Animal Behavior Lab
Introduction
Name:
Period:
Ethology is the study of animal behavior. Behavior is an animal's response to sensory input, and falls into two basic categories: learned and innate (inherited). Orientation behaviors place the animal in its most favorable environment. In taxis, the animal moves toward or away from a stimulus. Taxis is often exhibited when the stimulus is light, heat, moisture, sound, or chemicals. Kinesis is a movement that is random and does not result in orientation with respect to a stimulus. If an organism responds to bright light by moving away, that is a taxis. If an animal responds to bright light by random movements in all directions, that is defined as kinesis.
In this lab, you will be working with terrestrial isopods commonly known as pill bugs, sow bugs, or roly-polies. These organisms are members of the Phylum Arthropoda, Class Crustacea, which also includes shrimp and crabs. Most members of this group respire through gills.
Directions:
You are a scientist studying the pill bug behavior. You want to look at how individual variables can affect the pill bug. Possibilities study topics include moisture, background color, temperature, environment type, light vs. dark, pH level, or substances that might be used as food.
You must design and carry out an experiment to test 2 different variables. Your first variable must be moisture. Your group can choose the second variable.
You will create a lab report, following the AP biology lab report guidelines and rubric, showing your design, results, and analysis.
Background: Conduct background observation / research of pill bugs
Based on what you have read about pill bug behavior, prior to the lab, search for pill bugs at your home or at school. If you cannot find any, look up information or videos about them online. When you have found some individuals, observe them as unobtrusively as possible (try not to disturb them after you have located them). Notes the behaviors you observe, and estimated time duration for each behavior. Make notes on their general appearance, movements about the area, and interactions with each other. Notice if they seem to prefer one area over another, if they keep moving, settle down or move sporadically. When the pill bugs are disturbed, what is their response?
Summarize what you learn and observe in a background paragraph. Use this information to help you form a hypothesis.
Before the Lab: You must come to lab with your background, hypothesis, and procedures done!
1. With your group, decide on the second variable.
2. Conduct background research (may need to be done at home or with internet)
3. Develop a hypothesis. (you may include both variables in one hypothesis or have 2 separate hypothesis)
4. Design your experiment: including a list of materials, variables, and procedures you will use
5. Design your data table and graphs.
a. Think about how long you will run each trial for and at what time intervals you will record the location of pill bugs. You will also need a way to come up with average results across trials (3 trial minimum) or a time you want to use in your statistical analysis (the last recorded time is usually the best, once the bugs have settled in).
During and After the lab:
6. Set up and run your experiment: Make sure to record number of trials, sample size, and account for all variables. Also make any needed alterations to your procedures if needed.
7. Recording your data
8. Graph your data (you can use one graph with different colors for each environment option)
9. Run a statistical analysis of your data
10. Answer any analysis questions
11. Write a paragraph conclusion summarizing results and findings as they relate to your hypothesis
Reminders:
· You can only change one variable at a time to have a valid experiment. The “choice chamber” has 3 compartments; so one compartment is the control, while the other 2 can be different variables.
· Try to control as many factors as possible, but keeps note of any issues that may affect your results and discuss them in your analysis and conclusion
· Make sure to collect data in a table as well as create a graph of your information, and explain the graph.
· You will need to review the statistical methods used to analyze the data. You don’t have to include all steps of the math in your report, but include important values and an explanation.
Material Options: (only include materials in your report that you actually use)
Choice chamber Petri dish
Filter paper Paper towels Water
Lamp (remember they generate heat as well as light)
Tin foil (cover to make dark)
Mulch
Dark paper
White paper
Grass
Dirt
Soap
Salt
* Any other material you want to bring in!
Analysis Questions (include discussion of these questions in your background and analysis sections):
1. Describe what innate and learned behaviors are. Give a possible example of each type in your pill bugs.
2. Explain the difference between taxis and kinesis and describe which was shone by your pill bugs and why.
3. How might there be a genetic basis for the pill bug behavior?
The Chi-Square Test
A statistical test that can test out ratios is the Chi-Square or Goodness of Fit test.
Chi-Square Formula
Observed value: the results from an experiment or test (sometime given to you)
Expected value: the expected outcome from a genetic cross or normal chance. What would happen given the null hypothesis (not change or no preference).
Degrees of freedom (df) = n-1 where n is the number of classes
Example: Let's test the following data to determine if it fits a 9:3:3:1 ratio.
Observed Values / Expected Values315 Round, Yellow See / (9/16)(556) = 312.75 Round, Yellow Se
108 Round, Green See / d (3/16)(556) = 104.25 Round, Green Se
101 Wrinkled, Yellow S / e (3/16)(556) = 104.25 Wrinkled, Yellow
32 Wrinkled, Green / (1/16)(556) = 34.75 Wrinkled, Green
556 Total Seeds / 556.00 Total Seeds
Number of classes (n) = 4
df = n-1 4-1 = 3
Chi-square value = 0.47
Enter the Chi-Square table at df = 3 and we see the probability of our chi-square value is greater than 0.90. By statistical convention, we use the 0.05 probability level as our critical value. If the calculated chi-square value is less than the 0 .05 value, we accept the hypothesis. If the value is greater than the value, we reject the hypothesis.
Therefore, because the calculated chi-square value of .47 is less than the p value of 7.82, we accept the hypothesis that the data fits a 9:3:3:1 ratio.
A Chi-Square Table
Accept:
2
· If X
value is less than
Reject:
2
· If X
value is greater
critical p value: mean accept null hypothesis or expected/predicted outcome, as it can happen by chance more that 5 percent of the time.
· If X2 values falls at .05
(5%) or higher, accept predicted/ null hypothesis
that critical p = statistically significant, meaning reject null hypothesis or reject expected, as it is unlikely to occur by chance given the parameters.
2
· If X value falls below
.05, then the event has less than a 5% chance of occurring by chance, so reject