Transcript 22Population

Population
© Robert J. Atkins, Ph.D.
What are six basic demographic
(population) terms?
 Demography
The
study of human population
 Fertility
Amount
of childbearing in a
population
Several measurements of this
Demographic terms (cont.)
 Crude
birth rate
Live births per 1,000 people each
year
High income nations e.g. U.S. =
lower than average crude birth rate
The lower the average income, the
higher the population increase
Demographic terms (Cont.)
 Fecundity
rate
Maximum possible childbearing
 Sex Ratio
Males for every 100 females
 Zero Population growth (ZPG)
Two
people produce two people
Maintains population at a steady state
Do you remember?
What are the six basic demographic
terms?
 What do they measure?

What is the
world population?
 Currently
7
Billion
 Most
of human history the
population of the entire earth was
500 Million (1/2 billion)
Something to think about:
Why do developing nations contribute so much more
to the world population?
Why do people have so
many children?
 Through
Birth
most of human history:
control was not reliable
Children were needed for the farm
High death rates = many children did not
reach adulthood
What is the
Malthusian theory?
 Food
increasing arithmetically
 Pop. Increasing geometrically
 Result : People reproducing
beyond what the planet can
support
Out-stripping
resources
Poisoning the planet
What is the Malthusian theory?
Population
increases
geometrically
Food increases
arithmetically
Population could
increase beyond
what the planet
could support
Population
Food
What is the Demographic
Transition Theory?




Population patterns reflect
a society’s level of
technological development
From preindustrial (high
births & deaths) = slow
population growth
To postindustrial (low births
& deaths) = slow or stable
population growth
Between these two, high
birth rate & low death rate
= rapidly expanding
population
Do you remember?
What is the current world population?
 Why did people have so many children?
 What is the Malthusian theory?
 What is the Demographic Transition
theory?
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