Transcript Human Population Growth

Applying Population
Ecology:
Human Population
Ch. 10
Demography

the study of size, structure, and
make up of human populations.
Demographers study the causes and
important social, health and
economic effects of population
changes.
10-1: Factors Affecting Human
Population Size

Population size depends upon
• birth rates
• death rates
• immigration rates (into area)
• emigration rates (exit area)
Pop. change = (b + i) - (d + e)
Crude Birth and Death Rates


Instead of measuring births/deaths per
year, demographers look at crude birth
and death rates.
Natality- Number of individuals added
through reproduction
Crude Birth Rate - Births per 1000

Mortality - Number of individuals removed
through death
Crude Death Rate - Deaths per 1000
Global Population Change


Death rates have declined, however, not as fast
as birth rates. Therefore, our global population
is still increasing, yet at a slower rate.
More than 82% of the global pop. lives in
DEVELOPING nations!
Annual rate of population change (%) = Birthrate – Death rate x 100
1,000 persons
*In 2004, the global growth rate was 1.25% annually. (~80 M
people)


Most developed countries – 0.1%
Developing countries - ~1.5%
4 ways to calculate a pop. rate of change ( r )
1.
Total births - total deaths/ total population
r = 23,452 -17, 228 = 0.0066 = .66%
942,721
2. birth rate (b) -death rate (d)
r=
25
- 18 = 0.007 =0.7%
1000
1000
3. (Total births + total immigration) - (total deaths + total emigration)
total population
r = (23,452 + 9842)-(17, 228 + 2450) = 0.014 = 1.4%
942,721
4. (birth rate+ immigration rate) - (death rate + emigration rate) x 100
r = (25 + 10) - (18 + 3) = 0.014 = 1.4%
1000
1000
Determining future Pops:
Remember: N (t) = N0ert
N(t) = population after t years
N0 = initial population size
r = growth rate
t = time
Determine the future population
of Duttania:
Remember: N (t) = N0ert
The island of Duttania has 435 people.
Their growth rate is 2%. What will
be the population after 10 years?
A: 531 people.
Population Density
# of indiv. of a species
unit of area
ex. 270,000,000 people = 29 people/Km2 in the US
9,166,605 Km2
Doubling Time

Time to take for a population with a stable
growth rate to double in size
Doubling Time =
td =
70/ r
(growth rate)
Ex. Brazil will double its population in how many
years with the present growth rate of 1.7%?
A: 70/1.7 = 41.2 years
Doubling Time
Demographic Facts:
The nations that will
experience the most
growth over the
next 50 years , in
order:
1.
2.
3.
4.
5.
6.
India
China
Pakistan
Nigeria
Bangladesh
Indonesia
5 most populated
countries, in order:
(2004)
1.
2.
3.
4.
5.
China
India
U.S.
Indonesia
Brazil
Effect of Fertility on Population Growth
Two types of fertility rates affect a country’s
pop. size and growth:
1) Replacement-level fertility (RLF)- number of
children that a couple should have to replace both
parents (Developed countries 2.1 , Some developing
countries 2.5- due to child mortality)
Effect of Fertility on Population Growth continued..
Total fertility rate (TFR) = average number of
children that a woman will have in her
reproductive years (0 - 5+)
2)

•
In 2004, average global TFR was 2.8 / woman. This was a
decline from 5/woman in 1950. (In 2004, Highest TFR was in
Africa with average of 5.2)
Most useful measure of fertility for projecting future
populations.
Global Total Fertility Rates
Population growth
TFR needs to drop to 2.1 in order to stabilize the
population. (Takes into account infant mortality)
*NEED TO REDUCE # OF BIRTHS!
• TFR > RLF = pop growth
• TFR = RLF = steady population
• TFR < RLF = pop slow down
10 Factors affecting Birth rate and Fertility rate
1. Average level of education and affluence
2. Importance of children as a part of the labor force
3. Urban areas (with access to family planning)
4. Cost of raising and educating children
5. Education and employment opportunity for women
6. Infant mortality rate
7. Average age of marriage and 1st child
8. Availability of pension system
9. Availability of legal abortions
10. Birth control/religion
Factors affecting Death rate
Population increase is not necessarily due
only to increased birth rate, but also
decreased death rate.
1. Life expectancy – aver. # of years a newborn is
2.
expected to live
Infant mortality rate = # of babies out of
1000/year who died before their 1st birthday.
Important measure of quality of life since it is linked to so
much of society!
10-2: Population Age Structure
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The age structure diagram sorts the number
of people into groups.
The population is usually divided up into
• Prereproductives (not mature enough to
reproduce)
• reproductives (capable of reproduction)
• Postreproductives (too old to reproduce)

The age structure of a population dictates
whether is will grow, shrink, or stay the
same size.
Age Structure Diagrams
Positive Growth
Pyramid Shape
Zero Growth
(ZPG)
Vertical Edges
Negative Growth
Inverted Pyramid
Be able to identify potential
countries based on diagrams!
10-3: Solutions: Influencing
Population Size
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Controversy over whether govts. should
encourage/discourage pop. growth
• China – 1 child law
• India – limited access to family planning
Family Planning - providing educational and
clinical services that help couples choose how
many children to have and when to have
them.
Demographic Transition Model
1
2
3
4
Preindustrial
Transitional
Industrial
Post- industrial
10-4: Case Studies of
China and India
Population Paradox movie
will cover the details –
so take notes!
10-5: Cutting Global Population Growth
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1994 – UN held conference to encourage action in stabilizing
the global population to 7.8B by 2050, instead of the
projected 8.9B.
180 countries agreed to follow the following guidelines by 2015:
1.
2.
3.
4.
5.
6.
7.
8.
Provide universal access to family planning service and
reproductive health care
Improve health care for infants, children and pregnant women
Develop and implement national pop. Policies
Improve status of women; expand educ. for women and young
girls and job opportunities
Increase the involvement of men in child rearing responsibilities
and family planning
Sharply reduce poverty – famine, disease, etc.
Greatly reduce unsustainable patterns of production and
consumption
Success Stories:
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Thailand – intro on p. 176
Iran – p. 190