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Module 22: Human Populations

Every day:

  • 2.1 million infants are born (2,100,000)
  • 800,000 people die
  • result: global population increases by 1.3 million (2.1-0.8 = 1.3)
  • this assumes no aliens landing, nobody going to Mars (yet)
We describe this as a population growth rate in percent this way:
Growth rate % = (crude birth rate - crude death rate)/10

Real numbers:
CBR = 20%
CDR = 8%
20-8 = 12, so growth rate is 1.2%. (12/10)

Long ago, before clean water, health care and agriculture, CBR and CBR were about equal, so very low growth rate
Malthus: Top graph

Screen Shot 2022-10-23 at 5.54.07 AM.png
Screen Shot 2022-10-23 at 5.54.07 AM.png

A similar thing happened in the 1960's in Mexico, when population was increasing much faster than food supply, until Norman Borlaug created dwarf wheat, by creating a hybrid between heavy kernels and short stalks.

Population growth as a system: Inputs and outputs:
Screen Shot 2022-10-23 at 5.56.53 AM.png
Screen Shot 2022-10-23 at 5.56.53 AM.png


Nations are a bit different: people can immigrate (come in) and emigrate (leave for somewhere else)
n.b. the global population stays the same, they are just moving around the planet

National model:
((CBR + Immigration) - (CDR + emigration))
                                10
Try this:
Doofania has a CBR of 12%, CDR of 4% with an immigration rate of 2% and emigration rate of 3%
What is the % growth rate for Doofania?

There is a very easy way to use this to calculate number of years for a population of ANYTHING to double:
70/% = number of years to double ("doubling time")
So, Doofania would take 70/7 or 10 years to double.
Watch:
70/3.5 = 20 years
70/14 = 5 years
On the AP exam, all questions will use a multiple or fraction of 7 (35, 3.5, 7, 14, 28, etc.)

Fertility: (also known as "fecundity")
TFR is the total fertility rate, the average number of children each women will have.
n.b. TFR is not based on 1000 people like CBR and CDR, but is about EACH woman
TFR in the US was 1.8 a few years ago. This changed with COVID (why?)

Replacement level fertility: TFR needed to keep the population stable in a country
Where lifespan is short, TFR must be higher (war, famine, poor water, no food, no healthcare)
One reason families hundreds of years ago had many children (many did not survive to adulthood)
Present numbers are about 1.2 for TFR (some children don't survive, or have children themselves)

Screen Shot 2022-10-23 at 6.13.15 AM.png
Screen Shot 2022-10-23 at 6.13.15 AM.png

LDC (lesser developed countries)
Look at the average lifespan distribution-what do you see?

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Men have shorter lifespans: war, work, testosterone, heart disease, smoking, cancer
Look up the life expectancy of men and women your parents' age
Compare with someone born in 1900
How many were farmers then?

Now compare the life expectancy image with this one: (infant deaths before age 1, child deaths under age 5)
One reason the one year birthday is such a big deal here in Hawaii

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Why?
  • clean water
  • health care
  • food supply
  • sanitation
  • lower pollution
Global IMR: 32
US: 5.8
Sweden: 2.5
Why?
Not just about countries...
US: 5.8 
African American: 12
Native Americans: 7.6
Caucasians: 5.3
Closer to home:
Hawaii: 4.9
Native Hawaiians, Pacific Islanders: 9.4
Why?
Social, education, income, food supply, food deserts, diet

Crude death rate also depends on demographics:
Mexico: 6% over 65, CDR is 5/1000
US: 15% over 65, CDR is 8/1000

National Net migration rate: people in - people out
US: 1 million in, very few out, so 1/325 = .003 or 3/1000
US: TFR of 1.8 (below replacement level of 2.1) 
but: many immigrants, so population is still growing

Screen Shot 2022-10-23 at 7.14.58 AM.png
Screen Shot 2022-10-23 at 7.14.58 AM.png

Age Structure Diagrams: (so cool!)
Screen Shot 2022-10-23 at 7.15.49 AM.png
Screen Shot 2022-10-23 at 7.15.49 AM.png

How to read these:
  • men on left, women on right
  • kids at bottom, old people at top
  • bulges are greatest populations
  • look for:
    • wars (on whose soil?)
    • famine
    • immigrant workers
    • pyramids
Question: What does a neutral growth country look like?

Age structure diagrams/population pyramids-check these out: 
UAE, Japan, Sudan, Iraq/Iran, Russia----WHY?
See also baby boom and boom echoes...Check this out: https://www.populationpyramid.net/world/2022/
...and look these up:
  1. Go to 1950 and look at the US population. Look again in 1960. Where is the baby boom? Why were there so few babies born during 1940-45?
  2. If you were a 42 year old American in 2000, when were you born? How old are your kids? Find the "boom echo".
  3. Find the impact of the Iran/Iraq war of 1980-89, which side had the biggest impact? If you were a 35 year old Iraqi man in 1995, how old were you during this war?
  4. If you are a 30 year old German man in 1950, when were you born? How old were you in WWII (1936-1945)? 
  5. If you were a 35 year old woman in Japan in 1960, why are there so few men to choose from?
  6. Look at the UK in 1960. Where are the casualties of WWII, and are they both male and female? Explain.
  7. What the heck is going on in UAE?
  8. Look at Russia in 1960. What gaps do you see? Why?
  9. Information about China is very spotty-why would this be? See if you can find the impact of the one-child policy from 1979-2021.
  10. Compare present day Japan to Africa. What issues will they need to address?
  11. Look at present day Italy, Japan and Germany. What is common?
  12. Compare present day India and China. What do you see?

Terms to know: Human Populations-----------------------------

Fecundity: the ability to reproduce

Fertility: production of offspring

CBR: crude birth rate: births per 1000 people

TFR: total fertility rate: total kids per woman in her lifetime (25-30!)

ZPG: zero population growth: 5+ where infant mortality is high, 2.1 is normal

China: was 6 -> 1.8 (below replacement level since 1979, one child policy)

China has a 140/100 male to female ratio: why?

Global TFR is 2.6

CDR: crude death rate: deaths per 1000

Why is there a life span? mitochondrial DNA...

1900 Indian man had life expectancy of 23! Trace this to now...

Not now, reasons: nutrition CLEAN WATER, sanitation, education

75 men, 85 women (testosterone, war, "hold my beer and watch this!", Darwin Awards)

Dependency ratio; baby boomers and your future: how many workers to retirees

imagine your life at your age in other countries...

Russia low TFR: alcoholism and antibiotic resistant Tuberculosis




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