Bug Writeup

Ishrat Hafiz0837-040

Ishrat Hafiz000837-040Vincer – 2/3

IB Internal Assessment: The Effect of Temperature on Respiration of Armadillidium vulgare

Research Question: What is the Effect of Temperature on the Respiration of Armadillidium vulgare?

Background Information:

Armadillidium vulgare, or the pill bug, is of the kingdom Animalia, phylum Arthropoda, class Malacostraca, order Isopoda, and family Armadillidiidae. It is the most common species of isopod experimented upon in the United States. They are found in the United States and Europe. Their natural habitats are moist, dark places, such as beneath rocks or bark (Philip, 416). They are common household pests. The pill bug has a striated shell around its body, like a crustacean, and is a dark brown-black. When threatened, pill bugs roll into a small ball. This defense mechanism goes along with gathering in small groups.

Armadillidium vulgare is cold blooded, and as such, its metabolic rate is affected by its surrounding temperature (Warburg, 51). Metabolism in organisms is the process by which food is converted to energy. This process happens through oxidative respiration in Armadillidium vulgare, and involves the breakdown of sugars using oxygen, which in turn produces water, energy in ATP form, and carbon dioxide. The respiration rate can be measured by the amount of carbon dioxide an organism produces.

Hypothesis: As the temperature surrounding Armadillidium vulgare increases, the rate of respiration of the organisms will increase.

Variables:

Units RangeIndependent

VariableTemperature (± 2º C) Degree Celsius (º C) 0 - 40

Dependent Variable Respiration Rateppm (parts per

million)432 – 587

Independent VariablesTemperature (±2º C) 0º C 10º C 20º C* 30º C 40º C

Number of Trials 5 5 5 5 5* indicates control

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Constant Variable Units Method Reason

Pill Bugs (Armadillidium

vulgare)number

The same number (5) and the same type of pill bugs were

used in every trial throughout the experiment.

Since the experiment was contingent on the respiration rate of pill

bugs, the same number of pillbugs were used in each

trial. The physiological

characteristics of the pill bug could also

affect the respiration rate, and therefore, the appearance of the pill

bug had to be as similar as possible.

Water mL

500 mL of water was used to achieve each temperature and then poured into the fish tank

the pill bugs were put in.

The same volume of water was used so that

the bugs were submerged to the same degree, and

would feel the effect of the temperature to

the same depth.

Logger Pro and Carbon Dioxide Probe

ppm

Five pill bugs were put in the same chamber and their

respiration rate was measured with the same software and

probe.

The same software, probe, and gas

chamber were used throughout the

experiment to limit systematic error.

Thermometer º C

The same thermometer was used to measure the

temperature of each level of the independent variable.

The same thermometer was used

to limit systematic error.

Time Seconds

The pill bugs were kept in each temperature environment for 5 minutes using a timer, and then

immediately transferred into the carbon dioxide gas chamber for 5 seconds recorded by the

Logger Pro software.

Keeping the crickets in the environment for

more or less time would change their

respiration rate.

Environment N/A

All of the pill bugs were put in the same fishbowl with the

same amount of solution in the same beaker.

Exposure to different environments would change the pill bugs’

reception.

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Materials:

Items Quantity

Fish Bowl 1Vernier Lab Pro, Logger Pro, CO2 Gas Probe 1

Ice 2 L500 mL Beaker 2600 mL Beaker 1

Pill Bugs 25Stir Rod 1

Heat Plate 1Thermometer (± 2º C) 1

Paper Towel Roll 1Distilled Water Plenty

Timer 1Laptop/computer 1

Plastic Spoon 1

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Pictures of Lab Set Up:

Vernier Logger Pro was connected to the laptop, and the carbon dioxide probe was connected to the Lab Pro interface. Since temperature was the independent variable, 5 different solutions had to be raised or lowered to a certain temperature. The solution was then poured into the fish tank, into which the 600 mL beaker containing the pill bugs was placed (shown in Figure 1). After 5 minutes, the pill pugs were immediately transferred to the respiration chamber, and their respiration rate was measured (shown in Figure 2).

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600 mL beaker

Fish tank

Water

Carbon Dioxide probe

Laptop

250 mL respiration chamber

Armadillidium vulgare

Figure 1

Figure 2


Procedure:

1. Assemble Vernier Logger Pro and the carbon dioxide probe. Attach them to the laptop. Calibrate the carbon dioxide probe.

