Animal Behavior

Animal Behavior: Response to Environmental Variables
Background/Abstract:
Ethology is the science based on animal behavior. Many animal behaviors involve the movement of animals within its own environment. Inherited traits are traits that an animal is born with and learned behaviors are what an animal learns on its own to adapt to the surroundings. Innate behaviors like breathing and learned behaviors are talking or walking. Pill bugs are the animals we observed in the lab. Pill bugs are a family of woodlice and are a crustacean in the isopoda order. Most people know them as roly polies. They can roll into a ball which they use as a defense mechanism against predators. They often do this when they feel a vibration or pressure applied to them. Pill bugs are also decomposers and break down leftovers, feces, and so forth.
In the experiment we observed the behavior of the pill bugs and how they react to a side with dirt and a side with no dirt. The dependent variable was the number of pill bugs on each side and the independent variable was the dirt in the experiment. The dependent is the variable being measured in an experiment whereas the independent variable is what is tested in the experiment. The control in the group is the dry side. The constants kept throughout the experiment were the time length and the number of pill bugs. The bugs decided on the side with dirt so the hypothesis was rejected. They prefer the moisture in the dirt, so they chose that side rather than the side with nothing.
Question: Do pill bugs prefer the side with dirt or no dirt?
Hypothesis: Pill bugs do not prefer dirt or no dirt.
List of Materials:
-Dirt
-10 Pill bugs
-Choice Chambers
-water
-filter paper
-brush
-timer
Procedure:
Step 1: Add dirt to one side of the choice chamber and leave the other side empty.
Step 2: Add five pill bugs to each side of the choice chamber.
Step 3: Count the pill bugs on each side of the chamber every 30 seconds for 10 minutes.
Step 4: Analyze the data of the pill bugs.
Data Tables and Graphs:
Dirt 5 9 2 9 9 10 9 9 8 9 8 9 10 8 8 9 9 9 10 9
No Dirt 5 1 8 1 1 0 1 1 2 1 2 1 0 2 2 1 1 1 0 1 Analysis of Data: The pill bugs preferred the side with dirt rather than the sire with no dirt. The observed amount overall for the side with no soil was 32 and the side with dirt was 168. The expected amount would be 100 and 100. If you subtract the observed and expected you would get negative 68 for the side without dirt and positive 68 for the side with dirt. Once you square those two numbers you get 4,624 and once you divide that number by the expected amount you get 46.24%. You add those two numbers and get 92.48% overall. I would have to reject my hypothesis because there is a significant difference.

Conclusion/results: The pill bugs preferred the side with dirt instead of the side with no dirt. Compared to the hypothesis the bugs like to be around dirt more so we have to reject our hypothesis. The bugs had a choice of randomly moving where they would like to and could not be predicted unless tested. When tested they preferred one side over the other. Based on the data they preferred the side with dirt because they decompose components in the dirt.

Sources of error/possible modification: Placing five pill bugs on either side of the choice chamber was a problem, so next time it would be better to place a barrier between the chambers so an even amount of bugs can be on either side. This would give better data because it would be an easier way to observe which side is really preferred. There seemed to be an error when collecting the data towards the beginning which caused the line graph to be out of place in one area. Making sure to collect the correct data is a key issue to correct.