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Populations

Populations. OVERVIEW. Population: all the individuals of one species in a given area HOW POPULATIONS GROW Exponential vs. logistic r VS. K Carrying Capacity Human Population Statistics Predictions Impact on Conservation. Exponential Growth.

theodore-weeks
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Populations

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  1. Populations

  2. OVERVIEW • Population: all the individuals of one species in a given area • HOW POPULATIONS GROW • Exponential vs. logistic • r VS. K • Carrying Capacity • Human Population Statistics • Predictions • Impact on Conservation

  3. Exponential Growth • Biotic Potential – Pop. Grows as fast as physiology allows. • Unlimited resources • No pollution build up • Ideal conditions • Short lived period • Often quickly die out, colonize new areas • R selected species Population size (N) Time (t) Exponential Growth Fig. 9.4, p. 201

  4. Logistic Growth K • Slower initial growth • Long –term stable pop. At carrying capacity (K). • K is size of pop. Area can sustain. • Growth slowed by limiting factors Population size (N) Time (t) Logistic Growth Fig. 9.4, p. 201

  5. Environmental Resistance Carrying capacity (K) Population size (N) Biotic Potential Exponential Growth Time (t) Fig. 8-3, p. 163

  6. Overshoot Carrying capacity Number of sheep (millions) Year Fig. 8-4, p. 164

  7. Late loss Constant loss Percentage surviving (log scale) Early loss Age Fig. 8-11, p. 169

  8. Reproductive Patterns • r-selected species tend to be opportunists while K-selected species tend to be competitors. Figure 8-10

  9. Population overshoots carrying capacity Population Crashes Number of reindeer Carrying capacity Year Fig. 8-6, p. 165

  10. Hare Lynx Population size (thousands) Year Fig. 8-7, p. 166

  11. 5,000 Moose population Wolf population 4,000 3,000 Number of moose 100 90 80 2,000 70 60 Number of wolves 50 40 1,000 30 20 500 10 0 1900 1910 1930 1950 1970 1990 2000 Year 1997 Fig. 9.9, p. 204

  12. 16 15 ? 14 13 12 11 ? 10 9 Billions of people 8 ? 7 6 5 4 3 2 Black Death–the Plague 1 0 2-5 million years 8000 6000 4000 2000 2000 2100 Time B.C. A.D. Fig. 1.1, p. 2 Hunting and gathering Agricultural revolution Industrial revolution

  13. Average crude birth rate Average crude death rate 21 World 9 All developed countries 11 10 All developing countries 23 8 Developing countries (w/o China) 27 9 Fig. 9-3, p. 174

  14. Births per woman < 2 4-4.9 2-2.9 5+ Data not available 3-3.9 Fig. 11.8, p. 242

  15. 38 Africa 15 Latin and Central America 21 6 20 Asia 7 Oceania 17 7 United States 14 8 North America 14 8 Europe 10 11 Fig. 9-3, p. 174

  16. 1.3 billion China 1.5 billion 1.1 billion India 1.4 billion USA 300 million 349 million Indonesia 225 million 264 million 187 million Brazil 229 million Pakistan 166 million 229 million Bangladesh 147 million 190 million Russia 142 million 130 million Nigeria 135 million 199 million Japan 128 million 121 million 2025 2006 Fig. 9-4, p. 174

  17. GNP per capita, 1998 Low income (Under $1,000) Middle income ($1,000–$10,000) High income (Above $10,000) Fig. 1.5, p. 9

  18. Births per woman Replacement Level Baby boom (1946–64) Year Fig. 9-5, p. 175

  19. 47 years Life expectancy 77 years 8% Married women working outside the home 81% 15% High school graduates 83% 10% Homes with flush toilets 98% 2% Homes with electricity 99% 10% Living in suburbs 52% 1900 Hourly manufacturing job wage (adjusted for inflation) $3 2000 $15 1.2 Homicides per 100,000 people 5.8 Fig. 9-7, p. 176

