Roly Poly Lab

Pillbug “Roly-Poly” Behavior LaB ? Purpose: The purpose of this lab is to observe the behavior of the Armadillium vulgare (roly- poly bug), as well as hypothesize whether it will be attracted to, repelled by, or unresponsive to certain substances. Methods 1. Observing the pillbug: examine the pillbug’s shell and body, shell shape, color, texture, number of legs, number of antennae, motion, speed, and sex after close examination. 2. Formulate hypotheses: choose substances (powders and liquids) and suggest whether the pillbug will be attracted to, repelled by, or unresponsive to each substance. . Perform an experiment: using a control, test the pillbug’s reaction to the substances 4. Compare with classmates: determine whether classmates had similar results when testing the same substance. Data Collected ? The pill bugs have 7 pairs of legs with 14 overlapping plates. Oval-shaped like a “pill”. One pair of antennae. Black with lighter spots. The pillbugs climb over each other. The male pillbugs are bigger and darker 3 female pillbugs. Male plays dead on his back when tampered with. The pillbugs roll into a ball for safety. Uropods at the end of abdomen. Legs move in a quick wave-like motion. ?? ? 1. As the pillbug moves around in the beaker, the movement of the legs is very quick and fluid; similar to that of a “wave”. 2. To protect itself from predators, the pillbug rolls itself into an armored ball. Similarly, the pillbug uses its hard exoskeleton as a way to protect itself from the elements. Their long antennae allow for them to locate food and their shorter legs in the front help to bring the closer food to their mouths. Lastly, the pillbug’s multiple legs allows for it to interact with the environment. 3. When allowed to crawl on my hand, the pillbug moved quickly in a zig-zag motion. I could feel the pillbug as it made it’s way up my arm. After close examination, I later discovered that the pillbug was able to cling to my skin because of it’s hook-like tips on it’s legs. 4. When the beaker is slightly tilted, the pillbugs prefer to move forward toward the top of the beaker. Next, we measured the speed and distance of each pillbug. The results can be seen in the table below. The next step was to formulate hypotheses about the pillbug’s reaction to common powders and liquids.  The next part of the lab was to then test the pillbug’s reaction to the chosen substances and determine whether or not the hypotheses in Table 1. 3 were supported in this experiment. The control in this experiment was water. The final procedure in the lab was to compare our results with the results of our classmates who tested the same substances. The results can be seen below in Table 1. 5. ? Key: + = towards; - = repelled ; 0 = no reaction Summary/Conclusions This experiment demonstrates that pillbugs prefer a wet environment to a dry one. Through our data, we have concluded that our hypothesis, “if the pillbug is exposed to water, then it will be responsive and move toward it” , is correct. Even so, we also hypothesized that, “if the pillbug is exposed to milk, then it will be responsive and move toward it”; this, however, was proven incorrect after we performed the experiment. On the other hand, several other groups also tested the pillbug’s reaction to milk and found that the pillbug moves toward it. To better improve this experiment, we would make sure that there is no trace of water in the path of the pillbugs when we test the other substances. Factors that could have possibly altered the results in the experiment would be the age and gender of the pillbugs. PILLBUG “ROLY-POLY” LAB REVIEW QUESTIONS: A theory is more comprehensive than a conclusion. A hypothesis is a tentative explanation of observed phenomena. Data is the information scientists collect while doing experiments and making observations. After experiments and observations comes the conclusion. A control is a sample that foes through all the steps of an experiment and does not contain the factor being tested. Yes, data can prove a hypothesis to be true. Conclusion Scientific Theory A pillbug has 14 body divisions If a pillbug curls into a ball, it can be concluded that it feels threatened. Pillbugs that back away from a substance are repelled by the substance. THOUGHT QUESTIONS: 1. A scientific theory is a concept that ties together many varied conclusions into a generalized statement. 2. It is important to use one substance at a time when testing a pillbug’s reaction because in this experiment we are trying to determine whether or not the pillbug is repelled by, attracted to, or unresponsive to a specific substance. If you use more than one substance at a time, it will not determine whether the pillbug is attracted to, repelled by, or unresponsive to a substance, especially if the pillbug is already headed towards the direction of a substance. 3. No, the scientific method cannot explain all observations. In order for the scientific method to explain all observations, it must be able to answer a question about something that can be measured. The question: Do pillbugs have a color preference ? cannot be tested by the scientific method. METRIC MEASUREMENTS & MICROSCOPY REVIEW QUESTIONS: 1. 11 mm equals 1. 1 cm 2. 50 mm equals 0. 95 m 3. 2. 1 liters equals 2100 ml 4. 122°F equals 50° C 5. 4. 100 mg equals 0. 0041 g THOUGHT QUESTIONS: 19. Locating an object is more difficult if you start with the high-power objective rather than the low-power because the high-power objective is used to get a closer study of an object/specimen, whereas the low-power objective is used to quickly scan and LOCATE something smaller in a large area. 20. The advantages that the metric system provides over the English units of measure is that all conversions, whether for volume, mass(weight), or length, can be in units of ten. 21. Scanning power objective allows you to observe the greatest number of cells within the field of view. Natural State Rolled into a Ball Observation: Pillbug’s External Anatomy Observation: Pillbug’s Motion Table 1. 2 Pillbug Speed Pillbug Millimeters Traveled Time(sec) Average Speed(mm/sec) 1. 11. 1 mm 10 1. 11 mm/sec 2. 60 mm 10 6 mm/sec 3. 00 mm 10 20 mm/sec 4. 40 mm 10 4 mm/sec Table 1. 3 Hypotheses About Pillbug’s Reaction to Common Powders and Liquids Hypothesis About How Pillbug Substance Tested Will Respond to Substance Reasoning for Hypothesis 1. Milk If the pillbug is exposed to milk, then it will be responsive and move toward it. Moist 2. Water If the pillbug is exposed to water, then it will be responsive and move toward it. Moist 3. Sugar If the pillbug is exposed to sugar, then it will be unresponsive and move away from it. Dry 4. Flour If the pillbug is exposed to flour then it will be unresponsive and move away from it Dry Table 1. 4 Pillbug’s Reaction to Common Substances Substance Tested Pillbug’s Reaction Hypothesis Supported? 1. Milk Unresponsive NO 2. Water Responsive YES 3. Sugar Unresponsive YES 4. Flour Unresponsive YES Table 1. 5 Class Results

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