Demography PP

Document Sample
Demography PP Powered By Docstoc
					Demography




       It’s All About People!
Demography is the study of populations. It helps answer
questions such as:

 Why are more schools closing than opening?
 Why will you likely have to work more years than your
  parents before retiring?
 Why are old rock-and-roll groups, such as the Rolling
  Stones, still so popular?
…?
How do we compare countries that have populations of
                 different sizes?




          We use RATES, not NUMBERS!
Look at the number of births for these
three countries:




 Canada: 330,000 babies born in 2003
 Russia: 1,458,000 babies born in 2003
 Togo: 191,000 babies born in 2003
  To calculate each country’s birth rate,
divide the number of births in one year by
the population, and multiply the result by
                  1000.
      Math!




           births
                    1000   birthrate
         population
So...birth rate...




• Canada (330 000 / 32 207 000)  1000 = 10
• Russia (1 458 000 / 144 526 000)  1000 = 10
• Togo (191 000 / 5 429 000)  1000 = 35
In a similar fashion, rates can be calculated for:

     •number of deaths
     •number of immigrants
     •number of emigrants                 MORE
                                          Math?
  deaths
           1000  deathrate
population

immigrants
           1000  immigrationrate
population
Rates can also be combined in the following
manner:

 • natural increase rate = birth rate –
   death rate
 • net migration rate = immigration rate –       Oh
   emigration rate                              come
                                                 on!


 births             deaths           
           1000            1000 
population         population        
Population Growth Rate




   A country’s population growth rate
      = natural increase rate + net
Canada’s Population Growth Rate
           What’s your thesis?

  The thesis is the big idea; it’s the key to any
          persuasive piece of writing.

        It's the point you want to prove.

        It's the focus of the whole thing.

Everything you do in the piece should grow from
    your thesis--that's how important it is.
             So, here’s the statement:

  The rate at which a country’s population grows or
declines has an enormous influence on people’s lives.




 Come up with a thesis statement that agrees or
        disagrees with the statement.
      Comparing Population Growth Rates

These population growth rates may not seem
very different:

 • Canada - 0.8%
 • Russia – 0.4%
 • Togo - 2.4%

But we need to consider the impact of
“compounding.”
                  The Power of Compounding
To help pay for your future education costs, your parents
offer you two choices. For 30 days, you can receive one
of the following:




»Fig. A $1000 + $1000 + $1000 + $1000 …   »Fig. B 1 cent + 2 cents + 4 cents + 8 cents …




Which one would you chose: Fig. A or Fig. B?
If you selected Fig. B, you would have a lot more money
for your education. Why? Because growth occurs on top
       of the growth that has already taken place.




     »Fig. A $30 000             »Fig. B $10 737 418.23
Here is the impact of compounding on the populations of
   Canada, Russia, and Togo for the next 100 years.
                 Doubling Time
Doubling time is the time it takes a
population to double at its current growth
rate.
                                             That’s it,
• You could calculate doubling time with       I’m
  fancy mathematics…                         leaving!
                                                …




• Or, you could estimate the time by…
…using the Rule of 70, which
states that doubling time
 is equal to 70 divided by the
population growth rate.

Canada’s population growth      Fine. I’ll
 rate is 0.8%.                     stay!


Therefore, Canada’s doubling
 time is approximately 87
 years (70/0.8).
• Canada’s doubling time is 87 years.
• Togo’s doubling time is 30 years (70/2.4).



Which country can more easily deal with its population
                     growth?




                          VS.
Population Pyramids


 It is easier and faster to
  understand population
 structure if the data are
          graphed.

    Two bar graphs are
       constructed.

The first one looks like this.
The second bar
graph looks like
     this.
Combine the two sets of bar graphs to create a
population pyramid that shows the age/gender
    breakdown of a country’s population.
                 Dependency Load
 The dependency load is the part of the population that
needs to be supported. It is made up of two components:
     the 0–14 age groups and the 65+ age groups.
What has happened to the dependency load between
                 1956 and 2004?
      What is the significance of this change?
       Stages of Population Change

Populations within countries change over time in a
               predictable manner.

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:4
posted:4/6/2012
language:English
pages:26