Redi’s Experiment Interesting
The cell theory states that cells can come only from other living cells.
Facts About
Since living things are made up of cells, living things must come from
The cell theory states that cells can come only from other living cells. Since living things are made up of cells, Living
other living things. You might be thinking, “Of course! Everybody knows
living things must come that!”
from other things. You had
might be thinking, Things
Yet,
yearsliving ago, many
people
a different
idea. “Of course! Everybody knows that!” Yet, years ago, many people had a different idea. About 300 years ago, the Italian scientist Francesco Redi wondered
where maggots—small, wormlike organisms—came from. The popular
About 300 years ago, the Italian scientist Francesco Redi wondered where maggots—small, wormlike belief at the time was that rotting meat turned into maggots. This idea,
organisms—came from. The popular belief at the time was that rotting meat turned into maggots. This idea, that living things could come from nonliving material, was called
that living things could spontaneous
come from ngeneration.
onliving m
aterial, was called spontaneous generation. Redi designed an Redi designed an experiment to test this belief.
experiment to test this He
belief. He meat
placed eat into tofwo groups of jars. One group of jars was left open, and the placed
intom
two
groups
jars.
One group
of jars
was
left open,
other was sealed tightly. Diagram shows what Redi observed. and
the other1 was
sealed
tightly.
Diagram
1 shows what Redi observed.
Events
in typical
open jar:
Events
in typical
sealed jar:
Day 1
Day 2
Day 4
Day 8
Flies
Meat
Flies land on
meat, attracted
by rotting odor
Maggots appear
Most of meat
on rotting
consumed; maggots
meat
develop into flies
Day 1
Day 2
Day 4
Day 8
Meat
Meat begins
to rot; no
flies near jar
No maggots
on rotting
meat
Most of meat still
present; no maggots
or flies inside jar
Redi noted that no maggots appeared on the rotting meat in the sealed
Diagram 1. Redi’s first e
xperiment: d
rawings s
how e
vents i
n (
top) a
t
ypical o
pen j
ar; (
bottom) a
typical sealed jar. iagram 1. not
Redi’s
first experiment:
drawings that
showRedi’s
eventsexperiment
in (top) a had
jars. DHowever,
everyone
was convinced
typical spontaneous
open jar; (bottom)
a typical sealed
disproved
generation.
Some jar.
people claimed that fresh air
Redi noted that no maggots appeared on the rotting meat in the sealed jars. However, not everyone was was needed for spontaneous generation to occur. Therefore, Redi
convinced that Redi’s experiment had disproved spontaneous generation. Some people claimed that fresh air performed gaeneration second experiment.
He covered
thepjars
with fine
netting.experiment. He was needed for spontaneous to occur. Therefore, Redi erformed a second The
netting
allowed
airallowed into thefresh jars but
flies
from
covered the jars with fine netting. The nfresh
etting air iprevented
nto the jars but prevented flies from entering entering
and
landing
on
the
meat.
Diagram
2
shows
what
Redi
observed
and landing on the meat. Diagram 2 shows what Redi observed in his second experiment. in his second experiment.
Day 1
Netting lets fresh
air into jar
Chapter 9
Levels of Organization
Events in
Transparency Master 288
typical jar
covered by
netting:
Day 2
Flies
Day 4
Maggots
Day 8
Dead
maggots
Copyright © by Amsco School Publications, Inc.
Meat
Flies land on
Maggots appear Maggots on netting
netting, attracted on netting; no
are dead; most of
by rotting meat
maggots on
meat remains; no
rotting meat
maggots or flies
inside jar
. Redi’s second experiment. Diagram 2. Redi’sDiagram second 2experiment.
Study both diagrams and both
then diagrams
answer the following questions on the nquestions:
ext page: Study
and
then answer
the following
Questions
Questions 1. Based on Redi’s experiments, where do the maggots come from? 2. What is spontaneous generation? 3. What conclusion about spontaneous generation can you draw from these experiments? 4. Why did Redi perform a second experiment? 5. What is an independent (manipulated) variable? 6. What is a dependent (responding) variable? 7. What was the independent (manipulated) variable in this experiment? 8. What was the dependent (responding) variable in this experiment? 9. Identify 3 different constants in this experiment. 10. What is a controlled experiment? 11. Why is this considered a controlled experiment?