1. How Has the Human Population Grown Historically
Early Hunter Gatherers
Nomadic, With a Strong Sense of the Earth
Practiced Intentional Birth Control
Rise of Agriculture
Necessary for Survival
Animals became extinct via predation and altered habitat
Humans began to cultivate own food

2. C. Agriculture Gives Rise to Cities
Food Produced in Country, Consumed in City
Food wastes are no longer returned to soil
Soil becomes less productive
Waste of Populations Concentrated in Cities
Population Control in Medieval Societies
Infanticide
Plagues
D. Industrialization
View of Children During Early Phases of Industrial Growth
Valued as cheap source of income and cheap labor
Exponential growth of populations
By 1900s, Birth Rate in Industrialized World Dropped
Rise in standards of living
Safe and inexpensive means of birth control introduced
Increase in the cost of child rearing

4. MI L I O NS

5. Current World Population
Population Clock Vital Events (per time unit)
Global population was 6,379,870,732
On September 1, 2009 at 10:09 am
The global population grows by:
Nearly 2.3 persons per seconds
Nearly 8,343 persons per hour
Over 200,234 persons per day
Over 73 million persons per year

6. How Much is a Billion? 1,000 seconds = 16.7 minutes
1 million-s = 16,677 min = 11.6 days
1 billion-s = 11,574 days = 31.7 years
1,000 pennies = ~ 88 ounces = 5.5 pounds
1 million pennies = 5,500 pounds (~1-Suburban)
1 billion pennies = 2,750 tons (~2 Space Shuttles)

7. Characteristics of a Population
Size: # if individuals in a pop. at any given time
-changes in response to changes in the env, competition and predation
Density: # individuals/area
Age Structure: # of males and females at each age, from birth to death.

8. Human Population Dynamics
There are just three sources of change in population size —
fertility
mortality
"natural decrease" refers to population decline resulting from more deaths than births
migration
Net migration is the number of immigrants minus emigrants

9. Rates of Global Pop. Change use: International Data Base http://www
Rates of Global Pop. Change use: International Data Base then Online Demographic Aggregation
CBR (crude birth rate) = # births / 1000 population
1990: 24 now: 20.6
CDR (crude death rate) = # deaths / 1000 population
1990: 9 now: 8.8
Annual Growth Rate (AGR%) = (b + i) – (d + e)
1990: 1.5% now: 1.19%
growth rates have come down

10. Annual Growth Rate
If you are only given the birth rate and the death rate, the formula is:
AGR %= (birth rate-death rate) x 100
1000 people
OR…AGR%= (birth rate-death rate) 10

13. Doubling Time
Time it takes for a population to double itself, assuming that the current growth rate does not change.
DT=70/AGR%
You may be given the doubling time and asked to calculate the AGR% (EASY MATH!)

14. Overall, the world population is growing at a rate of about 1
Overall, the world population is growing at a rate of about 1.7 per cent; if this rate continues, the population will double in 42 years.
Unabated, such a rate would lead to a point about 2000 years hence when the mass of humanity would weigh more, and be larger, than the Earth.
But, the growth rate is decreasing

15. Maximum Population Growth
W/o influence of biotic (living) and abiotic (non-living) …all populations will have a J curve (exponential)
Environmental Resistance: Organisms cannot reproduce indefinitely because of these factors (shortage of water, light, space, nutrients)
Carrying Capacity (K)=largest population that can be maintained for an indefinite period of time in a specific environment, assuming there are no changes.

16. Carrying Capacity, cont.
Limit to # of organisms is caused by abiotic (light, temp, nutrients, weather, etc)… and biotic (food, prey, disease resistant, adaptable, etc) limiting factors.
Population that is influenced by environmental resistance fluctuates and forms an S shape graph

18. Reproductive Strategies
r- selected species:
many small offspring
little prenatal care
adaptable to unstable climate
high population growth rate
Population size fluctuates wildly above and below carrying capacity (K)
Low ability to compete
small body size

19. Reproductive Strategies
K-selected species:
most live to reproductive age
fewer, larger offspring
low reproductive rate
larger adults/body sizes
lower population growth rate
population size stable and close to carrying capacity (K)
high ability to compete
invest in parental care of young

20. Survivorship
Type I: young don’t die easily; most death occurs at old age (K-strategists)
Type II: RARE-death happens equally at all ages
Type III: death common in early life and only the lucky survive (r-strategists)
These are generalizations and few populations fit one curve exactly.

22. Density Effects on Population
Some environmental events affect populations the same regardless of density=density independent (ex. Earthquakes, fires, bad weather)
Some environmental events affect populations MORE if population is dense= density dependent (population control-ex. Competition for resources, predation, disease, etc)

24. Types of Fertility Rates that Affect Human Population Growth
Total fertility rate (TFR)
The average number of children born to a woman
Average in developed countries = 1.5
Average in developing countries = 3.8
Worldwide 1990: 3.1 now: 2.76
Replacement fertility rate (RFR)
The number of children a couple must have to replace themselves
A RFR of 2.1 for developed countries with low infant and child mortality rates
Africa RFR = 2.5

26. Factors that Affect Death Rates
1. Life Expectancy: avg. # of years to be lived by a person in the same country (good measure of quality of life)
2. infant mortality rate: IMR
infant deaths per 1000 live births (infant < 1 yr)
1990: 62 now: 52.4 (normal in 1900: 200)
** # 1 cause of population increase is DEATH RATE, not increased births!