  20. 1907 1914 New laws restrict Immigration Number of legal immigrants (thousands) Great Depression Year Fig. 9-8, p. 178

  21. Male Female Female Male Female Male Male Female Expanding Rapidly Guatemala Nigeria Saudi Arabia Expanding Slowly United States Australia Canada Declining Germany Bulgaria Italy Stable Spain Portugal Greece Reproductive ages 15–44 Postreproductive ages 45–85+ Prereproductive ages 0–14 Fig. 9-9, p. 179

  22. Age Age Age Age Males Females Females Females Males Males Females Males 1955 1985 2035 2015 Fig. 9-11, p. 180

  23. Percentage of world population India 17% China 20% 1.1 billion Population 1.3 billion 1.4 billion Population (2050) (estimated) 1.6 billion 47% Illiteracy (% of adults) 17% 36% Population under age 15 (%) 20% 1.6% Population growth rate (%) 0.6% 2.9 children per women (down from 5.3 in 1970) Total fertility rate 1.6 children per women (down from 5.7 in 1972) 58 Infant mortality rate 27 62 years Life expectancy 70 years Percentage living below $2 per day 80 47 $3,120 GDP PPP per capita $5,890 Fig. 9-15, p. 186

  24. Human-Dominated Systems Property Natural Systems Complexity Energy source Waste production Nutrients Net primary productivity Biologically diverse Renewable solar energy Little, if any Recycled Shared among many species Biologically simplified Mostly nonrenewable fossil fuel energy High Often lost or wasted Used, destroyed, or degraded to support human activities Fig. 9-16, p. 188

  25. Natural Capital Degradation Altering Nature to Meet Our Needs Reduction of biodiversity Increasing use of the earth's net primary productivity Increasing genetic resistance of pest species and disease-causing bacteria Elimination of many natural predators Deliberate or accidental introduction of potentially harmful species into communities Using some renewable resources faster than they can be replenished Interfering with the earth's chemical cycling and energy flow processes Relying mostly on polluting fossil fuels Fig. 9-17, p. 188

  26. Human Population growth • For most of our history a logistic curve. • Currently exponential growth • Not uniform around the globe • Developing nations growing fastest • What has made the change possible? • Drop in death rate. Birth rate has fallen, not increased. • How long will this be sustainable? • Future predictions for growth?

  27. Infant deaths per 1,000 live births <10 10-35 36-70 71-100 100+ Data not available Fig. 11.14, p. 246

  28. Annual world population growth <1% 1-1.9% 2-2.9% 3+% Data not available Fig. 11.3, p. 240

  29. 2.5 2.0 1.5 Growth rate (percent) 1.0 0.5 0.0 1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050 Year Fig. 11.4, p. 240

  30. China 1.26 billion 1.4 billion India 1 billion 1.4 billion USA 276 million 338 million Indonesia 212 million 273 million Brazil 170 million 221 million Pakistan 151 million 227 million Russia 145 million 137 million Bangladesh 128 million 177 million Japan 127 million 121 million Nigeria 123 million 205 million Fig. 11.5, p. 241 2000 2025

  31. Asia 3.7billion 4.7 billion Europe 728 million 714 million Africa 800 million 1.3 billion Latin America 518 million 703 million North America 306 million 374 million Oceania 31 million 39 million Fig. 11.6, p. 241 2000 2025

  32. 4.0 3.5 3.0 2.5 Births per woman 2.1 2.0 1.5 1.0 0.5 0 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year Total fertility rates in USA 1917-2000 Baby Boom (1946-64) Below replacement rate- immigration keeps population growing Fig. 11.10, p. 243

  33. Birth Control Methods: Highly Effective Extremely Effective Total abstinence IUD with slow-release hormones 98% 100% Sterilization IUD plus spermicide 98% 99.6% Hormonal implant (Norplant) Vaginal pouch (“female condom”) 97% 98% IUD 95% Condom (good brand) plus spermicide 95% Oral contraceptive 93% Fig. 11.12a, p. 244

