Brine Shrimp Lab
Background information:
The individuals within a population of a specific species of organism respond to certain features of their environment and ignore others. Many characteristics of a habitat are variable from time to time or at different locations within the habitat. Temperature, quantity of light, and pH often vary in aquatic habitats. When a specific environmental factor varies continuously over a distance, a gradient exists. Light intensities can range from absolute darkness to extreme brightness. A shady spot may be a few degrees cooler than a position in direct sunlight only a few meters away. The pH of a lake or stream may also vary from place to place. It seems logical to expect that certain conditions would be most suitable for an organism to thrive and that individuals differ from another in their abilities to detect environmental changes and in their abilities to respond to changes.
If we are to determine the significance of an environmental factor to a specific kind of organism, first we need to isolate the factor we are examining from other variables. Then, we can present an organism with a gradient along which it can move to select the most variable conditions. If the organisms move to specific positions along the gradient, we can see that the particular variable was detected by the organism and that it selected a particular intensity of that variable.
Prelab:
1. List some abiotic factors in an ecosystem: wind, rain, water movement
2. List some biotic factors in an ecosystem: Animals, Plants, algae, bacteria and decomposers
Hypothesis:The shrimp will swim away from the cold quadrant, and the heat, and will swim towards and be attracted to the light.
Independent Variable: Salinity, Temperature
Dependent Variable: number of eggs to hatch
Controlled variables: The number of eggs
Control group: The Petri dish with just distilled water and no salt.
Experimental Group: Brine shrimp in the petri dish
Procedure:
Points of note:
a. Allow the brine shrimp sufficient time to move to their preferred position along the gradient and distribute equally.
b. Collect data concerning population density at four positions along the gradient.
c. Make sure to rinse and dry the thermometer between measurements.
Control group
1. Obtain a Petri dish and divide it into four equal areas with a marker and label them with numbers 1-4.
2. Add 50 mL of the brine shrimp solution to the Petri dish.
3. Count the number shrimp in each of the four areas.
4. Record the temperature for each of the 4 sections.
5. Allow the Petri dish to sit under a lamp for 30 minutes.
6. After 30 minutes, record the number of shrimp in each of the four areas.
7. Record the temperature of each of the 4 sections.
Light group
1. Obtain a Petri dish and divide it into four equal areas with a marker and label them with numbers 1-4.
2. Add 50 mL of the brine shrimp solution to the Petri dish.
3. Count the number shrimp in each of the four areas.
4. Cover ½ of the Petri dish with black construction paper so that all of area 1 is covered and ½ of areas 2 and 3 are covered.
5. Record the temperature of each of the 4 sections.
6. Allow the Petri dish to sit under a lamp for 30 minutes.
7. After 30 minutes, record the number of shrimp in each of the four areas.
8. Record the temperature of each of the 4 sections.
Observations:
Data Tables:
Conclusions :
1. What temperature does brine shrimp appear to prefer? Support your answer. They seem to prefer warm temperatures, not hot temperatures. The tables show that the quadrant with less temperature seem to have more shrimp.
2. What light level does brine shrimp appear to prefer? Support your answer. They seem to prefer high light level. When i was observing the brine shrimp, they did not like being in the area with less light.
3. Do the brine shrimp appear to be attracted to the light, temperature, or both? Support your answer. They seem to be attracted to both because in my observations they moved to where there was light and warm temperature.
4. Did you have outliers that moved to an area of the plate that others did not prefer? Explain this result. Yes, but it was few. Most seem to prefer higher light level and just right temperatures.
5. How can this be applied to other organisms in aquatic ecosystems? Answer the question in a well-developed paragraph. This can be applied to other organisms in the aquatic ecosystems because of there preferences. Some fish live on the top of the ocean because they prefer the sunlight to live. Other fishes live in the very bottom of the ocean because that is what they prefer to live with. Also, their body's and organs depend on the things like the temperature, or sunlight.
General Analysis and Conclusions:
My hypothesis was correct. The results supported the hypothesis. Better separation of the quadrants could better accurate the results of this lab. An application to major ideas in the course would be if a change in the environment occurs, even the microscopic organisms will be affected and then affect the rest of the ecosystem.
1. What temperature does brine shrimp appear to prefer? Support your answer. They seem to prefer warm temperatures, not hot temperatures. The tables show that the quadrant with less temperature seem to have more shrimp.
2. What light level does brine shrimp appear to prefer? Support your answer. They seem to prefer high light level. When i was observing the brine shrimp, they did not like being in the area with less light.
3. Do the brine shrimp appear to be attracted to the light, temperature, or both? Support your answer. They seem to be attracted to both because in my observations they moved to where there was light and warm temperature.
4. Did you have outliers that moved to an area of the plate that others did not prefer? Explain this result. Yes, but it was few. Most seem to prefer higher light level and just right temperatures.
5. How can this be applied to other organisms in aquatic ecosystems? Answer the question in a well-developed paragraph. This can be applied to other organisms in the aquatic ecosystems because of there preferences. Some fish live on the top of the ocean because they prefer the sunlight to live. Other fishes live in the very bottom of the ocean because that is what they prefer to live with. Also, their body's and organs depend on the things like the temperature, or sunlight.
General Analysis and Conclusions:
My hypothesis was correct. The results supported the hypothesis. Better separation of the quadrants could better accurate the results of this lab. An application to major ideas in the course would be if a change in the environment occurs, even the microscopic organisms will be affected and then affect the rest of the ecosystem.