Brine Shrimp Lab
Pre-Lab Questions:
1. List some abiotic factors in an ecosystem.
-Some abiotic factors include water, soil, sunlight, air, and rocks
2. List some biotic factors in an ecosystem.
-Some biotic factors include plants, animals, bacteria, and fungi.
Hypothesis: The brine shrimp will move to quadrant four of the Petri dish as they will prefer light over darkness. The independent variable is the light level. The dependent variable is the location of the brine shrimp. The controlled variables include the salt concentration of the water, the time allotted, and the temperature of the water. The control group has no construction paper over any part of the Petri dish while the experimental groups have construction paper covering one-half of the Petri dish.
Problem: Do brine shrimp prefer to live in a light-filled habitat or a dark one?
Materials:
-Two Petri dishes
-Marker
-100 mL of brine shrimp solution (50 mL for each dish)
-Pipette
-Thermometer
-Lamp
Procedure:
1. Obtain two Petri dishes and divide each into four equal areas with a marker and label them with numbers 1-4.
2. Add 50 mL of the brine shrimp solution to each Petri dish using the pipette.
3. Count the number shrimp in each of the four areas in each Petri dish.
4. Cover one-half of one of the Petri dishes with black construction paper so that all of area 1 is covered and one-half of areas 2 and 3 are covered. Do not cover any of the other Petri dish.
5. Record the temperature of each of the 4 sections in each Petri dish.
6. Allow the Petri dishes to sit under a lamp for 30 minutes.
7. After 30 minutes, record the number of shrimp in each of the four areas in each Petri dish.
8. Record the temperature of each of the 4 sections in each Petri dish.
Observations and Data:
1. List some abiotic factors in an ecosystem.
-Some abiotic factors include water, soil, sunlight, air, and rocks
2. List some biotic factors in an ecosystem.
-Some biotic factors include plants, animals, bacteria, and fungi.
Hypothesis: The brine shrimp will move to quadrant four of the Petri dish as they will prefer light over darkness. The independent variable is the light level. The dependent variable is the location of the brine shrimp. The controlled variables include the salt concentration of the water, the time allotted, and the temperature of the water. The control group has no construction paper over any part of the Petri dish while the experimental groups have construction paper covering one-half of the Petri dish.
Problem: Do brine shrimp prefer to live in a light-filled habitat or a dark one?
Materials:
-Two Petri dishes
-Marker
-100 mL of brine shrimp solution (50 mL for each dish)
-Pipette
-Thermometer
-Lamp
Procedure:
1. Obtain two Petri dishes and divide each into four equal areas with a marker and label them with numbers 1-4.
2. Add 50 mL of the brine shrimp solution to each Petri dish using the pipette.
3. Count the number shrimp in each of the four areas in each Petri dish.
4. Cover one-half of one of the Petri dishes with black construction paper so that all of area 1 is covered and one-half of areas 2 and 3 are covered. Do not cover any of the other Petri dish.
5. Record the temperature of each of the 4 sections in each Petri dish.
6. Allow the Petri dishes to sit under a lamp for 30 minutes.
7. After 30 minutes, record the number of shrimp in each of the four areas in each Petri dish.
8. Record the temperature of each of the 4 sections in each Petri dish.
Observations and Data:
Picture: Temperature being taken at experimental group five before the lamp is turned on.
Analysis and Conclusions:
Lab Questions:
1. What temperature do brine shrimp appear to prefer? Support your answer.
According to the data, the brine shrimp do not seem to prefer a specific temperature. In some cases, two quadrants had the same temperature but more brine shrimp were in one of them. However, the data could be inaccurate if temperatures were not taken correctly or the shrimp were not counted properly.
2. What light level do brine shrimp appear to prefer? Support your answer.
The data is inconclusive because in some experimental groups, the shrimp preferred the darkness (experimental group one), while in others, the shrimp preferred the light (experimental group three). The data is probably inaccurate due to miscounting of the shrimp after the thirty minutes.
3. Do the brine shrimp appear to be attracted to the light, temperature, or both? Support your answer.
It is impossible to tell whether the shrimp were attracted to the light or the temperature as different results were gathered from different experimental groups. For example, Quadrant One of experimental groups two and three both had the same temperature and were covered by the construction paper. However, two shrimp were found in this quadrant in experimental group two, while none were found in experimental group three. Also, in many of the groups, the shrimp were evenly spread out throughout areas both with and without light.
