Purpose: In this investigation you will conduct an experiment & grow two species of paramecium, alone & together. You will then compare the growth curves of the population of each species. Question

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opulation Biology- Paramecium (35 pts.)

Names: _________________________ and ________________________ Date: ___________Period: __

Purpose: In this investigation you will conduct an experiment & grow two species of paramecium, alone & together. You will then compare the growth curves of the population of each species.

Question: How does competition affect population growth?

Click on the information button @ the bottom of the screen. Record at least three facts about paramecium. (3 pts.)

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What is carrying capacity? (1)

How will you know when the carrying capacity is reached in the environment?(1)

What is competitive exclusion?(2)

Define limiting factor. (1)

NOW…. Go back to the procedure (box located on the left of the screen) & answer the following questions.

What is the food for the bacteria? _________________________(1)
What is the food for the paramecium? _____________________(1)
Do the two species of paramecium prey on each other? __________(1)
Make a hypothesis about how you think the two species of Paramecium will grow alone. Will growth be steady, fast, declining…P. caudatum or P. Aurelia?(2)

Make a hypothesis about how the two species of Paramecium will grow TOGETHER. Which paramecium will out compete the other?(2)

Read the directions!!!! Follow the procedure & complete the experiment. Skip any mention of completing the science journal!!!! Place 2 squirts of P. caudatum in test tube 1. Place 2 squirts of P. aurelia in test tube 2. In test tube 3, place one squirt of

P. caudatum and P. aurelia.
Data Table for Paramecium Growth… (10 pts)

You need to multiply # of paramecium by 2.

	TEST TUBE 1	TEST TUBE 2	TEST TUBE 3
	P. caudatum grown alone, cells/mL	P. aurelia grown alone, cells/mL	P. caudatum grown in mixed culture, cells/mL	P. aurelia grown in mixed culture, cells/mL
Day 0
Day 2
Day 4
Day 6
Day 8
Day 10
Day 12
Day 14
Day 16

Why did you have to multiply the number of paramecium by the number 2? (1)

What day is the Paramecium caudatum population reaching its carrying capacity in test tube 1? How did you know? (2)

What day is the Paramecium aurelia population reaching its carrying capacity in test tube 2? How did you know? (2)

Explain the differences in the population growth patterns of the two Paramecium species when growing together in test tube 3. (2)

What is a limiting factor in test tube 3? (1)

Explain how this experiment demonstrates that no two species can occupy the same niche….competitive exclusion! (2)