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Dissolved Oxygen  0 2 4 6 8 10 12 14 16 18 # of fish observed 0 1 3 10 12 13 15 10 12...

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kristenrenah | Student, Undergraduate | eNotes Newbie

Posted September 8, 2011 at 9:12 AM via web

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Dissolved Oxygen  0 2 4 6 8 10 12 14 16 18

# of fish observed 0 1 3 10 12 13 15 10 12 13


. Develop a hypothesis relating to the amount of dissolved oxygen measured in the water sample and the number of fish observed in the body of water.

3. What would your experimental approach be to test this hypothesis?

4. What are the independent and dependent variables?

5. What would be your control?

6. What type of graph would be appropriate for this data set? Why?

7. Graph the data from the table above.

8. Interpret the data from the graph made in Question 7.



1 Answer | Add Yours

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aimeefarnum | High School Teacher | (Level 2) Adjunct Educator

Posted September 10, 2011 at 5:00 AM (Answer #1)

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Hypothesis:  If you increase the amount of dissolved oxygen in the water, then more fish will be observed because fish need oxygen for cellular respiration.

Independent Variable:  Amount of dissolved oxygen

Dependent Variable:  Number of fish observed

Control variables:  same temperature, body of water, amount of light, same amount of fish food

Control experiment:  Water from the body of water without altering the oxygen.

Experiment:  Create a series of aquariums with different levels of dissolved oxygen (0ppm, 2ppm, 4ppm, 6ppm, 8ppm, 10ppm) including one take designed to have the exact same conditions as the pond the minnows come from.  Place 100 minnows in each tank.  Take data daily on number of fish in each tank.  Proceed for a week. Remove dead fish from the tank.

Data analysis:  Dissolved oxygen is necessary for fish to perform cellular respiration.  In this experiment it was determined that these fish thrive in water sources that are between 6-14 ppm with the most fish found in 12 ppm at 15 fish.  The least amount of fish were found in water sources with 0 ppm which is otherwise known as anoxic conditions.

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