Lab 11 Lab Report b1710

Wenzheng Yu AP Biology Period 1 Lab Eleven: Animal Behavior Introduction The overall purpose of this lab was to examine different types of animal behavior. In the first half of the lab, the behavior of pillbugs was studied, in particular with regard to kinesis, which is a random movement as a result of a stimulus. First, the pillbugs’ responses to moisture were examined. It was hypothesized that if the pillbugs could choose to settle in a chamber that was moist or a chamber that was dry, then more pillbugs would prefer the moist chamber. Then, in the independently designed experiment, the pillbugs’ responses to background color of their environment were tested. It was hypothesized that if the pillbugs could choose to settle in a chamber that had a black background or a chamber that had a white background, then more pillbugs would prefer the dark chamber. In the second half of the lab, the aggressive behavior of the Siamese fighting fish (also known as Betta fish) was examined. In particular, the effect of laser pointer light on the behavior of the Betta fish was investigated by counting the rate of movement of the fish’s pectoral fins. It was hypothesized that if a laser pointer was shined on the fish, he would move his pectoral fins at a faster rate compared to his usual rate of movement of pectoral fins. The types of behaviors investigated in this lab include taxis and kinesis. Whereas the animal moves either toward or away from a certain stimulus in taxis, the animal moves randomly in response to a stimulus in kinesis. Another type of behavior that this lab involves is agonistic behavior, which refers an animal showing aggressive or submissive behavior in response to a given stimulus. Materials 

10 pillbugs 1

            

Mirror Ruler 2 petri dishes ed together Petri dish cover Paper towel Water Black construction paper White paper Timer 1 male Betta fish 1 laser pointer 1 Thermometer A pair of Scissors

Procedure Part 11A: 1. 10 pillbugs were obtained and placed on the wet paper towel in a petri dish. A petri dish cover was placed on the dish to prevent the pillbugs from climbing out. 2. For 10 minutes, extensive notes were taken of the pillbugs’ general appearance, movements about the dish, and interactions with each other. Any behaviors that involved 2 or more pillbugs were noted. A sketch of a pillbug was produced. 3. A choice chamber consisting of two petri dishes ed together was obtained. 4. A piece of paper towel was wetted and placed in one chamber; while a dry piece of paper towel was placed in the other chamber. 5. 5 pillbugs were placed in each chamber. 6. Every 30 seconds for 10 minutes, the number of pillbugs on each side of the choice chamber was counted and recorded. 7. The number of pillbugs in the wet chamber and the number in the dry chamber were graphed.

2

8. In the independently designed part, a circle the size of a petri dish was cut out from white paper. A circle of the same size was cut out from black construction paper. 9. Both pieces of paper were wetted and placed in each of the chambers. 10. 5 pillbugs were placed in each chamber. 11. Every 30 seconds for 10 minutes, the number of pillbugs on each side of the choice chamber was counted and recorded. 12. The number of pillbugs in the black background chamber and the number in the white background chamber were graphed. 13. The pillbugs were disposed of and the petri dishes were washed and put back. Independent variable – The independent variable for the general part was the moisture of the petri dish as altered by whether the paper towel was wet or dry. The independent variable for the independently designed part was the background color of the petri dish, whether it was black or white. Dependent variable – The dependent variable for the general part was the number of pillbugs located in the wet chamber versus the number of pillbugs located in the dry chamber. The dependent variable for the independently designed part was the number of pillbugs located in the black background chamber versus the number of pillbugs located in the white background chamber. Controlled variables – The controlled variables for the general part included light, temperature, pH, size of each petri dish, etc. The controlled variables for the independently designed part included temperature, moisture, light, size of each petri dish, etc. Organism/Apparatus – the 10 pillbugs (also known as sowbugs) 3

Part 11B: 1. A male Siamese fighting fish was obtained in a plastic container. 2. The male Betta was observed, including whether there were a collection of bubbles floating at the surface of the tank. Also, the purpose of the upward pointed mouth was noted and speculated. 3. The behavior of the Betta fish when he was alone in the tank was recorded in detail. Physical factors such as water temperature were also noted. 4. A mirror was lowered into the plastic container and left there for 10 minutes. The fish’s behavior when he noticed the mirror was described, including his aggressive and submissive behaviors. 5. As a group, several variables that would either increase or decrease the frequency of aggressive behavior in Betta fish were brainstormed. One of these ideas, light, was developed into a proposal to test how it affected the aggressive behavior of the Betta fish. 6. Before testing this variable, three control trials were conducted by counting the number of times the fish moved his pectoral fins in a 30-second period under regular conditions without additional light. 7. Three experimental trials were performed in which a laser pointer was pointed from the top to the fish. The rate of his pectoral fins movement was recorded for each 30-second period. 8. All the data were converted to rate of movement per minute. 9. The average for the control trials and the average for the experimental trials were computed and compared to examine whether and how the stimulus of light affected the behavior of Siamese fighting fish. 4

