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Lab report on rolly pollys brought into our class for us to examin....

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Roly Poly Lab Report AP Biology Sameen Khan Kayln Alston

Introduction: In the experiment tested our main question / goal was “What type of water will the pill bugs prefer?’. Pill Bugs go by many names such as: roly-poly, woodlouse, armadillo bug, potato bug. . Pill bugs are commonly found in damp environments like compost, piles of leaves or under logs. They are crustaceans but can spend their entire lives on land, unlike lobsters, crabs, shrimp and other members of the crustacean family. According to Northern State University, there are approximately 4,000 species of pill bugs, which are also commonly called sowbugs, woodlice or rollie-pollies.Rollie Pollies ability to curl up distinguishes the pill bug from another close relative, the sowbug. Since they are actually the only crustaceans that spend their lives on land, they use trachea-like lungs to breathe, If salt was sprinkled on a pill bug, their lungs would dry out and they would proceed to die. Which makes me come to the hypothesis that The rolly pollies would prefer the normal tap water over the salt water. Methods: To materials we used to test this experiment were, 1 behavior Chamber, 11 pill bugs in a cup, 2 pieces of filter paper ,2 cups of tap water ,salt and a timer. Once the materials are gathered Place a piece of filter paper in both compartments of the behavior chamber.Take a cup of tap water and ½ spoon of salt in to form salt water. Wet the left side of the behavior chamber with 10 drops of tap water.Wet the right side of the behavior chamber with 10 drops of salt water. Place all 11 rolly pollies in the middle of the 2 compartments of the behavior chamber. Record all of your observations of the movements/ locations of the pill bugs every 30 seconds. Results: The pill bugs moved at a slow speed making it seem like it was hard for them to decide what compartment of the behavior chamber to choose. Starting off with 0-0 on both compartments didn't last long, 10 out of the 11 bugs headed to the tap water side, while 1 of the pill bugs went to the salt water. For the first 4 trials everything was going as expected, more pill bugs on the tap water side. Suddenly came a twist in the experiment, the salt water compartment contained more pill bugs then the tap water compartment.On the 6th trail everything went back to normal, you know more pill bugs in the tap water compartment.Until we reached trial number 8 and 9, there was no movement for 60 seconds made by the pill bugs for trail 8 and 9. Data Collection: Figure 1: Time (in

# Number of Pill Bugs in tap water.

# Number of Pill Bugs in saltwater.

seconds) 0

0

0

30

10

1

60

9

2

90

7

4

120

5

6

150

6

5

180

10

1

210

9

2

240

9

2

270

8

3

300

10

1

Figure 2:

After all the data we collected using the graph and table we ran a chi square test. A chi square test is “commonly used for testing relationships between categorical variables”www.statisticssolutions.com. My partner and I used this test to see if there was a correlation in

the amount of pill bugs in tap water and saltwater. Figure 3: # of Pill bugs in tap water

# of pill bugs in saltwater

Total

Observed

83

27

110

Expected

55

55

110

Difference

28

-28

Difference Squared

784

784

( O-E)^2 / E

14.3

14.3

X^2= e(O-E)^2/E

28.6

Discussion/ Analysis: Our results conclude that the pill bugs do prefer the tap water over the saltwater. According to our graph the tap water pill bugs immediately increased in trail 1, but started decreasing at a slow rate meanwhile the saltwater pill bugs started increasing until trial 6 .After trail 6 the data went back to supporting our hypothesis as the tap water pill bugs increased.The hypothesis we expected “ The rolly pollies would prefer the normal tap water over the salt water” was supported by the data and the observations made. In the future we can test mineral water with tap water since mineral water has somewhat of salt. We could also test raw water, distilled water, carbonated water, and bottled water with tap water seeing which one is more prefered. This data can be used in real life by helping someone that is keeping the pill bugs as a pet or in their homes. It could let them know what type of environment the pill bugs like to be in. Which can also lead to many new ways to do this experiment can be improved by adding different types of pill bugs seeing if they all react the same way or you can test different trials at different room temperatures seeing if that plays a factor in the pill bugs movements. I believe the experiment turned out how I thought it would be because Pill bugs live in moist locations. They are found under damp objects and not often will you find salt water on the street most commonly it would be rain water or water leaked from somewhere. As seen in figure 1 the table shows the number of pill bugs in each compartment of the behavior chamber per 30 seconds. Figure 2 shows a visual display of the data from the table on a graph which can be more easier to understand/interpret. Figure 2 shows the rapid increase and decrease of both compartments and shows a similarity between both of the compartments meaning there was almost the same pill bugs in each of the 2 compartments. It also shows the graph being

stable and not moving on trail 8 and 9 for both compartments. In figure 3 the chi squared table was shown, To see if that observed distribution was due to chance. If your chi-square calculated value is greater than the chi-square critical value, then you reject your null hypothesis. If your chi-square calculated value is less than the chi-square critical value, then you accept it. Since our null hypothesis was greater we rejected it. References: 1. Animal behavior lab given by Ms. Stiles 2. Lab Partner : Kayln Alston...