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PowerLecture: Chapter 45

PowerLecture: Chapter 45. Population Ecology. Fig. 45-1, p.800. Impacts, Issues: The Numbers Game. St. Matthew Island is an example of how population growth depends on limited environmental resources

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PowerLecture: Chapter 45

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  1. PowerLecture:Chapter 45 Population Ecology

  2. Fig. 45-1, p.800

  3. Impacts, Issues: The Numbers Game • St. Matthew Island is an example of how population growth depends on limited environmental resources • In 1944, US Coast Guard was stationed on the island along with 29 reindeer, as an emergency food supply

  4. The Numbers Game • Without natural predators, reindeer population grew and depleted the island’s lichen • After a harsh winter, all but 1% of the founding herd perished - by the 1980s, no reindeer were left • Today, soaring Whitetail deer populations are overwhelming their environment in North America - damaging the habitat • Principles of Ecology help us understand population dynamics and address population-related problems such as Whitetail deer

  5. How Would You Vote? Are you a supporter of hunting as a way of controlling overpopulation of animals?

  6. Population Ecology What is a Population? Discuss the Human Population Pattern What limits Population Growth?

  7. Fig. 45-2b, p.802

  8. Fig. 45-2c, p.802

  9. Fig. 45-3b, p.803

  10. Determining Population Size • Direct counts are most accurate but seldom feasible • Capture-recapture method is used for mobile species

  11. Fig. 45-4a, p.803

  12. Fig. 45-4b, p.803

  13. Changes in Population Size • What Causes populations to change size? • Limiting Factors • Logistic Growth • Carrying Capacity

  14. Logistic Growth Graph initial carrying capacity new carrying capacity Fig. 45-8, p. 807

  15. Overshooting Capacity • What happens whtn a population overshoots its carrying capacity? Reindeer on St. Matthew’s Island Fig. 45-9, p.807

  16. Density-Dependent Controls • Limiting factors become more intense as population size increases. • What are some density dependent factors?

  17. Density-Independent Controls • Factors unaffected by population density • What would be some D-id controls?

  18. Survivorship Curves Figure 45.11 Page 809

  19. Fig. 45-11a, p.809

  20. Fig. 45-11b, p.809

  21. Fig. 45-11c, p.809

  22. Why are humans living longer now then they used to? Fig. 45-14, p.812

  23. Side-Stepping Controls • Expanded into new habitats • Agriculture increased carrying capacity; use of fossil fuels aided increase • Hygiene and medicine lessened effects of density-dependent controls

  24. Estimated size by 10,000 years ago 5 million By 1804 1 billion By 1927 2 billion By 1960 3 billion By 1974 4 billion By 1987 5 billion By 1999 6 billion Projected for 2050 8.9 billion domestication of plants, animals 9000 B.C. (about 11,000 years ago) beginning of industrial, scientific revolutions agriculturally based urban societies Fig. 45-15, p.813

  25. Resource Consumption • United States has 4.7 percent of the world’s population • Americans have a disproportionately large effect on the world’s resources • Per capita, Americans consume more resources and create more pollution than citizens of less developed nations

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