Transcript Population - Decatur Public Schools / Overview

POPULATION
Bell Work – Population & Demography 2/3
What does this graph show?
What is the message of this political cartoon?
What happened between 1600 & 1900 that could have cause the
population to increase so dramatically?
3 REASONS STUDYING
POPULATION IS CRITICAL
More people are alive today than at any other time in
human history
The world’s population increased at a faster rate during
the second half of the twentieth century than every
before.
Virtually all population growth today occurs in less
developed countries (LDCs)
QUESTIONS TO ASK
ABOUT POPULATION
Why is the population growing so quickly?
Which areas are growing fastest?
What effects has this growth had on social and ecological systems?
What can we expect from future growth?
These questions = Population Geography also known as
Geodemography
The study of human populations = demography
THE PROBLEM IS THAT POPULATION IS
LIKE COMPOUND INTEREST
Lets say you invest a $1,000,000 in a bank account that is guaranteed a
minimum of 3% interest
The next year you would then have $1,030,000
And the next year you would have $1,060,900
And the next $1,092,727
$25 years… later $2,088,626.81
With a 3% growth rate the U.S population would double by then time you were
42 which means 300,000,000x2= 600,000,000
If the population of the U.S doubles what else needs to double?
What are some reasons this probably won’t happen here?
The actual growth rate is .7
However! The growth rate in Africa, the Middle East & Central America
are all above 3%
WHERE IS THE WORLD’S
POPULATION DISTRIBUTED?
Population concentrations
• Two-thirds of the world’s population are in four
regions:
•
•
•
•
East Asia (1/4 of world pop, 5/6 of this in China)
South Asia (1/4 of world pop, ¾ of this in India)
Europe (1/9th of the world pop, mostly in cities)
Southeast Asia (600 million, mostly in islands)
• 80% of the worlds population lives in LDCs
• Not to mention that over the past 50 years the global
life expectancy has increased from 45 to 65 years
CARTOGRAMS
Cartograms are not usually useful for exact measures of
population, however they do illustrate the point clearer than
some other maps (think of the ones you did a while back with
the substitute
What’s the difference in terms of concentration & density of china
compares to the U.S?
WHERE IS THE WORLD’S
POPULATION DISTRIBUTED?
Sparsely populated regions
• The ecumene (portion of the world’s surface occupied by
permanent human settlement)
• People generally avoid:
•
•
•
•
Dry lands
Wet lands
Cold lands
High lands
WHERE IS THE WORLD’S POPULATION DISTRIBUTED?
Population density
Arithmetic density – the number of people living in a given area
• Most frequently used
• More accurate the smaller the area observed
• Tells us WHERE, but not WHY people live in an area (we must have more info for
that)
Physiological density
- A ratio of human population to
the area of arable land
• The greater the physiological
density, the more stress those
people put on the land to
produce crops
• Gives us insight as to the
available resources of an area
• If you compare the arithmetic
density to the physiological
density, you can infer how
much of the area’s land is
unsuitable for agriculture
Physiologic
Population Density
Luxor, Egypt.
Egypt’s arable
lands are along the
Nile River Valley.
Moving away from
the river a few
blocks, the land
becomes sandy and
wind-sculpted.
Agricultural density – ratio of the number of
farmers/arable land
•
•
•
High # of farmers=low technology
Low # of farmers=high technology
Comparing Physiological to Agricultural density shows the
relationship between the population of a country and its
resources
POPULATION
KEY ISSUE #2 – WHERE HAS THE WORLD’S
POPULATION INCREASED?
NATURAL INCREASE
Crude Birth Rate (CBR) = Total # of births in a year for every 1,000
Crude Death Rate (CDR) = Total # of deaths a year for every 1,000
Natural Increase Rat (NIR) =% by which a population grows each year
CBR-CDR=NIR
What affects a nations natural increase?
Economic development
Education
Gender Empowerment
Healthcare
Cultural Traditions
Public Policy
To predict how much a population will grow we use the demographic
accounting equation
The Demographic Accounting Equation
Pop(t+1) = Pop(t) + B – D + MI - Mo
Pop(t+1) = Population in time t+1, the year following
the current year.
Pop(t) = Population in time t, the current.
