Module 22: Human population models
Migration
Welcome inback!
Today:
- review
progresssemester exam #2: 9, 27, 42, 64, 73, 79 - note taking: how, why, best practices
- sem 2 overview: human pop, energy, health, green building
- read chapter 6, cengage text (human populations)
- read module 22, FR3e (HW)
- prep for country choice
- Videos: Bozeman science: 012, 013, 014, 015
- http://www.bozemanscience.com/ap-environmental-science
- Homework: Bozeman 012, 013 (take notes), mod 22
- module 22 is part of chapter 7: https://elab.hpa.edu/apes/texts/parts/fr3e-chapter7.pdf
- Carrying capacity for the earth: about 9 billion
- Malthus: exponential growth of population, linear growth of food supply (ignores innovation):
Population inputs:
- Immigration
- Births
- Aliens landing on earth
Population outputs:
- Emigration
- Deaths
- People moving to Mars
Two crude concepts:
- CBR: crude birth rate: births per 1000 people per year
- CDR: crude death rate: deaths per 1000 people per year
- Global population change: (CBR-CDR/10) notice that 1000/10 = 100 so it looks like a percent
For a country:
National population % growth rate =
[(CBR +immigration)- (CDR+ emigration)]/10
- In words this says all things coming in, minus all things going out, divided by ten is the national growth rate in percent (per hundred)
- Births are easy to calculate (except in rural areas where some live, some don't and are rarely reported)
- Life expectancy: average number of years a newborn is expected to live
- Global: 73 years (70 men, 75 women)
- US: 79 years (76 men, 81 women)
- Look up your life expectancy and that of your parents
Infant mortality: number of deaths for children under 1 year per 1000
Child mortality: number of deaths for children under 5 years per 1000
Math stuff: sure to be on the AP exam...
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?
If the replacement ratio for stable population is 2.1 kids per woman (why?) is a parallel age structure diagram stable or declining?
This is also known as "replacement level fertility"
Total fertility rate: TFR: total number of children each woman will have in her lifetime between 15 and 49 (does not count men, divorce, death of spouse)
Time to visit gapminder.org: https://www.gapminder.org/tools/?from=world#$chart-type=bubbles&url=v1
Millenium UN goals:
Men have shorter lifespans: war, work, testosterone, heart disease, smoking, cancer, "hold my beer and watch this"
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
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
Why?
- clean water
- health care
- food supply
- sanitation
- lower pollution
Global IMR (infant mortality rate): 32
US: 5.8
Sweden: 2.5
Why?
Sweden: 2.5
Why?
Not just about countries...
US: 5.8 average
- African American: 12
- Native Americans: 7.6
- Caucasians: 5.3
- Closer to home:
- Hawaii: 4.9
- Native Hawaiians, Pacific Islanders: 9.4
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
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
Study these and pick one to study:
Recall exponential growth:
- At = Aoe^rt where r is the reproductive rate in % and Ao is the original population
- We need to know how fast a population is growing better than just % growth rate
Here's how:
Here's why:
- When the population doubles, the ratio of At/Ao is 2
- If At/Ao = 2 = e^rt then ln 2 = rt = 0.693 (mysterious thing: look up the ln of 1/2 and 2, see?)
- so, 0.693 = rt, then t = 0.693/r
- since r is in percent, then 70/(growth rate in %) = time to double the population
On the AP exam, you will see questions using some multiple of 7: 14%, 35%, 3.5%, 28% to calculate population doubling time: Make sure you understand that higher % means SHORTER doubling time...
Population check in:
Population check in:
- An r-selected species has a growth rate of 12%. If the initial population is 200, what will be the population at year 5? (hint: use the Nt = Noe^rt formula)
- What is the doubling time for this population? (hint: use 70/% to get doubling time)
- If the carrying capacity of a separate K selected species is 100, what will the slope of the growth curve look like when the population is 95?
- What will it look like when the population is 120, and what do you call this?
Sample AP FR question:
Solution:
Videos:
Bozeman science: 013, 014, 015
Bozeman science: 013, 014, 015
Millenium UN goals: Hans Rosling TED talk:
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