Name Date
Assignment Title: Unit 3 Portfolio: Population and Ecosystems
What conditions will you simulate?
How does each condition help a population survive?
What is the population shown in the video? What ecosystem are they a part of?
Explain what limiting resources are. What effects would these have on populations?
What would happen to a population if there are no limiting factors present? Why?
What is the difference between interspecific competition and intraspecific competition?
The Fishery Simulation
During the fishery simulation limiting factors such as food, predators, pollution, and disease will be manipulated in order to test what makes the tuna population increase, decrease, or stay constant.
STEP 1
Generate a question for your investigation:
STEP 2
Hypothesis
What is the Independent Variable in this experiment?
___________________
Create a hypothesis for your investigation. Use the format below:
IF_______________________________________________,
THEN____________________________________________
________________________________________________.
What is the Dependent Variable in this experiment?
___________________
Simulation Directions:
Follow the tutorial in the simulation to familiarize yourself with how the simulation works. Read each screen carefully and be sure you understand each part of the tutorial before moving to Stage 1 of the simulation.
STEP 3
Experiment
Click here to access The Fishery Simulation
What are the control variables in this experiment?
Materials List:
Procedures (list steps)
1.
6.
2.
7.
3.
8.
4.
9.
5.
10.
Stage 1 Directions:
In this stage you will examine how birth rate, death rate, and migration rate affect the sustainability of the Avril Gulf tuna population.
Click on the “Show Normal Population Growth” box to see the graph of what happens to this population if reproduction, migration, and death rates are moderate
Collect Data
Explore what happens to the population as you change the three variables. Only change one variable at a time, other variables should be kept in the middle. Record observations of what happens to the sustainability of the population in the table below. Some have already been filled out for you
Variable
Observation of population at Low
Observation of population at Population at High
Reproduction
no change, remains at 20,000
Migration
Deaths
slower growth but reaches 100,000
Use the simulation to determine what settings for the three variables maintain the population at 60,000 fish. Record the graph you see and the settings used below. Make sure you include the dotted line and dashed line. The dashed line represents normal population growth while the dotted line represents population growth at the settings you set.
Predict what settings would maintain the population at 80,000 fish. Write down your predictions below, and then use the simulation to test your prediction. If necessary, change the settings as you run the simulation. Record the graph you see and the settings used below
Questions:
What are the 2 limiting factors present in this stage?
Stage Two Directions:
In this stage you will examine how predators, amount of food, and incidents of disease and pollution affect the sustainability of the Avril Gulf tuna population. Note that in Stage 2 you cannot control pollution or disease events, which will occur at random intervals
Collect Data
Explore what happens to the population as you change the two variables. Only change one variable at a time, other variables should be kept in the middle. Record observations of what happens below
What happens when the predators is lowered to none?
What happens when it is increased to many?
What happens when food is lowered to little?
What happens when it is increased to abundant?
Use the simulation to determine what settings for the three variables maintain the population at 60,000 fish. Record the graph you see and the settings used below. Make sure you include the dotted line and dashed line. The dashed line represents normal population growth while the dotted line represents population growth at the settings you set.
Predict what settings would maintain the population at 80,000 fish. Write down your predictions below, and then use the simulation to test your prediction. If necessary, change the settings as you run the simulation. Record the graph you see and the settings used below
Questions
What happened immediately when pollution occurred?How long did it take the population to recover after pollution occurred?
What happened immediately after disease occurred? How long did it take the population to recover after disease occurred?
Stage Three Directions:
In this stage you will examine how fishing intensity and length of fishing season affect the sustainability of the Avril Gulf tuna population.
Collect Data
Explore what happens to the population as you change the amount of fishing at different times of the year. Only change one variable at a time, other variables should be kept in the middle. Record observations of what happens below
What happens when there is heavy fishing at different times of year?
summer
fall
winter
spring
What happens when there is no fishing at different times of year?
summer
fall
winter
spring
B. Use the simulation to determine what settings for the three variables maintain the population at 60,000 fish. Record the graph you see and the settings used below. Make sure you include the dotted line and dashed line. The dashed line represents normal population growth while the dotted line represents population growth at the settings you set.
C. Predict what settings would maintain the population at 80,000 fish. Write down your predictions below, and then use the simulation to test your prediction. If necessary, change the settings as you run the simulation. Record the graph you see and the settings used below
Questions
Some fishing will occur, as humans interact with the environment. Find a pattern that will allow the tuna population to remain at a carrying capacity of 60,000. What fishing regulations would maintain this population size?
Stage Four Directions:
In this stage all of the variables can be manipulated to determine their collective
effect on the sustainability of the Avril Gulf tuna population.
