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Are humans evolving?. Yes. sexual selection. genetic drift. natural selection. But humans vigorously oppose natural selection. Civilization. Read:. Human populations. Lec 15 2/23/01. Chapter 8. Human populations. Lec 15 2/23/01. World Population Clock.
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Are humans evolving? Yes sexual selection genetic drift natural selection But humans vigorously oppose natural selection Civilization
Read: Human populations Lec 15 2/23/01 Chapter 8
Human populations Lec 15 2/23/01 World Population Clock
World Population: 6,212,638,147 at 10:15 am today births deaths natural increase each month 10,964,310 4,583,441 6,380,869 each day 360,470 150,688 209,782 each hour 15,020 6,279 8,741 each minute 250 105 146
286,486,673 Regional population growth 5.1% of world’s population increasing 0.6% per year doubling time = 117 years
United States Population Picture peaked in 1957 • Baby boom period, following WWII altered age structure of population
Baby Boomers • BB encouraged growth of industries needed by young families. • Today these babies are having babies of their own. • People are now living longer. • By 2030, 20% of US pop will be >65
US pop. Is still growing 1.1% per year. • 0.6% natural increase • 0.5% immigration • Immigration projected to be 50% of U.S. population growth by 2050
286,486,673 Regional population growth 5.1% of world’s population increasing 0.6% per year doubling time = 117 years
Regional population growth 8.44% of world’s population increasing 1.8% per year doubling time = 38 years
Regional population growth 12.9% of world’s population increasing 2.5% per year doubling time = 27 years
Population Age Structure Diagrams rapid growth slow growth decline
Regional population growth 0.5% of world’s population increasing 1.1% per year doubling time = 63 years
Regional population growth 12.3% of world’s population decreasing -0.1% per year
Fig. 7.1 Regional population growth Death rate has increased 30% since 1992 2.5% of world’s population 10% of newborns have birth defects
Regional population growth 60.8% of world’s population increasing 1.5% per year doubling time = 46 years
Natality in 1998 2.1 is replacement fertility
Longevity 78
Longevity 76
72 for females Longevity 59 for men widest gap
Longevity 69
Longevity 68
Longevity 65
Longevity 49
MDC = More Developed Countries LDC = Less Developed Countries • Population • Growth rate
96% of world population growth now occurs in developing regions of Africa, Asia, & Latin America 90% of world’s births and 77% of the world’s deaths now occur in the Less Developed Countries
DEMOGRAPHIC TRANSITION • Demographic Transition: Model of population growth based on historical, social, and economic development of Europe and N. America. • High birth and death rates • then • Death rate falls, population grows • then • Industrialization - birth rate falls • Death rates and birth rates equilibrate • Stable population
Demographic Transition • Comfortable - This is a comfortable model, because it suggests that industrialization will naturally lead to stabilization of the population. • Problem - Can a model developed in Europe and NA be applied to less-developed countries ? Population growth rate is much faster Resources are no longer abundant
Hunger, Food Production and Environmental Degradation • As human population grows so does demand for food. • Most people in developed countries purchase their own food. • Most people in less-developed countries must grow their own food. • Destruction of rainforest and natural areas
3 billion people live on less than $2 a day • Poverty breeds plagues war migration AND population increase