Module 9S2 Changes in Populations
Lesson 4.9.1S2
4.9.1S2 page 2
Explore
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The size of a population is the result of four population determining factors at work. These factors can increase, decrease, or work together to maintain population size. They are natality, mortality, immigration, and emigration.
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Read
Read pages 707–708 in the textbook. Attempt to derive a formula that expresses the effect of natality, mortality, immigration, and emigration on change in population numbers. Then read pages 708-712.
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Self-Check
To see if your formula works, try the following questions and check your work.
- A case study of Swans in Grande Prairie
A breeding flock of trumpeter swans near Grande Prairie is made up of 50 pairs. This year there were 165 live hatchlings, no new birds joined the flock, 5 animals were shot, and 8 did not return this spring from their migration.
How has the population of trumpeter swans changed?
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Try This
- Complete the "4.11 Population Size" drag-and-drop activity.
Self-Check
SC 1.
Human Population Change
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Answer the following questions. You may wish to score your response. (4 marks)
- The Canadian population is growing significantly yet birth rates are dropping. Use the dN formula to suggest three different explanations.
- Population numbers have much to do with the lifespan of the organism. Why would women of Japanese ethnicity have a longer life expectancy when they live in Japan than when they live in North America? Suggest three possible reasons and explain your answers.
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Discuss
Native aboriginal Albertans are in many cases given different legal hunting bag limits than non-natives. Research the reasons for this difference and post a response to the question of whether the difference in bag limits is justified. Discuss your work with your instructor and other students.
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Self-Check
SC 2.
How might a drought that decreased grass populations affect herbivore population numbers? Referring to the formula for ∆N, suggest four different ways.
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