Population Biology- Bacteria Vs. Protozoa

Name ______Period______

Population Biology- Bacteria vs. Protozoa

Directions:

1) Go to the following website to begin your lab:

2) Read the purpose, objectives, and procedure of the lab with your partner. After you are done reading, write a summary of what you will be doing in this lab here…

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3) The first step of the lab tells you to read the information about paramecium, population growth, and competition. Read the information and answer the following questions.

a) What is exponential growth?

b) What is a limiting factor? Give 2 examples of limiting factors.

c) Define carrying capacity:

4) The next part of the lab instructs you to put specimens in each test tube. You should place ONLY one specimen in the first two test tubes and then combine them in the last one. Answer the first JOURNAL question below.

Journal question 1: “Make a hypothesis about how you think the two species of Paramecium will grow alone and how they will grow when they are grown together.” (2 different hypotheses-don’t forget “if…then”)

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5) Continue reading the instructions and going through the virtual lab. When you get to the part where it asks you to count cells, use the paper copy of the data table to record your data, NOT the virtual table. **Make sure you read the part that talks about cells/ml, and you calculate the number of cells correctly**

6) When you are done collecting all of your data for all 16 days, construct a graph. Your graph MUST have a title, labels, a proper scale, and a key.

7) When you have finished your graph, complete the remaining Journal questions.

Journal Questions:

2) Explain how you tested your hypothesis.

3) On what day did the Paramecium caudatum population reach the carrying capacity of the environment when it was grown alone? How do you know?

4) On what day did the Paramecium aurelia population reach the carrying capacity of the environment? How do you know?

5) Explain the differences in the population growth patterns of the two Paramecium species. What does this tell you about how Paramecium aurelia uses available resources?

6) Describe what happened when the Paramecium populations were mixed in the same test tube. Do the results support the principle of competitive exclusion?

7) Explain how this experiment demonstrates that no two species can occupy the same niche.

Title:
P. aurelia grown alone (cells/ml) / P. caudatum grown alone (cells/ml) / P. aurelia grown in mixed culture (cells/ml) / P. caudatum grown in mixed culture (cells/ml)
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Day 4
Day 6
Day 8
Day 10
Day 12
Day 14
Day 16

Data Table