4. Did you have outliers that moved to an area of the plate that others did not prefer? Explain this result.
In most of the experimental groups, the shrimp tended to be somewhat evenly dispersed throughout the plates. However, in experimental group five, eleven shrimp congregated in Quadrant One while only three outliers were in Quadrant Two. This is possibly because the temperature was higher by one degree in Quadrant Two and the difference was only noticeable by a few shrimp. The three might have also been on their way to Quadrant One when time was called.
5. How can this be applied to other organisms in aquatic ecosystems? Answer the question in a well-developed paragraph.
If this experiment were to be repeated and had more conclusive results, the shrimps' preferences towards light and temperature might be applicable to other similar organisms in aquatic ecosystems. However, it must be noted that hundreds of factors can affect an organism's chosen location. In this experiment, just two of the factors were really considered: light and temperature. In a larger aquatic ecosystem, salinity, pH, and many other factors would have to be tested for or controlled, along with light and temperature.
General Conclusions/Analysis:
The data provided by the experiment was inconclusive in proving or disproving the hypothesis. It is impossible to tell whether the shrimp preferred lightness as each experimental group yielded different results. If the lab were to be repeated, there would be many necessary changes such as having the same amount of shrimp in each petri dish and finding a way to control the temperature to be equal in each dish and each quadrant. This experiment demonstrated the possible various factors that can determine the presence of an organism. It also demonstrated the necessity of controlling all variables except one so the results are a clear indication of which factor changed the outcome.
Lab Questions:
1. What temperature do brine shrimp appear to prefer? Support your answer.
According to the data, the brine shrimp do not seem to prefer a specific temperature. In some cases, two quadrants had the same temperature but more brine shrimp were in one of them. However, the data could be inaccurate if temperatures were not taken correctly or the shrimp were not counted properly.
2. What light level do brine shrimp appear to prefer? Support your answer.
The data is inconclusive because in some experimental groups, the shrimp preferred the darkness (experimental group one), while in others, the shrimp preferred the light (experimental group three). The data is probably inaccurate due to miscounting of the shrimp after the thirty minutes.
3. Do the brine shrimp appear to be attracted to the light, temperature, or both? Support your answer.
It is impossible to tell whether the shrimp were attracted to the light or the temperature as different results were gathered from different experimental groups. For example, Quadrant One of experimental groups two and three both had the same temperature and were covered by the construction paper. However, two shrimp were found in this quadrant in experimental group two, while none were found in experimental group three. Also, in many of the groups, the shrimp were evenly spread out throughout areas both with and without light.
4. Did you have outliers that moved to an area of the plate that others did not prefer? Explain this result.
In most of the experimental groups, the shrimp tended to be somewhat evenly dispersed throughout the plates. However, in experimental group five, eleven shrimp congregated in Quadrant One while only three outliers were in Quadrant Two. This is possibly because the temperature was higher by one degree in Quadrant Two and the difference was only noticeable by a few shrimp. The three might have also been on their way to Quadrant One when time was called.
5. How can this be applied to other organisms in aquatic ecosystems? Answer the question in a well-developed paragraph.
If this experiment were to be repeated and had more conclusive results, the shrimps' preferences towards light and temperature might be applicable to other similar organisms in aquatic ecosystems. However, it must be noted that hundreds of factors can affect an organism's chosen location. In this experiment, just two of the factors were really considered: light and temperature. In a larger aquatic ecosystem, salinity, pH, and many other factors would have to be tested for or controlled, along with light and temperature.
General Conclusions/Analysis:
The data provided by the experiment was inconclusive in proving or disproving the hypothesis. It is impossible to tell whether the shrimp preferred lightness as each experimental group yielded different results. If the lab were to be repeated, there would be many necessary changes such as having the same amount of shrimp in each petri dish and finding a way to control the temperature to be equal in each dish and each quadrant. This experiment demonstrated the possible various factors that can determine the presence of an organism. It also demonstrated the necessity of controlling all variables except one so the results are a clear indication of which factor changed the outcome.