  34. Effective Moderately Effective Spermicide (creams, jellies, suppositories) Cervical cap 89% 75% Condom (good brand) Rhythm method (daily temperature readings) 74% 86% Diaphragm plus spermicide 74% Withdrawl 84% Condom (cheap brand) Rhythm method (Billings, Sympto-Thermal) 70% 84% Vaginal sponge impreg- nated with spermicide 83% Spermicide (foam) 82% Unreliable Douche 40% Chance (no method) 10% Fig. 11.12b, p. 244

  35. Developed Countries 50 40 Rate of natural increase 30 Rate per 1,000 people Crude birth rate 20 Crude death rate 10 Rate of natural increase = crude birth rate = crude death rate 0 1800 2000 1775 1850 1900 1950 2050 Fig. 11.13a, p. 245 Year

  36. Developing Countries 50 Crude birth rate 40 Rate of natural increase 30 Rate per 1,000 people Crude death rate 20 10 0 1800 2000 1775 1850 1900 1950 2050 Fig. 11.13b, p. 245 Year

  37. 110 100 90 80 70 Deaths under age 1 per 1,000 live births 60 50 40 30 20 10 0 1920 1930 1940 1950 1960 1970 1980 1990 2000 Years Fig. 11.15, p. 246

  38. Demographic transition • Death rate ( infant mortality) drops first. • Birth rate remains constant • Population increase quickly • Economy transitions from agriculture to urban. • Larger families cost more, birth rate drops. • Population. Now much larger slows its growth rate. • Influence of other (cultural, religious) pressures • Women often lack freedom to determine family size, education employment opportunities

  39. Stage 1 Preindustrial Stage 2 Transitional Stage 4 Postindustrial Stage 3 Industrial High Birth rate Relative population size Birth rate and death rate (number per 1,00 per year) Death rate Total population Low Low Negative Increasing Zero Low Very high Decreasing Growth rate over time Fig. 9-14, p. 183

  40. Births per thousand population End of World War II Demographic transition Depression Baby boom Echo baby boom Baby bust Year Fig. 9-6, p. 175

  41. Some predications • Will technology save us? • The soft landing – no population collapse • Will we have a crash after we have exceeded our carrying capacity? • No one knows

  42. 12 11 High High 10.7 10 Medium Low 9 Medium 8.9 8 Population (billion) 7 6 Low 7.3 5 4 3 2 1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050 Fig. 11.9, p. 242 Year

  43. 40 35 30 25 Age Distribution (%) 20 15 10 5 0 1950 1970 1990 2010 2030 2050 2070 2090 2110 2130 2150 Year Fig. 11.22, p. 249 Age 60 or over Age 80 or over Under age 15

  44. Population Industrial output Pollution Food Resources State of the World 1900 2000 2100 Year Fig. 11.24a, p. 251

  45. State of the World 1900 2000 2100 Year Population Industrial output Pollution Food Resources Fig. 11.25a, p. 254

  46. Influence on environment • More land fro agriculture, resource exploitation • More land for cities, roadways, suburbs • Less fish in the sea for the food chain • Deforestation • Oil, gas won’t last forever • Pollution builds up • Better “green” technologies? • Heightened awareness, concern? • Better understanding of ecosystems?

  47. Arctic Circle Arctic Circle Tropic of Cancer Equator Tropic of Capricorn Human disturbance Antarctic Circle Predominantly natural Partially disturbed Human dominated Fig. 1.4, p. 8

  48. 12 11 10 World total 9 8 Developing countries 7 Population (billions) 6 5 4 3 Developed countries 2 1 2050 2000 1950 2100 Year Fig. 1.6, p. 9

  49. Per Captia Ecological Footprint (Hectares of land per person) Country 10.9 United States 5.9 The Netherlands 1.0 India Fig. 1.10a, p. 11

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