Paramecium Lab
(Virtual Lab: Population Biology)
http://glencoe.mcgraw-hill.com/sites/dl/free/0078757134/383928/BL_04.html
Background: A paramecium is a single celled organism that you can see with a microscope.
Purpose: You will grow two species of the protozoan Paramecium, alone and together. You
will then compare growth curves of the populations of each species.
Question: How will the growth of the two populations of Paramecium change if they are
grown together?
Hypothesis: (answer the question above) _____________________________________
______________________________________________________________________
IV: ____________________________________________________________________
DV: ___________________________________________________________________
Procedure: This lab has instructions on the left hand. You do not need to click on the
Journal button since you will be entering data in your data table below. Briefly explain the
procedures (how did you test your hypothesis) __________________________________
_______________________________________________________________________
_______________________________________________________________________
Data Table
P. aurelia grown
alone, cells/mL
Day O
Day 2
Day 4
Day 6
Day 8
Day 10
Day 12
Day 14
Day 16
P. caudatum
grown alone,
cells/mL
P. aurelia grown
in mixed culture,
cells/ mL
P. caudatum
grown in mixed
culture, cells/mL
Data Analysis: Create a graph to show how the populations of paramecium changed over 16
days, each grown alone and then together. You will need to include: a title, labels for the x
axis and y axis, 4 lines (each a different color), a key, and correct units.
__________________________________
Key:
P. aurelia grown alone=
P. caudatum grown alone=
P. aurelia grown together=
P. caudatum grown together=
Conclusion Questions:
1. On what day did the Paramecium aurelia population reach the carrying capacity of
the environment? How do you know?
2. On what day did the Paramecium caudatum population reach the carrying capacity of
the environment when it was grown alone? How do you know?
3. Explain the differences in the population growth patterns of the two Paramecium
species when grown alone. What does this tell you about how Paramecium aurelia
uses available resources?
4. Describe what happened when the Paramecium populations were mixed in the same
test tube.
5. Explain how this experiment demonstrates that no two species can occupy the same
niche.