Name ______Period #______Date ______
Chapter 4 Population Biology (2nd try) TAKE HOME EXAM
MUST TURN IN MONDAY November 30, 2009!!!!
No late tests will be accepted!!!!
Completion
Complete each sentence or statement.
1. Demographers collect and study data about the age structure, geographic distribution, and ______of human populations.
2. Instead of growing explosively, population growth tends to level off because the population reaches the ______of a particular environment.
3. The production of many offspring in a short period of time is characteristic of a ______life-history pattern.
4. Food, water, or shelter could be ______factors on the growth of a population.
5. A population of bacteria that doubles its size every 20 minutes exhibits ______growth.
6. A(n) ______-shaped curve describes the tendency of a population to grow without limit to its size.
Short Answer (3 points)
Answer the following using COMPLETE SENTENCES!!!!!
7. Discuss the effects you would expect on two fictional countries, Deserland and Agriland, if large numbers of people immigrate to Agriland from Deserland.
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8. The United States is largely populated by descendants of immigrants from other nations. During the past 165 years, 52.5 million people have immigrated to this country, resulting in a 25 percent growth in total population. Hypothesize about the effects such immigration has had on the population growth rate.
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9. Discuss the demographic trends that have major effects on population growth rates in humans.
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10. Describe the general characteristics and give two examples of organisms that employ a strategy of rapid reproduction that produces many offspring.
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In Figure 4-1, the first age structure graph for country X shows the percent of the population in each age group for the year 2000. The remaining three graphs are projections of how the age structure of country X will change.
Figure 4-1
11. Using Figure 4-1, what might account for the age structure predicted for the year 2080?
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12. Describe the overall trend in population growth predicted in Figure 4-1.
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13. Referring to Figure 4-1, what can you conclude about the stage of population growth country X is in now?
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14. How is the age structure, as shown in Figure 4-1, expected to change by the year 2015?
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15. In 1980, does country X exhibit an age structure more typical of a developing nation or an industrialized nation? Use Figure 4-1 to explain your answer.
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A student grew a yeast culture on sterilized nutrient medium in a closed dish for five days. Each day, she took the same size sample from the dish and placed it on a special slide used for counting microorganisms (see the top half of Figure 4-2). She examined the samples under a microscope and drew the illustrations of her observations over the course of the investigation. Each dot represents ten yeast cells.
Figure 4-2
16. Which graph (A, B, or C in the bottom half of Figure 4-2) best pictures the growth of the student's yeast population?
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17. Referring to Figure 4-2, what steps could the student take to ensure the accuracy of her results?
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18. In Figure 4-2, how could the carrying capacity of the culture dish be increased?
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19. Looking at the illustrations of the slides in Figure 4-2, how many yeast cells did the student count on Day 1?
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20. In Figure 4-2, how could you estimate the population size of the yeast in Day 3 without counting all the dots in all the squares?
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21. What problem was this student investigating in Figure 4-2?
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22. Why did the student use sterilized medium and keep the dish closed? Refer to Figure 4-2.
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Problem (3 points)
Answer the following using COMPLETE SENTENCES!!!!!
23. Suppose in a population of 1000 wild horses, there are 400 births and 220 deaths. Also, 180 new horses join the population from an area that was destroyed by fire, and 380 horses are captured by park rangers. Describe the overall change in this horse population.
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Figure 4-3 represents a population of bees occupying the same territory in the years 1990 and 1992. Each small block represents 100 bees.
Figure 4-3
24. From Figure 4-3, what was the size of the bee population in 1990?
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25. What is the area of the territory occupied by the bees, according to Figure 4-3?
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26. Observe Figure 4-3 to determine the density per square kilometer of the bee population in 1990.
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27. Referring to Figure 4-3, calculate the change in size and density of the bee population change from 1990 to 1992.
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28. Label the graph in Figure 4-4, which depicts the population growth for a sample of paramecium. Use these terms: initial growth stage, exponential growth stage, leveling-off stage, carrying capacity.
Figure 4-4
29. Are predators a density-dependent or density-independent limiting factor for the population growth of their prey? Explain in complete sentences.
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30. What is the relationship between a population and a species?
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31. Water hyacinth populations double in 6 to 18 days. Introduced in the 1880’s, populations of this plant have clogged major waterways in several states. No predators for it exist in the United States. Does this species have a J-shaped or an S-shaped growth pattern? Explain your choice.
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