Independent variable – The independent variable was the presence of additional light in the form of the laser pointer to the environment of the Betta fish. Dependent variable – the dependent variable is the rate of movement of the Betta fish’s pectoral fins. Controlled variables – Temperature, humidity, noise Organisms/Apparatus – one male Betta Fish Results Part 11A: Pillbug Movement over Time Between wet and dry chambers Time (min) 0

Number in wet chamber 5

Number in dry chamber 5

0.5 1.0

7 7

3 3

1.5 2.0 2.5 3.0

7 7 7 7

3 3 3 3

3.5 4.0

7 8

3 2

4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0

8 8 8 8 8 8 8 9

2 2 2 2 2 2 2 1

Notes Equal number of pillbugs in each chamber to begin with In dry chamber, pillbugs hide under paper towel

One pillbug climbed onto the top of the paper towel One pillbug chose to move to wet chamber

One pillbug moved to wet 5

chamber 8.5 9.0 9.5 10.0

9 9 9 9

1 1 1 1

number of pillbug in chamber

Pillbug Movement over Time Between wet and dry chamber 10 8 6 Wet chamber

4

Dry chamber

2 0 0

2

4

6

8

10

time (min.)

Description: From the above table and graph, it is evident that as time went on, more pillbugs chose to settle in the wet chamber. By the end of the 10-minute period, only one pillbug was left in the dry chamber; the rest all proceeded to reside in the wet chamber. Pillbug Movement over Time Between black and white chambers Time (min) 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Number in black background chamber 5 4 4 4 4 4 4 4 2 2 2

Number in white background chamber 5 6 6 6 6 6 6 6 8 8 8 6

number of pillbug in chamber

5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0

2 2 2 2 1 1 1 1 1 1

8 8 8 8 9 9 9 9 9 9

Pillbug Movement over Time Between black and white chamber 10 8 6 4

black chamber

2

white chamber

0 0

5

10

15

time (min.)

Description: According to the data table and graph, as time went on, the number of pillbugs in the white background chamber increased while the number of pillbugs in the black background chamber decreased. By the end of the 10-minute period, nine pillbugs were found to be in the white background chamber whereas only one pillbug was seen in the black background chamber. Part 11B: Effect of light on pectoral fins movement rate

Trial 1

Pectoral fins movement rate Trial 2 Trial 3

Average 7

Control Laser pointer light Description: According to the above table, the rate of the Betta fish’s pectoral fins movement was roughly 50 times higher per minute under the laser pointer than under ordinary light conditions. Conclusion Having done this lab, several conclusions can be drawn. For the pillbug part, pillbugs indeed prefer moist and damp conditions, as shown by the fact that an overwhelming majority of pillbugs chose to move to the wet chamber as opposed to the dry chamber. This is not surprising because pillbugs use gill-like structures to exchange gases. Therefore, they require a moist environment to breathe. The pillbugs’ response to moisture can best be classified as taxis since the isopod moved toward the stimulus, the wet chamber, instead of moving about randomly. In the independently designed experiment, the data collected were inaccurate since background research show that pillbugs generally prefer dark environment as opposed to light environment. This is due to the fact that it is usually more humid and damp in dark environments. Several reasons could for the experimental error. One of them could be that the number of pillbugs involved in the experiment was only ten. The sample size might not have been large enough to provide accurate results. Also, the moisture content on the black and white papers could have differed. In other words, some of the controlled variables, such as moisture, may not have been fully eliminated during the experiment. For the Betta fish part of the lab, it could be concluded that the presence of light from the laser pointer increased the aggressive behavior of the Betta fish. The rate of the

8

pectoral fins movement was drastically higher when the fish was shined upon by the laser pointer. This was in agreement with what was hypothesized. When the Betta fish realized that a strange light source was coming to him, he probably thought that some predator or harm was on its way. Therefore, it responded with aggressive behavior, as demonstrated with his more rapid movement of his pectoral fins. This allows the Betta fish to scare off the predator(s) emitting the light and therefore contributes to the long-term evolutionary survival of the fish.

9