B
= Births
D
= Deaths
MI
= In-migrants
Mo
= Out-migrants
• (B-D) = Natural Increase
• (MI-MO) = Net Migration
Example
Pop(t+1) = Pop(t) + B – D + MI - Mo
Russia
Pop(t) = 1,000
Births = 12/1,000
Deaths = 15/1,000
MI immigrants = 22/1,000
Mo emigrants = 20/1,000
Pop(t+1) = 1,000 + (12 – 15) + (22 – 20)
Pop(t+1) = 1,000 - 3 + 2 = 999
• Natural Increase = (12-15) = -3
• Net Migration = (22-20) = 2
FERTILITY & MORTALITY
Total Fertility Rate (TFR)= measures the # of births in a
society
World TFR = 2.6 TFR in Africa= 6 TFR in Europe=1.9
Infant mortality Rate (IMR)= Annual number of deaths for
infants under 1
MDCs= lower NIRs, CBR, IMR &TFR with higher Life
expectancy
LDCs= higher NIRs, CBR, IMR & TFR with lower life
expectancy
NIR
CBR
FERTILITY RATE
IMR
CDR- DOES NOT FOLLOW
THE SAME PATTERN
Some very wealthy countries have a higher CDR then some
of the poorest
Examples:
Denmark has a higher CDR than Cape Verde
The U.S has a higher CDR than nearly every country
in Latin America
How could this be?
BELL WORK 2/5
If a country has a high CDR & high CBR, what can we say
about this countries level of technology? Level of
development? Are they an MDC or LDC?
If a country has a low CDR & CBR what can we say about this
countries level of technology? Level of development? Are
they an MDC or LDC?
THE DEMOGRAPHIC TRANSITION MODEL
Stage 1
Stage 2
Stage 3
Stage 4
Low Growth
High Growth
Moderate Growth
Low Growth
Stage 5?
Declining?
Births/Deaths per 1,000
60
50
Sweden
Birth Rate
40
Mexico
Birth Rate
30
Death Rate
20
Death Rate
10
0
1750
1775 1800 1825 1850 1875 1900 1925 1950 1975 2000
Sources: B.R. Mitchell, European Historical Statistics 1750-1970 (1976): table B6; Council of Europe, Recent Demographic
Developments in Europe 2001 (2001): tables T3.1 and T4.1; CELADE, Boletin demografico 69 (2002): tables 4 and 7; Francisco
Alba-Hernandez, La poblacion de Mexico (1976): 14; and UN Population Division, World Population Prospects: The 2002 Revision
(2003): 326.
BELL WORK POPULATION PYRAMIDS-2/9
Dependency ratio-the number of people who are too young
or too old to work compared to the number of people old
enough to work.
Replacement Rate- the totally fertility rate (TFR) needed for a
population to replace itself. Varies by country, but for most of
the developed world it is 2.1
Doubling time The number of years needed to double a
population (exponential when it remains the same)
POPULATION AFFECTED BY
DEMOGRAPHIC TRANSITION
1. The % of the population in each age group
2. The distribution of males and females
POPULATION
DILEMMAS ACTIVITY
You and your group have been given one of 3 population dilemmas that
are currently affecting Europe. Follow the directions in the packet you
picked up at the beginning of class to complete this activity.
First! – You should brainstorm three answers to the question your group
is facing
Second! – you should read through your article and answer the second
question
Third!- finish the sentence at the bottom
Fourth!- Repeat steps 1 and 2 for the other side of your dilemma sheet
TAKE OUT THE SHEET FROM FRIDAY
What stage of the demographic
transition is each country facing?
What is one positive impact of the
population structure on its
economic development?
What is one negative impact of the
population structure on its
economic development?
Stage 2 - Expanding – high birth rate, low life expectancy
Positives- expanding workforce
- youthful population
- less need for immigrant labor
- less need for elder safety net
Negatives- high youth dependency ratio
- strain on resources
Stage 4 – Contracting – low birth rate, high life expectancy
Positives- educated workforce
- low youth dependency ratio
- may need immigrant labor which allows for citizens to take higher
paying jobs
Negatives- high elderly dependency ratio
- future labor shortages
- Greater need to fund social security
Stage 5 – Declining – small youth population, low birth rate
Positives- Need for immigrant labor means higher paying jobs for
citizens
- immigrants bring new ideas
Negatives- high elderly dependency ratio
- labor shortage
- inability to care for elderly
In 1798 he published An
Essay on the Principle of
Population
Malthus was the first to
sound the alarm that the
world’s population was
expanding more rapidly
than food production.
He was the first to
recognize exponential or
geometric population
growth.
Today those who share
his concerns are NeoMalthusians
Rev. Thomas Malthus
1766-1834
WORLD POPULATION GROWTH
Figure 2-8
WHERE HAS THE WORLD’S POPULATION
INCREASED?
Fertility
• Total fertility rate (TFR) – average number of children born to a woman over
her life
Mortality
-Infant mortality rate, child mortality rate, and
maternal mortality rate
-Life expectancy (greatly impacted by violence, infant
mortality, poor healthcare, epidemic disease, risk
factors)