Collect Data
Explore what happens to the population as you change the amount of fishing at different times of the year. Only change one variable at a time, other variables should be kept in the middle. Record observations of what happens below
What happens when:
food is abundant and there are no predators?
reproduction is low and death is high?
there is heavy fishing in spring and summer?
B. Use the simulation to determine what settings for the variables maintain the population at 60,000 fish. Record the graph you see and the settings used below. Make sure you include the dotted line and dashed line. The dashed line represents normal population growth while the dotted line represents population growth at the settings you set.
C. Use the simulation to determine what settings for the variables maintain the population at 60,000 fish. This time, incorporate the maximum amount of fishing possible. Record the graph you see and the settings used below. Make sure you include the dotted line and dashed line. The dashed line represents normal population growth while the dotted line represents population growth at the settings you set.
Questions
What factors allowed for the maximum amount of fishing while maintaining the fish population? Record the greatest amount of fishing allowable.
Which factors are density-dependent and which are density-independent?
How could a model, such as this simulation, help fisheries biologists make recommendations about setting fishing limits to ensure the survival of a population and cause minimal negative impacts to the ecosystem? Explain your answer. (3-5 sentences)
Summarize your lab report by answering the following questions.
5. Conclusion: written explanation of what you learned. This should be one paragraph explaining what you learned about populations and ecosystems (5-6 sentences, 250 words). Be sure to include ALL required vocab words from the list above and underline them.
Information to include:
Did your data support or refute your hypothesis?
What would you do to improve the experiment in the future?
What did you learn about this topic?
The conditions that will be simulated in this experiment include birth rate, death rate, migration rate, predators, food availability, pollution, disease, fishing intensity, and length of fishing season.
Each condition helps a population survive by either providing necessary resources for growth and reproduction (such as food availability) or by controlling factors that could harm the population (such as predators or disease).
The population shown in the video is the Avril Gulf tuna population, which is a part of the marine ecosystem. Limiting resources are essential resources that are in limited supply and can act as constraints on population growth. In this case, these resources include food, space, and other factors essential for the tuna population. A lack of these limiting resources would lead to overpopulation, competition, and ultimately a decline in the population.
If there are no limiting factors present, a population would experience exponential growth until it reaches the carrying capacity of the environment. This would lead to competition for resources, increased predation, and eventually a decline in the population due to resource depletion.
Interspecific competition is competition between different species for the same resources, while intraspecific competition is competition between individuals of the same species for the same resources.
The Fishery Simulation
- The independent variable in this experiment is the variable that is being deliberately changed by the experimenter.
- The dependent variable in this experiment is the variable that is being measured and recorded based on the changes made to the independent variable.
Control variables in this experiment include variables that are kept constant throughout the experiment to ensure that changes in the dependent variable are only due to changes in the independent variable.
In conclusion, this experiment demonstrated how various factors such as birth rate, death rate, migration, predators, food availability, pollution, disease, and fishing intensity can impact the sustainability of a population. By manipulating these factors, we can better understand how populations interact with their environment and how to manage resources effectively to ensure the survival of populations and maintain balance in ecosystems. Further improvements to this experiment could involve more in-depth analysis of interactions between multiple factors and their cumulative effects on populations. The importance of balancing human activities like fishing with sustainable practices was also highlighted in this experiment.
Vocabulary
REQUIRED
OPTIONAL (Should use at least 6 for full credit)
population
interdependence
consumer
acid
ecosystem
predator
competition
base
abiotic factors
prey
limiting factor
photosynthesis
biotic factors
producer
resource
carbon dioxide
In this experiment, we explored the interactions within a population of tuna in the Avril Gulf ecosystem. We learned about the interdependence of the tuna population with its environment, including factors such as food availability, predators, and competition for resources. The population of tuna serves as both consumers and producers in the ecosystem, interacting with other species as both predators and prey.
Limiting factors such as food availability, predators, and pollution can directly impact the sustainability of the tuna population. These biotic and abiotic factors play a crucial role in maintaining a balance within the ecosystem. For example, the availability of resources such as carbon dioxide for photosynthesis is essential for the survival of producers and, in turn, impacts the entire food chain within the ecosystem.
Through the fishery simulation, we were able to observe how manipulating variables such as birth rate, death rate, migration, predators, food availability, pollution, disease, and fishing intensity can affect the population dynamics of the tuna. It became clear that human activities, like fishing, can have a significant impact on populations and ecosystems. The experiment highlighted the importance of understanding these interactions to make informed decisions about resource management and conservation efforts.