Rabbit Population by Season

Student Exploration: Rabbit Population by Season Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. Vocabulary: carrying capacity, density-dependent limiting factor, density-independent limiting factor, limiting factor, population, population density Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. Suppose you had a pet rabbit. What would the rabbit need to stay alive and healthy? Clean environment, food, water, access to natural habitat 2. A female rabbit can give birth to over 40 baby rabbits a year. Suppose all of her offspring survived and reproduced, all of their offspring survived and reproduced, and so on. If that happened, in only eight years the mass of rabbits would exceed the mass of Earth! So, why aren’t we overrun with rabbits? What keeps the rabbit population in check? Predators that prey on rabbits keep them in check as they are constantly hunting and eating the rabbit population. Gizmo Warm-up A population is a group of individuals of the same species that live in the same area. The size of a population is determined by many factors. In the Rabbit Population by Season Gizmo, you will see how different factors influence how a rabbit population grows and changes. 1. Select the BAR CHART tab. What is the size of the initial rabbit population? 0 2. Select the TABLE tab. Click Play ( one year. ), and allow the simulation to run for A. In which season did the rabbit population increase the most? Spring B. In which season did the rabbit population increase the least? 1. Think about it: A limiting factor is any factor that controls the growth of a population. What do you think are some of the limiting factors for the rabbit population? Snow and ice during winter, less food as well. 2. Run Gizmo: Select the DESCRIPTION tab. Set the Simulation speed to Fast. Select the GRAPH tab. Click Play, and allow the simulation to run for at least 10 years. (Note: You can use the zoom controls on the right to see the whole graph.) A. Describe how the rabbit population changed over the course of 10 years. It had a slow start then kept going down then up every year as the seasons changed. Each year of seasons went down then up then back down showing the rabbit population in correlation to the seasons. B. What pattern did you see repeated every year? I saw that every year during winter the population slowed down then boomed during spring, then it went back down during fall. C. How could you explain this pattern? The different seasons change their habitat. During winter the ground is cold and barren and there is little food to eat, during spring the weather is warmer and rabbits have the most chance at reproducing. During fall it becomes colder and starts leading into winter. 3. Analyze: The carrying capacity is the maximum number of individuals of a particular species that an environment can support. All environments have carrying capacities. A. What is this environment’s approximate carrying capacity for rabbits? (Note: Average the summer and winter carrying capacities.) About 400 Introduction: Population density is the number of individuals in a population per unit of area. Some limiting factors only affect a population when its density reaches a certain level. These limiting factors are known as density-dependent limiting factors. Question: How does a density-dependent limiting factor affect carrying capacity? 1. Think about it: What do you think some density-dependent limiting factors might be? There might not be enough food for the amount of rabbits, or overpopulation which causes scarcity in other resources. 2. Predict: Suppose a shopping mall is built near a rabbit warren, leaving less land available for rabbits. How will this affect the environment’s carrying capacity? This will affect the environment's carrying capacity by limiting the amount of space the rabbit population has to live and use resources in. 3. Experiment: Use the Gizmo to find the carrying capacity with Ample, Moderate, and Little land. List the carrying capacities below. Ample: 410 330 Moderate: 100 Little: 4. Analyze: How did the amount of space available to the rabbits affect how many individuals the environment could support? It decreased the carrying capacity of the population drastically as land was taken away. 5. Infer: Why do you think limiting a population’s space decreases the carrying capacity? Because the smaller the environment the less it can support at once. 6. Challenge yourself: Other than space, what might be another density-dependent limiting factor? Explain. The amount of vegetation in one area, this can affect food sources and temperature in the habitat. Introduction: Not all limiting factors are related to a population’s density. Density-independent limiting factors affect a population regardless of its size and density. Question: How do density-independent limiting factors affect how a population grows? 1. Think about it: What do you think some density-independent limiting factors might be? the seasons because of how they affect the environment itself. 2. Gather data: Click Play. Allow the population to reach carrying capacity. Click Pause ( ). Select the GRAPH tab and click the camera ( ) to take a snapshot of the graph. Right click the image and paste the snapshot into the box below. Label the graph “Normal Weather.” Normal Weather 3. Predict: How do you think a period of harsh winters will affect the rabbit population? It will reduce the population and carrying size of the environment. 7. Predict: How do you think a period of hot summers will affect the rabbit population? It will let them grow ore and increase carrying size. 8. Investigate: Deselect Cold spring. Select Hot summer. Click Play, and observe how the population changes over a period of five years. Paste a snapshot of the graph in the box below. Label the graph “Hot Summer.” Hot summer A. How does the Hot Summer graph differ from the Normal Weather graph? Instead of a slow transition between seasons there is a spike around summer and then a sudden drop back to fall and winter. B. What do you think most likely caused the differences seen in the two graphs? Rapid population growth in the summer and quick decline because of winter and fall. 9. Think and discuss: Other than unusual weather, what might be another density-independent limiting factor that could affect the rabbit population? If possible, discuss your answer with your classmates and teacher. Weather during each season ie. Extra rain, Heatwave, drought, storms.