27. http://www. povertymap

28. Migration
Net migration is the number of immigrants minus emigrants

30. Population Pyramids Graphic device: bar graph
shows the age and gender composition of a region
horizontal axis: gender
male: left-hand female: right-hand
absolute number of people or %
vertical axis: age
5-year or 10-year age groups

31. Population Pyramid with young cohorts

32. Population Pyramids High Growth: Afghanistan
Population Pyramids on the Web
High Growth: Afghanistan
Moderate Growth: Mexico
Zero Growth: U.S.
Negative Growth: Austria or Italy

37. Demographic Transition
Movement of a nation from high population growth to low population as it develops economically
Transition as a result of four stages
Stage 1—Birth and death rates are both high
Stage 2—Death rates fall; birth rates remain high; growth rate rises
Stage 3—Birth rates fall as standard of living rises; growth rate falls
Stage 4—Growth rate continues to fall to zero or to a negative rate

38. The Demographic Transition
                                                                                                                                                                

40. Five Stages of the Demographic Transition
Used to be 4, now 5 stages
birth rates, death rates and growth rates systematically change through time as societies change:
modernize, urbanize
gain access to technology

41. Stage 1
high birth rates, high (at time erratic) death rates, low growth rates
stage for much of human history, traditional societies
practically no country today

42. Stage 2 high birth rates, declining death rates, rising growth rates
improvements in
sanitation (water)
and medicine
in Europe during Industrial Revolution
in developing countries since the 50s/60s
much of Africa today, some countries of Asia (Afghanistan, Nepal, etc.)

43. Stage 3 continued decline of death rates, declining birth rates,
growth rates decline from
high to lower levels
change in behavior: adaptation to lower death rate, in particular infant mortality rate
economic change: urbanization (incentive to have fewer children)
Mexico today

44. Stage 4 & 5 Stage 4: low birth rates, low death rates, low
growth rates
United States today
Stage 5: low birth rates, rising death rates, declining growth rates (if birth rates drop below death rates: negative growth rates)
several countries of Europe today (Austria)

46. Demographic Trap
Population Path of Most Less-Developed Countries (LDCs)
“Trapped” in Stage 2 of Demographic Transition
Before 1970, LDCs seemed poised to make transition thanks to economic growth
Since 1970, economic growth has not kept pace with population
High birth and low death rates result in explosive population growth
Downward spiral in standard of living

47. Demographic Fatigue
Condition characterized by a lack of financial resources and an inability to deal effectively with threats such as natural catastrophes and disease
Possibility that countries suffering from demographic fatigues could slip back into Stage 1 of demographic transition

48. Age Structure & Population Projections
Baby boomers - half of U.S. population; use most of goods and services; make political and economic decision
baby-bust generation - born since 1965; may have to pay more income, health care and social security to support retired baby boomers; but face less job competition
Better health --> later retirement of baby boomers --> keep high-salary jobs=less higher paying jobs for others

49. Tracking the baby-boom generation in the United States

50. Effects of Population Decline
As percentages of 60+ aged people increases, population begins decline
60+population increase --> severe economic and social problems because 60+ consume
more medical care
Social Security
costly public services
Labor shortages require automation & immigration

51. Cutting Global Population Growth
U. N.Conference on Population and Development, Cairo, 1994
8 goals to be met by 2015 (p. 276)
are these goals wishful thinking?
Replacement level fertility can be met in years as shown by Japan, Thailand…
Invest in family planning, reduce poverty, and elevate status of women

52. What Is Family Planning?
Definition
Measures enabling parents to control number of children (if they so desire)
Goals of Family Planning
Not to limit births
For couples to have healthy children
For couples to be able to care for their children
For couples to have the number of children that they want

54. China’s Program
Nation With Best Known Population Control Program
Reasons Chinese Government Initiated Population Control Measures
Freshwater and food at a premium for nation’s population
Country experiencing population momentum
Government Perks / Coercive Measures for Citizen Compliance
Free education and health care
Increased personal and family incomes
Increased legal marrying age for women
Contraceptives, abortions, and sterilizations free of charge
Preferential housing and retirement income

55. Issues with Large World Population
We may exceed the K for humans-poplulation and individual consumption determine the K for humans.
World Hunger: highest TFR have the greatest hunger (usually)
-800 million hungry, some starve to death (S. Asia and sub-Saharan Africa)
-Enough food made for all, but unevenly distributed (some too poor to grow or buy)
-Can control population growth & promote economic development in these countries

56. Issues with Large World Population
Economic Effects: stable population promotes economic development
-economy must grow at least as fast as the population for standard of living to improve
Resource Consumption: country is overpopulated if level of demand on its resource base is damaging to the environment
-People Overpopulation: environmental degradation because too many people, even though individual resource use is small

58. Issues with Large World Population
-In developed countries, resource use/person is huge and deplete world’s resources with “consumptive” lifestyle (but we also use technology to find alternatives: ex. plastics for metal)
Urbanization: people increasingly concentrated in cities (47%)=urbanization worldwide
-developed country: not experiencing as much urban growth as developing (Bombay & Shanghai)
-developing countries grew so fast that they formed shantytowns around the city with no sanitation or water.

59. -Many homeless in cities in developing countries (250,000 in Calcutta, India vs. 300, ,000 in ALL US cities)
-Solution: Compact development (SMART growth)=compact, high density housing next to mass transit, jobs, shopping (ex. Portland, OR)

61. Solutions: Influencing Population Size
Reduce the TFR (culture, religion, etc)
Elevate the status of women (education, marriage age)
Family Planning
Governmental Policies (economic incentives or penalties)