2. Fill a 500 mL beaker with ice. Place a thermometer in the beaker and wait for the temperature to reach 0º C.

3. Once the desired temperature has been reached, pour the ice solution into the fish bowl.4. Retrieve five pill bugs from the pill bug container. They should be approximately the

same size and shape.5. Set the timer for 5 minutes. Place the 5 pill bugs into the tall 600 mL beaker, and place

them inside the solution- filled fish tank. Start the timer.6. Upon the conclusion of 5 minutes, immediately transfer the pill bugs to the respiration

250 mL respiration chamber with the plastic spoon. 7. Plug the CO2 probe into the respiration chamber and collect the respiration rate of the pill

bugs every second for 5 seconds.8. The average respiration rate of the 5 seconds will be recorded in the data table for each

trial. Repeat for 5 trials. 9. Retrieve another group of 5 pill bugs and replace the old group in the pill bug container

so the previously used pill bugs can return to their normal habitat.10. Fill the 500 mL beaker with water. Place 4 ice cubes and the thermometer in the beaker

and wait for the temperature to reach 10 º C.11. Repeat steps 3-9.12. Fill the 500 mL beaker with water. Add 1 ice cube, and place the thermometer in the

beaker. Wait until the temperature reaches 20 º C.13. Repeat steps 3-9.14. Fill the 500 mL beaker with water. Place on a hot plate and turn on the setting to 4. Place

the thermometer in the beaker while the water is heating. When the temperature reaches 30 º C, remove the beaker from the hot plate.

15. Repeat steps 3-9 with the heated solution.16. Fill the 500 mL beaker with water. Place on the hot plate and turn to the setting to 5.

Place the thermometer in the beaker until the water heats to 40 º C.17. Repeat steps 3-9.

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Method for Collecting Data:

Measuring the IV: The thermometer measured the temperature of the water for the five levels at 0 º C, 10 º C, 20 º C, 30 º C, and 40 º C. Then, each solution of water was poured into the fish tank.

Measuring the DV: 5 Armadillidium vulgare were put into a beaker within the fish tank, then taken out after a timer measured 5 minutes and transferred to the respiration chamber. The carbon dioxide probe was put on the low setting (0-1000 ppm). Data (ppm) was taken for 5 seconds, and the average ppm of the five seconds was collected.

Table 1:

The Effect of Temperature on Respiration of Armadillidium vulgare

Temperature (±2 º C)

Respiration Rate (± 1 ppm)

Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 MeanStandard Deviation

0 º C 446 437 432 440 434 438 5.4910 º C 465 452 456 460 463 459 5.2620 º C* 478 480 477 479 478 478 1.1430 º C 523 530 525 547 534 531 9.5240 º C 581 585 587 574 578 581 5.24

*indicates control

Explanation of Table 1: The independent variable being tested for the experiment was temperature, which began at 0 º C, and was then increased by 10 º C until 40 º C was reached. This, there were 5 levels of investigation. 20 º C was the control of the independent variable because it is closest to room temperature. The dependent variable was the respiration rate measured in ppm of the organism Armadillidium vulgare, which indicated the amount of energy produced as a result of metabolic activity. A pattern becomes apparent—the higher the temperature, the greater the average respiration rate. The range of the data was from 432 ppm to 587 ppm. The increase of the range can be explained by the corresponding increasing temperatures. Because the respiration rates for each trial were different to varying extents, the mean and the standard deviation was taken. The mean was taken by adding all of the data for each of the 5 trials of a particular level, and then dividing by 5. This was done so that the standard deviation could be found, which describes the precision of the investigation by measuring how spread apart the data is.

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Qualitative Data: As the temperature increased, Armadillidium vulgare moved around the bottom of the beaker more quickly (shown in Figure 3). During the colder temperatures, the pill bugs either rolled up or huddled close to one another (shown in Figure 4).

Uncertainty and Error: The uncertainty for the independent variable, the temperature, was ± 2 º C . This accounts for any human errors which may have occurred in determining the exact temperature of the water. The respiration values also had an uncertainty of 1 ppm, which covers the possibility of error in the carbon dioxide probe.

Worked Points:

Mean: The average respiration rate in ppm for 20 º C is (478+ 480 + 477 + 479 + 478)/5 = 478 ppm.

Standard Deviation:

σ=√∑ (X−μ)2

n

The method used to find the standard deviation of data for 20 º C is:

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Figure 3 Figure 4


1. Find the mean (478)2. Subtract the mean from each value (ex: 480 – 478= 2.00)3. Square each value obtained from Step 24. Add the values obtained from Step 35. Divide by one less than the total number of trials (4, in this situation)6. Square root the answer from Step 5 – This is the standard deviation (1.14).

