4. • Understanding of set of processes underlying
• Births,
• Deaths,
• Movement into and out of given population
• Describing change in
• Fertility,
• Mortality,
• Migration
• Understanding what might be causing changes
5. MANIFEST functions of a social pattern
outcomes people consciously intend or
predict from the actions they choose
the explanations they give themselves
LATENT functions of a social pattern
the outcomes that regularly occur but are
neither foreseen or intended.
must be discovered through research
POPULATION dynamics stem from BOTH
6. LATENT
Polygyny
Dowry (economic)
Marry late (age)
Taboos about
non-marital sexual
intercourse
Higher divorce rates
Religious bans
(180 days/year)
Breastfeeding
MANIFEST
Potions, spells, etc.
Since 1850 B.C., barrier
methods of
contraception used
Coitus interruptus
Abortion
Infanticide
(c.f. story of Moses...)
7.
8. Core Concept: Demographic transition
• Initial pretransition period:
• high fertility
• high mortality
• Transitional period
• mortality first declines
• followed by decline in fertility
• Posttransition period
• both fertility and mortality are low
9.
10. Sudan-1950
Start of first demographic transition
Rapid decreases in mortality, but much later
and slower decreases in fertility, which in turn
imply very rapid population growth
U.S.
End of first demographic transition
Age pyramid after age 60
Replacement fertility
Japan
Completed first demographic transition
Below replacement fertility
11.
12. Immigration
• U.S.: Population involves in- and out-migration
• Japan: Very small immigrant population
Population momentum
• U.S.: Continued slow growth
• Japan: Initial and then decreased growth
13. Baby Boom bulge in middle of pyramid.
Long lives means many more elderly in future years.
14. First demographic transition
• Impacts kinds of disease and health conditions affecting
countries
Epidemiological transition
• Healh transition of population
• from health conditions primarily involving infectious disease
• to health conditions primarily involving chronic disease
15.
16. 16
Why 40-44?
First bar = 1976
(What year were these
women 20 years old?)
Last bar = 1998
(What year were these
women 20 years old?)
What pattern?
20. This pattern is very likely, unless something occurs that causes the
death rate of the elderly to increase dramatically.
Source: United Nations FPA: Ageing in the Twenty-First Century: A Celebration and A Challenge
http://www.unfpa.org/webdav/site/global/shared/documents/publications/2012/UNFPA-Main-Report-Part2.pdf
21. Will some countries age more quickly than others?
Japan (if fertility remains at very low subreplacement levels)
• Rapid population aging
• Rapid population decline
Demographic Winter (Friday’s film) will report fertility figures for
some of European countries that are well below 2.0, some as low
as 1.1 children per woman (population will be half its current
size in 33 years).
22. This pattern is somewhat less certain. No nation has ever reversed the
decline in birth-rate. However, governments in Japan, Russia and Sweden
are trying to boost their birth rates. Such policies might have an impact.
24. Some social scientists have great concern that
population decline will have economic and social
consequences that will be hard to live with. They
produced a film titled Demographic Winter.
25. What are the patterns of childbearing?
What are the economic impacts?
What are the social trends that generated
and sustain the pattern?
Is this a problem?
If so, what policies are needed?
26. The search for causes is seeking explanation
If the situation is considered a problem,
the resolution is not necessarily the reversal of
the original circumstances.
Example: Obesity is a growing problem because we
have more, cheaper food than any time in history. No
one suggests going back to less efficient agriculture to
cure obesity – but other policies do try to have an
impact on the problem.
The facts in the film are solid. It is designed to
be provocative so that people think.
Nations and regions do not return to pretranstion levels of high fertility.
Definition:Population momentum: Tendency of population that has been changing in size to continue to change in size even if factors such as fertility and mortality have shifted to levels that would, in the long run, imply no change in population size.
Baby boomers: Persons born between 1946 and 1964Reflection of the baby boom in the children of the baby boomers in U.S.Peak for the children of Japan’s baby boomers sharper than in U.S.
DefinitionsEpidemiology: Study of health-related events in populations, their characteristics, their causes, and their consequences.
Pace of population growth and pace of population aging are fundamentally questions involving population dynamics.