1. Human Populations
02 June 2010
Human-Populations.ppt 1

2. Human populations grow slowly
K-selected, Equilibrium species
Few large offspring
Parental care
lasting > 10 yrs.
Birth interval 2-5 years in most of world.
02 June 2010
Human-Populations.ppt 2

3. Human population growth
Historic growth
Exponential growth in recent times.
Carrying capacity? How much can human populations grow?
02 June 2010
Human-Populations.ppt

4. Human population growth
Δ N = +B +I –D –E
B = birth rate = live births/1000 people/year
D = death rate = deaths/1000/year   If B > D, population grows
For most of human history B = D
02 June 2010
Human-Populations.ppt 4

5. Human Impact IPAT model I = P x A x T I = P x A x T x S I = impact
P = population size
A = affluence
T = technology
I = P x A x T x S
S = sensitivity
02 June 2010
Human-Populations.ppt 5

6. Demography Population size Population density and distribution
Age structure
Sex ratios
02 June 2010
Human-Populations.ppt

7. Demography Population density and distribution 02 June 2010
Human-Populations.ppt

8. Demography Age structure Sex ratios Slow growth vs. Rapid growth
02 June 2010
Human-Populations.ppt

9. Demography Age structure Sex ratios China’s One-child policy
02 June 2010
Human-Populations.ppt

10. Age structure of USA Effect of “baby-boom” generation
Baby-boomers now in most productive years;
Soon to retire and draw Social Security;
Soon to suffer medical needs of older age, need for nursing homes, hospitals, medical doctors;
Needs MUST be met by smaller population of offspring.
02 June 2010
Human-Populations.ppt

11. Human Population I = P x A x T Population size Affluence Technology
02 June 2010
Human-Populations.ppt

12. Human Population “Fertility rate” Replacement fertility rate
Average number of children per female (lifetime)
Replacement fertility rate
Δ N = +B +I –D –E
02 June 2010
Human-Populations.ppt

13. Demographic transition
02 June 2010
Human-Populations.ppt

14. Demographic transition
Birth/Fertility rates have changed.
Fertility:
Total fertility rate
Number of children a woman produces in childbearing years
Replacement-level fertility
Number of children necessary to replace parents,
To maintain constant population size
~ 2.1 per woman
02 June 2010
Human-Populations.ppt 6

15. Demographic transition
Empowerment of women
Rising standard of living
Education influences fertility rate
02 June 2010
Human-Populations.ppt

16. Demographic transition
Empowerment of women
Family planning
Availability of contraception
02 June 2010
Human-Populations.ppt

17. Demographic transition
Factors affecting birth/fertility rates:
Children in labor force,
Urbanization,
Cost of raising & educating,
Opportunities for women,
Age at marriage,
Infant mortality,
Available contraception & abortion,
Religious & cultural values.
02 June 2010
Human-Populations.ppt 7

18. Infant mortality decline
Improved food supply
Proper nutrition (vitamins, protein, fats)
Control of infectious disease.
Influenza
Diphtheria
Polio
Malaria
& more
02 June 2010
Human-Populations.ppt 9

19. Infant mortality decline
Infant death for full term babies now rare in USA, N. Europe.
Contrast to 19th century.
Darwin’s children (born 1840’s)
Enrico Caruso (1873 – 1923).
02 June 2010
Human-Populations.ppt

20. Recently, Have death rates changed? Life expectancy increased
Increased food supply, better nutrition
Sanitation/ personal hygiene
Medical care (immunization, antibiotics)
Safe water supplies
Decrease in infant mortality.
02 June 2010
Human-Populations.ppt 8

21. Demography Predicting the future of populations:
Age structure diagrams
People age !
Fertility rate
Death rate
(age specific death rates)
02 June 2010
Human-Populations.ppt