Graph 1:

0 5 10 15 20 25 30 35 40 450

100

200

300

400

500

600

700

The Effect of Temperature on Resperation Rate

TEMPERATURE IN DEGREES CELSIUS (±2ºC)

RESP

IRAT

ION

RAT

E IN

PPM

(±1

ppm

)

Explanation: The average rate of respiration was calculated from the original data to represent of the whole data set. The respiration rates of Armadillidium vulgare increase as temperature increases, suggesting a positive direct relationship between temperature and respiration rate. The error bars for the respiration rate are set at ± 1 ppm, to indicate the uncertainty for carbon dioxide probe values. The error bars for the temperature are set to ±2º C to account for any errors with the thermometer, or human errors while interpreting the temperature reading.

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Conclusion:

This investigation’s purpose was to test the effect temperature on the respiration rate of the organism Armadillidium vulgare , known as the pill bug. The pill bug is a cold- blooded animal (Warburg 51), and therefore its surrounding temperature directly affects its bodily functions. Cold- blooded organisms need heat from their environs to regulate their own temperature and metabolism. If the internal body temperature is high, then metabolism is quicker and more energy is produced by the breakdown of sugar, which occurs through respiration. For this reason, the hypothesis stated that higher surrounding temperatures would result in higher respiration rates.

Water and ice were mixed together to create solutions of colder temperatures of 0, 10, and 20 º C. Then, water was heated upon a heating plate until it reached temperatures of 30 and 40 º C all of which were measured by a thermometer. Each solution was poured into a fish bowl, in which 5 pill bugs were placed within a beaker. After 5 minutes steeped in the solution, the organisms were removed and their respiration rate was recorded using a carbon dioxide gas probe. Quantitatively, as the temperature increased in degrees Celsius, the respiration rate on average increased as well. The range of the data was from 432-587 ppm. In the colder temperatures, the pill bugs tended to move more slowly and huddled together, meaning their metabolic rates were slower as they sought warmth, and therefore resulting in the low respiration rates. Comparatively, the pill bugs moved around very quickly in hotter temperatures, meaning their metabolic processes were higher, which explains their greater respiration rate.

The collected data supports the hypothesis, because as temperature increased, the respiration rate did as well. As the temperature increased in increments of 10 º C from 0 º C to 40 º C, the respiration rate increased from an average of 432 ppm to 587 ppm. The graph shows this positive trend. The upwards- sloping relationship shows that a relationship between temperature and respiration rate can be inferred, n that cold- blooded organisms have an increased respiration rate and therefore increased metabolism in warmer temperatures.

The experimentation with living organisms made this lab liable for error. While the propagation of error with the instruments was an issue, since there was an uncertainty of ±2 º C, the more important flaw was the behavior of the pill bugs. They had a tendency to roll up for defense whenever they were dropped in new beakers, which may have spurred internal survival mechanisms that had some effect on their respiration rate. The bugs were also not of the exact same size and shape, and were being used for different experiments by other students, which could have altered them from their regular state in some way. The main source of error relying on the unstable behavior of the bugs decreases the accuracy of the collected results.

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Getting rid of the error would entail that exactly the same size and shape of pill bug be used in the exact same relaxed state. This would have resulted in less error because the data collected would be objective in terms of new bugs that hadn’t been exposed to prior experimentation, and that were already undergoing massive changes in surroundings. Had a different and fresh group of Armadillidium vulgare from their natural habitat been used, the conditions would have simulated their natural habitat, leading to a more accurate investigation of how temperature affects these organisms in nature. Furthermore, a temperature probe could have been used to garner the exact temperature, rather a thermometer with a much larger uncertainty. Following such improvements, the experiment can simulate the situation of cold- blooded animals in nature, particularly in places with volatile weather. More importantly, with today’s global issues of pollution which are leading to rising temperature, further research can be conducted on precisely how much quicker our metabolism and respiration rate would work. It also has implications to scientific problems, such as the disappearance of dinosaurs, since as cold- blooded organisms, massive changes in the early atmosphere may have affected their metabolic processes necessary for life.

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Bibliography

Philip, P. 1988. The New Encyclopedia Britanica. Fifteenth Edition. Page 416

Warburg, M. 1993. Evolutionary Biology of Land Isopods. Springer-Verlag, NY. Pages 50-53.

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