesis?

A

If maggots appear on meat after a couple of days, then flies produce them, because they lay eggs too small for humans to see.

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5
Q

Describe Redi’s experiment.

A

He placed jars with meat out and covered half with gauze, effectively keeping flies out.

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6
Q

What was Redi’s independent variable?

A

The gauze on the jars

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7
Q

What was Redi’s dependent variable?

A

Maggot appearance

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8
Q

What was Redi’s control group?

A

The jars without gauze

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9
Q

What was Redi’s experimental group?

A

The jars with gauze

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10
Q

What were Redi’s results?

A

He discovered that the meat exposed to flies was covered in maggots, but the other meat did not.

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11
Q

What were Redi’s conclusions?

A

He concluded that flies lay microscopic eggs on meat, thus producing maggots.

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12
Q

When was Needham’s experiment?

A

Mid 1700’s

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13
Q

What problem did Needham study?

A

Spontaneous generation can occur under the right circumstances.

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14
Q

What was Needham’s hypothesis?

A

If I heat gravy until all life may have died, then “animalcules” will spontaneously generate.

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15
Q

Describe Needham’s experiment.

A

He heated a sealed container of gravy, assuming that he killed off all life. He looked inside to find out whether or not life was there.

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16
Q

What was Needham’s independent variable?

A

Heat (of the gravy)

17
Q

What was Needham’s dependent variable?

A

Presence of ‘animalcules’

18
Q

Did Needham have a control group?

A

No

19
Q

What were Needham’s results?

A

There was life in the gravy.

20
Q

What was Needham’ conclusion?

A

Life can spontaneously generate.

21
Q

What problem did Spallanzani investigate?

A

Does the gravy need to be hotter (than Needham’s) to kill the ‘animalcules?’

22
Q

What was Spallanzani’s hypothesis?

A

If I heat up gravy and kill all of the ‘animalcules,’ then no more will form, because spontaneous generation is false.

23
Q

Describe Spallanzani’s experiment.

A

He boiled two sets of glasses of gravy and sealed half. He made sure that no animalcules were left and waited for more.

24
Q

What was Spallanzani’s manipulated variable?

A

The seal on the glasses

25
Q

What was Spallanzani’s responding variable?

A

The presence of ‘animalcules’

26
Q

What was Spallanzani’s control group?

A

The unsealed flasks

27
Q

What was Spallanzani’s experimental group?

A

The sealed flasks.

28
Q

What were Spallanzani’s results?

A

The sealed jars had no life. The open jars were teeming with life.

29
Q

What was Spallanzani’s conclusion?

A

The nonliving gravy cannot produce the living ‘animalcules.’

30
Q

When was Pasteur’s experiment?

A

1800’s

31
Q

What problem did Pasteur investigate?

A

Do air and dust particles influence the growth of microorganisms?

32
Q

What was Pasteur’s hypothesis?

A

If air is left in the broth because of the curvy-necked glass, then microorganisms will not appear because spontaneous generation is false.

33
Q

Describe Pasteur’s experiment.

A

He made a curvy-necked glass and left it filled with broth for a year. Then he took the neck off.

34
Q

What was Pasteur’s manipulated variable?

A

Curved neck on the glass

35
Q

What was Pasteur’s responding variable?

A

Appearance of life

36
Q

What was Pasteur’s control group?

A

Non-curved-neck glass

37
Q

What was Pasteur’s experimental group?

A

Curved-neck glass

38
Q

What were Pasteur’s results?

A

There were no microorganisms for a year in the curvy-necked glass, but once the neck was broken off, it teemed with life.

39
Q

What was Pasteur’s conclusion?

A

Things do not spontaneously generate.