BIOLOGYName:

Isopod LabGroup partners:

Value: 50 pointsDate:

In this lab, you will conduct experiments examining the responses of this organism to various environmental factors then hypothesize the reasons for these behaviors.

Objectives

After performing the lab, you should be able to :

Describe some aspects of animal behavior

Understand the adaptiveness of the behaviors studied

Introduction

Ethology is the study of animal behavior. Behavior is an animal’s response to sensory input. Orientation behaviors place the animal in its most favorable environment. In taxis, the animal moves toward or away from a stimulus. This 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, the movement is termed taxis. If an animal responds to bright light by random movement in all directions it is called kinesis.

Isopods are organisms that are members of the phylum Arthropoda, class Crustacea, which also includes shrimp and crabs. Some members of this group respire through gills. Others through a series of branching tubes called trachaea. Isopods are a diverse group of organisms existing on land, in fresh water, and in the ocean. In this lab, students work with terrestrial isopods, know as pill bugs, sow bugs, or roly-polies. These isopods live in damp, often dark, environments where they eat plant and animal matter.

PART A

Procedure – Kinesis in pill bugs

  1. Create a choice chamber consisting of two halves with a divider so that the pill bugs must travel through a small door to go from one side to the other. Place clean filter paper into both sides of the choice chamber.
  2. Using a disposable plastic pipet, add several drops of water to one side of the chamber. Don’t add too much water; you don’t want to moisten the other side of the chamber.
  3. Use a sorting brush to transfer 5 pill bugs to each side of the chamber then close the lid.
  4. Count and record in table 1 the number of animals on each side of the chamber every 30 seconds for 8 minutes. Continue to record the pill bugs’ movements, even if they all move to one side or stop moving.
  5. Return your pill bugs to the holding area.
  6. Add up and average each column in table 1
  7. The teacher will record each group’s average on the board and get an average for the class
  8. Record the class average data in table 2

TABLE 1 (5 points)

TimeNumber in Number in

(Min)Wet ChamberDry Chamber

0 ______

0.5______

1.0______

1.5______

2.0______

2.5______

3.0______

3.5______

4.0______

4.5______

5.0______

5.5______

6.0______

6.5______

7.0______

7.5______

8.0______

Total:______

Average: ______

TABLE 2: Class Average (4 points)

TimeNumber in Number in

(Min)Wet ChamberDry Chamber

8 minutes: ______

Part A analysis:

  1. Create a graph of your data from table A. Be sure to title the graph and label each axis with the appropriate labels and units. (5 points)
  2. In this controlled experiment, what was the independent variable? ______(1 point)
  3. What was the dependent variable? ______(1 point)
  4. What were the constants?______(1 point)
  5. In this experiment, each group did the same thing, so how many trials were there? ______(1 point)
  6. How did your data compare to the class average data? (1 point)
  1. What were some sources of error that may have affected the data? (1 point) ______
  1. What conclusion do you draw from your data for part A? What reasons do you think might explain the behavior observed? How could you improve this experiment? (5 points)

______

______

______

PART B – Testing the affect of Light on Isopod Kinesis

  1. Use aluminum foil to cover one side of the choice chamber. Fill in the following information before performing your experiment.
  2. What is the independent variable you chose?______(1 point)
  3. What is your prediction and hypothesis (if/then/because)? (1 point) ______
  1. What is the dependent variable in your experiment? (1 point) ______
  2. What are the constants in your experiment? (1 point) ______
  3. How many trials will you have? ______(1 point)

Procedure:

1.Start with a clean choice chamber

2.Use a sorting brush to transfer 5 pill bugs to each side of the chamber then close the lid. Cover one side of the chamber with aluminum foil.

3.Count and record in table 3 the number of animals on each side of the chamber every 30 seconds for 8 minutes. Continue to record the pill bugs’ movements, even if they all move to one side or stop moving.

4.Return your pill bugs to the holding area.

5.Add up and average each column in table 3

6.The teacher will record each group’s average on the board and get an average for the class

7.Record the class average data in table 4

TABLE 3 (5 points)

Time_Light Side__ __Dark Side_____

(Min)

0 ______

0.5______

1.0______

1.5______

2.0______

2.5______

3.0______

3.5______

4.0______

4.5______

5.0______

5.5______

6.0______

6.5______

7.0______

7.5______

8.0______

Total:______

Average: ______

TABLE 4: Class Average (4 points)

TimeNumber in Number in

(Min)Light Chamber Dark Chamber

8 minutes: ______

Post-lab analysis Part B

  1. Create a graph of your data from part B. Be sure to title the graph and label each axis with the appropriate labels and units. (5 points)
  1. How do your data compare to the class average? (1 point)
  1. What conclusion do you draw from your data for part B? Explain these results.

Does your conclusion support your hypothesis? (5 points)

______

______

______

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