LAB ACTIVITY: HOW DOES TEMPERATURE AFFECT THE RATE OF RESPIRATION IN FISH?

Background: In this laboratory activity we will change the temperature of the water that a fish is in and determine what impact, if any, this has on the breathing (respiration) rate of the fish. Counting gill cover movements is a way to calculate respiration rates in fish. Fish breathe by taking water in through the mouth and forcing it over the gills when the mouth closes. An oxygen-carbon dioxide exchange occurs. Then the operculum opens to allow the carbon dioxide-rich water to exit. By counting gill cover movements, students are getting an idea of a fishes' response to an ecological change.Respiration rates will typically increase as dissolved oxygen concentration decreases. An increase in water temperature means a decrease in dissolved oxygen available for the fish to breathe from the water.

Materials:

Goldfish

Tank Water

Tupperware Bowl

Medium beaker, 600ml

Thermometer

Timer or clock

Ice

Hot water

Procedure:

1.Bring all materials to your lab table.

2.Bring the empty beaker to the aquarium containing the goldfish & fill it ~ 2/3 full with aquarium water.

3.Use a thermometer to measure the temperature of the water in your medium beaker (fish bowl.)

4.The starting temperature needs to be 20 °C. If needed, add warm water until the water is 20 °C.

5.Place a 600ml beaker with the fish into the Tupperware bowl

6.Determine baseline data:

  1. Take the temperature of the water in the beaker & record on the data table
  2. Allow your goldfish some time to calm down (this may take several minutes)
  3. Count respirations (by looking at either the opening/closing of the mouth or the opercula) for one minute & record on the data table on the back of this page.

DO NOT add iceor hot water directly to the goldfish beaker!

7.Determine warm water experimental data:

  1. Fill an empty beaker with warm water from the water bath at the front of the room.
  2. Place your fish beaker in the plastic bowl & add warm water to the tupperware bowl; thiswillslowly increase the temperature inside the beaker.
  3. Once the temperature inside the fish beaker has increased ~5 degrees Celsius count respirations for one minute. Record data in the data table.
  4. Repeat, making sure to not go above 30°C

8.Determine cold water experimental data:

  1. Pour out any water from your Tupperware bowl & fill it approximately 1/3 full with tap water.

9.Add 1-2 pieces of ice to slowly into the Tupperware bowl to lower the temperature of the water until the temperature inside the fish beaker has decreased ~5 degrees Celsius from the original temperature (20°C)

10.Count the number of times your goldfish breathes in one minute. RECORD in the data table.

11.Repeat making sure not to go below 10°C and RECORD in the data table

12.Clean up all materials & place your gold fish in the “rest” tank to recover.

Data:

200
195
190
185
180
175
170
165
160
155
150
145
140
135
130
125
120
115
110
105
100
95
90
85
80
75
70
65
60
55
50
45
40
10 / 11 / 12 / 13 / 14 / 15 / 16 / 17 / 18 / 19 / 20 / 21 / 22 / 23 / 24 / 25 / 26 / 27 / 28 / 29 / 30

Figure 1: Observations of fish with in different temperatures

Temperature / Your fish / Fish 2 / Fish 3 / Average (Your fish + Fish 2 + Fish 3) ÷ 3
20 °Croom temp
15 °Ccool
10 °Ccolder
25 °Cwarm
30 °Cwarmer

Figure 2: Observations - Line Graph

Plot separate lines to show the average breathing rate of fish at each of the different temperatures

Label each line with a different color

Add a title that includes the dependent and independent variables

Title ______

`

Temperature °C

Prelab----Answer the following questions before completing the lab procedure:

1.What is the purpose of this lab activity? ______

2.Are fish warm-blooded or cold-blooded animals? ______

3.How do external temperatures affect cold-blooded animals? ______

4.How do external temperatures affect warm-blooded animals?______

5.What do you think will happen as you increase/decrease the temperature of your goldfish’s water? ______

6.Restate what you said above as a hypothesis? (If…. Then… Because)

______

7.What is the independent variable (the factor that you are controlling)?______

8.What is the dependent variable (the factor that changes with the independent variable’s changes) ______

9.What are the variables we have to keep as constants (factors that are the same for everyone) ______

10.What is our control group data (normal environment for the fish)?______

ANSWER THE FOLLOWING QUESTIONS AFTER COMPLETING THE LAB PROCEDURE

11.Based on your data what is the relationship between respiration and temperature in fish?

12.Based on the graph data, what do you think is the relationship between fish behavior and temperature?

13.Does the data in the graph support or contradict your hypothesis?

14.What other factors (besides temperature) may have affected the rate?

15.What do you think happens to the activity of fish in cold climates during the winter months?

16.Why do you think cold-blooded animals, like the goldfish, change their breathing rate when the surrounding temperature changes?

17.How do you think this might explain the results of the experiment?

Observations: (Restate each of your observations; be sure to use numbers AND units from data you collected!!)

______

Conclusion: (ONE sentence about whether your hypothesis was or was not correct based on the data)

______

Analysis(2-3 Paragraphs): Use your data to summarize the effect of temperature of on fish

Support any statements you make with data from your graph or data table

Be sure to state at least one source of error experiments are not perfect and we can always improve!!

State what you would do differently.

______

______

Three More Questions (What you still want to know)

  1. ______
  2. ______
  3. ______

Extra Credit--- Design an experiment that will test how a fish's respiration rate is affected by light. Explain your design. You may wish to draw a picture of your set-up. Include how you will change the environment and what you will be measuring.