HLR AP Biology – Laboratory 10 Alternate – “Respiration Rate and Temperature”
Laboratory 10 Alternate:
Respiration Rate and Temperature
AKA “The Goldfish Lab!”
Introduction: Ectothermic animals do not maintain a constant body temperature; their body
temperature tends to be near that of the environment. In these animals, the
metabolic rate, which is affected by temperature, varies over a wide range. In
ectothermic animals, there is a direct relationship between the rate of many
physiological activities and environmental temperature. The rate of metabolism in
these animals increases as environmental temperatures increase from
approximately 5°C to 35°C. Increasing the temperature by 10°C results in an
approximate doubling of the metabolic rate. That is why a snake or lizard can
hardly move when it is cold but becomes quite active after warming in the sun.
In fishes, the exchange of respiratory gases occurs as water flows across the gills.
The rate of oxygen uptake can be measured indirectly by observing the rate at which
the operculum, or gill flap, or the mouth opens and closes. Changes in
environmental temperature should affect the rate of respiration in a fish.
Materials:
Medium-Sized Goldfish
Crushed Ice
Small fish net
Thermometer
Pipettes
Two Large Beakers
(1000 mL)
Hotplate
Stopwatch
Procedure:
You will be placing your fish into water of 4 different temperatures, beginning with
the warmest. The temperatures will be approximately 25°C, 20°C, 15°C, and 10°C.
These temperature values are arbitrary. Do not spend valuable time attempting to
get these exact temperatures. Simply record the exact temperature at which each
respiratory rate is determined. While your fish is acclimating to one temperature of
water, you will be preparing a second beaker. Go to the analysis section of this lab.
Record your hypothesis about the effects of various temperatures on the respiration
rate of a fish there.
1. Fill a 1000 mL beaker ab0ut two-thirds full with aquarium water at room
temperature. Measure and record the temperature of the water.
2. Fill another 1000 mL beaker with slightly less water than the first, and then
add heated water to this beaker to raise its temperature approximately 5°C
above the first beaker.
3. Place a goldfish in the second (warm) beaker. Allow the fish to acclimate for
3 minutes. During this time make two practice counts of mouth or opercular
openings per fifteen seconds. You will use this to determine the respiration
rate.
-1-
HLR AP Biology – Laboratory 10 Alternate – “Respiration Rate and Temperature”
4. Count the number of times the fish opens and closes its mouth or operculum
in 15 seconds. Repeat for a total of three measurements. Calculate the
average respiration rate per minute.
5. Carefully move your fish to the beaker with room temperature water. Record
the water temperature. While you are waiting for the fish to acclimate to the
new beaker, add ice chips to the warm beaker until its water temperature is
5°C below the room temperature beaker. Repeat the counting procedure.
6. Move the goldfish to the cooler beaker. While you are waiting for the fish to
acclimate to the new beaker, add ice chips to the room temperature beaker
until its water temperature is about 10°C below room temperature. Repeat
the counting procedure. (You should now have data for 5°C above room
temperature, room temperature, 5°C below room temperature and 10°C
below room temperature.)
7. At the conclusion of your data collection, gradually add some warm water to
the final beaker to bring its temperature to the approximate temperature of
the aquarium. Return the fish to the aquarium and recycle the aquarium
water.
8. Graph temperature versus average respiration rate (respirations/min).
Data Table:
Temperature
Respirations/15 sec Trial
1
2
3
Average
Respirations/min
(Warm)
(Room)
(Cold)
(Very Cold)
Analysis:
1. Formulate a hypothesis about the affects of various temperatures on the
respiratory rate of a fish.
_____________________________________________________
_____________________________________________________
_____________________________________________________
-2-
HLR AP Biology – Laboratory 10 Alternate – “Respiration Rate and Temperature”
2. What kind of pattern is evident from your graph? Do the data in the graph
support or refute your hypothesis?
_____________________________________________________
_____________________________________________________
_____________________________________________________
3. Why does temperature affect respiration rate in ectotherms?
_____________________________________________________
_____________________________________________________
_____________________________________________________
4. At what temperature does your graph indicate that the fish’s respiratory rate
would equal zero?
_____________________________________________________
5. Why is it important to wait a few minutes after placing your fish in the new
temperature water before counting the respiratory rate?
_____________________________________________________
_____________________________________________________
_____________________________________________________
6. What is the experimental advantage of starting with the warmest
temperature and working gradually in the other direction, instead of
skipping around to different temperatures?
_____________________________________________________
_____________________________________________________
_____________________________________________________
7. How would you expect temperature to affect the fish’s need for food and oxygen?
On what do you base your assumptions?
_____________________________________________________
_____________________________________________________
_____________________________________________________
-3-
HLR AP Biology – Laboratory 10 Alternate – “Respiration Rate and Temperature”
8. What happens to the activity of fishes in cold climates during the winter months?
_____________________________________________________
_____________________________________________________
_____________________________________________________
9. What do you think is the effect of environmental temperature on the metabolic rate
of a homoiotherm, such as man, within a “comfortable” range of temperatures that is
neither near freezing nor very hot? Why?
_____________________________________________________
_____________________________________________________
_____________________________________________________
10. How might an ectothermic organism’s behavior help it regulate its temperature?
Give at least 3 specific examples.
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
-4-
HLR AP Biology – Laboratory 10 Alternate – “Respiration Rate and Temperature”
The independent variable: ______________________________
Use this to label the horizontal (x) axis.
The dependent variable:
______________________________
Use this to label the vertical (y) axis.
Title: ________________________________________________________
-5-