Copy of 206 Population Growth Lab Report

2.06- Population Growth Lab Report Instructions: In this lab activity, you will investigate how predation, starvation, birthrates, and death rates influence the killer whale and seal populations within a marine ecosystem. Submit your lab report to your instructor when completed. Title Your Name: Andrew Mendelson Teacher Name: Ms. Alden Hypothesis: Before you begin, form a hypothesis that predicts the outcome of this study. If the starting population of the seals is higher than the whales, the carrying capacity of the seals will be lower(higher or lower) than the carrying capacity of the whales. Procedures: 1. Complete the table by performing the following calculations. The first row has been completed for you as a model to follow. a) Determine to total of seal deaths for each year of the study. b) Calculate the seal population change by comparing the births and deaths for the year. The seal population change can be positive or negative. c) Calculate the seal population for the year by adding or subtracting the population change to that of the previous year. 2. Fill in data table 2 with the same seal population from data table 1. 3. Create two line graphs on the plot provided. In one color for the seal population and another for the whale population. a) Use the drawing tool in word processor to draw the lines. b) Both lines should be graphed from left to right.

c) Make sure to use the axes value for seals on the left and whales on the right. d) Draw a horizontal dotted line across the graph that represents the carrying capacity for the whales and seals. (Hint: Where do the populations stabilize and growth slows to zero?) e) Label the carrying capacity line by inserting a text box or using the draw tool. 4. Complete the conclusion and reflection questions. Data Analysis: Data Table 1 Year Seal Births Predation Starvation Seal Deaths Population Change Seal Population 1 N/A N/A N/A N/A N/A 100 2 50 30 5 35 15 115 3 100 45 15 60 40 155 4 90 60 17 77 13 168 5 95 85 25 110 -15 153 6 85 73 21 94 -9 144 7 65 60 17 77 -12 132 8 60 50 14 64 -4 128 9 64 55 10 65 -1 127 10 65 55 10 65 0 127

110 6 100 4 90 2 Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Conclusion: Answer the following questions as your conclusion in complete sentences. ● According to the graph, what happened to the seal population as the whale population increased? The whale population increased as the seal population actually decreased ● What appears to be the carrying capacity of the whale and seal population in the graph? (Hint: Where do the populations stabilize and growth slows to zero?) The carrying capacity for the whales topped at 19 while the seals carrying capacity topped at 168 ● Between which years of the study does overshoot occur for each population? For the whales the overshoot occurred between years 5 and 6 while for the seals it occurred in between years 3 and 5 ● Does your data support or fail to support your hypotheses (include examples)? My data is consistent with my hypothesis. I said that the carrying capacity of seals would be less than that of the whales. While the number of the whales increased the number of the seals decreased. ● What are the limitations of the population growth study? Is it a realistic representation of an arctic marine ecosystem? Note: Please provide detailed support for your opinion. No this is not an accurate or realistic depiction of an arctic marine ecosystem. The whales do not only go for the seals, however they do have other prey that they live off of. While the representation of the arctic marine ecosystem is not realistic, it is true that the higher the number of whales, the lower number of seals there will be.

Post-Lab Reflection Questions Answer the reflection questions using what you have learned from the lesson and your experimental data. It will be helpful to refer to your class notes. Answer questions in complete sentences. 1. If another source of prey were available to the whales, what changes in population size would you expect for the seals and the whales? Since the whales would be living off of another species, the number of seals in the population would most likely sky rocket, and the ecosystem would not be able to sustain it any longer. 2. Calculate the rate of population change for the whales and the seals for the full length of the study. ( Hint: Divide the total change in population size (negative or positive) by the total change in time, which is 10 years.) Seals: 11.5,15.5,16.8,15.2,14.4,13.2,12.8,12.7,12.7 Whales: 0.7,1.1,1.5,1.9,1.7,1.2,1,0.9,0.9 3. In this lesson, you learned about two patterns of population growth and decline, the sigmoid and peak phenomena. Does the seal and killer whale relationship represent a sigmoid or peak phenomenon? Justify your answer with supporting details. ● The relationship between the two is a peak phenomenon because the whales are depending on the seals for food. Whales would suffer if the number of seals in the population would decrease, however if the seal population would rise, sowould the whale population. 4. Climate change (an abiotic factor) has slowly decreased habitat for the arctic seals. a) Predict how a reduction in habitat could change the behavior of the killer whales. Reducing the habitat would end up decreasing the seal population, which would in turn decrease the whale population. b) Explain how this scenario would affect the carrying capacities for both the whales and the seals. Because of the limited space, it would reduce the carrying potential because there is no space for the seals to be able to safely give birth to their offspring. This in turn could reduce the carrying capacity for the whales.