1. Copyright © 2005 Pearson Prentice Hall, Inc. Chapter 39 Population Growth and Regulation

3. Copyright © 2005 Pearson Prentice Hall, Inc. How Does Population Size Change? Biotic Potential Can Produce Exponential Growth –Exponential growth curves are J-shaped (F39.1 p. 800) –The effect of death rates on population growth (F39.2 p. 801)

4. number of individuals time (minutes) time (years) Reproduction begins at 6 years bacteria eagles (i) (ii) timenumber of (minutes)bacteria 01 202 404 608 8016 10032 12064 140128 160256 180512 2001024 2202048 timenumber of number of (years)eagles (i)eagles (ii) 022 222 442 684 8148 102812 125216 1410032 1619054 1836286 20630142 221314238 242504392 264770644 2890881066 30173141764

5. number of individuals time (minutes) bacteria timenumber of (minutes)bacteria 01 202 404 608 8016 10032 12064 140128 160256 180512 2001024 2202048

6. number of individuals time (years) Reproduction begins at 6 years timenumber of number of (years)eagles (i)eagles (ii) 022 222 442 684 8148 102812 125216 1410032 1619054 1836286 20630142 221314238 242504392 264770644 2890881066 30173141764 (i) (ii)

7. number of individuals time (years) Reproduction begins at 6 years timenumber of number of (years)eagles (i)eagles (ii) 022 222 442 684 8148 102812 125216 1410032 1619054 1836286 20630142 221314238 242504392 264770644 2890881066 30173141764 (i) (ii)

8. no deaths number of individuals time (hours) bacteria 10% die between doublings 25% die between doublings

9. Copyright © 2005 Pearson Prentice Hall, Inc. How Is Population Growth Regulated? Exponential Growth Cannot Continue Indefinitely –A boom-and-bust population cycle (F39.3 p. 801) –Lemming population cycles follow a boom- and-bust pattern (F39.4 p. 801)

10. population density

11. approximate number of lemmings per acre

12. Copyright © 2005 Pearson Prentice Hall, Inc. How Is Population Growth Regulated? Environmental Resistance Limits Population Growth –The S-curve of population growth (F39.5 p. 803) –The effects of exceeding carrying capacity (F39.6 p. 804)

13. carrying capacity time exponential growth: J-curve (environmental resistance) equilibrium (biotic potential) number of individuals

14. exponential growth population crash year number of reindeer 0 500 1000 1500 2000 19101920 19301950 1940

15. Copyright © 2005 Pearson Prentice Hall, Inc. How Is Population Growth Regulated? –Density-Independent Factors Limit Populations Regardless of Their Density –Density-Dependent Factors Become More Effective as Population Density Increases –Predators and Parasites Exert Density- Dependent Controls on Populations Predators help control prey populations (F39.7 p. 805)

16. Copyright © 2005 Pearson Prentice Hall, Inc. How Is Population Growth Regulated? –Competition for Resources Helps Control Populations Emigration (F39.8 p. 806)

18. Copyright © 2005 Pearson Prentice Hall, Inc. How Is Population Growth Regulated? Survivorship in Populations Follows Three Basic Patterns –Survivorship curves (F39.9 p. 807)

19. 1000 100 10 0 number of survivors age (in percentage of maximum life span) early loss (dandelion) constant loss (American robin) late loss (human)

20. Copyright © 2005 Pearson Prentice Hall, Inc. How Is the Human Population Changing? The Human Population Is Growing Rapidly –Human population growth (F39.10 p. 808)

21. Technical and cultural advancesAgricultural advances Industrial and medical advances bubonic plague billions of people 7 6 5 4 3 2 1 0 2003 1999 1987 1975 1960 1930 1830 12,00011,00010,000 9000 80007000600050004000300020001000 B.C./A.D. 10002000 B.C. B.C. B.C. B.C. B.C. B.C. B.C. B.C. B.C. B.C. B.C. B.C. A.D. A.D.

22. Copyright © 2005 Pearson Prentice Hall, Inc. How Is the Human Population Changing? Technological Advances Have Increased Earth’s Carrying Capacity for Humans – Unnumbered Figure 1 (p. 809) – Unnumbered Figure 2 (p. 809)

23. time death rate natural increase birth rate Demographic transition birth and death rate

24. 2003: 6.3 billion developing countries developed countries 10 8 6 4 2 0 population (billions) 195019701990201020302050

25. Copyright © 2005 Pearson Prentice Hall, Inc. How Is the Human Population Changing? The Age Structure of a Population Predicts Its Future Growth (F 3 p. 810) –Age structures compared (F39.11 p. 810) –Population change by world regions (F39.12 p. 811)

26. expanding stable shrinking postreproductive (46–100 years) reproductive (15–45 years) prereproductive (0–14 years)

27. Developed countries 20032025 postreproductive (45–79 yr) reproductive (15–44 yr) prereproductive (0–14 yr) millions of people age Developing countries (a) (b) 80 70 60 50 40 30 20 10 0 80 70 60 50 40 30 20 10 0 320280240200160120804004080120160200240280320

28. World average 1.3% Developing countries 1.6% World regions annual natural increase Africa 2.4% Latin America/Caribbean 1.7% Asia (excluding China and Japan) 1.6% Developed countries 0.1% China 0.6% N. America 0.5% Europe –0.2%

29. Copyright © 2005 Pearson Prentice Hall, Inc. How Is the Human Population Changing? The United States Population Is Growing Rapidly –U.S. population growth (F39.13 p. 812) –Population cycles in predators and prey (FE39.1 p. 802) –Experimental predator–prey cycles (F E39.2 p. 802) –Deforestation can lead to the loss of productive land (FE39.3 p. 813)

30. U.S. population (in millions) (1790–2003) year

31. abundance of lynx (  1000) abundance of hares (  1000) year hares (prey) lynx (predator)

32. adult population generation bean weevils (prey) branconid wasp (predator)