Demographic Transition Model

1. Resource limitation models are unrealistic for human population growth

review "Logisitic model"

r and K parameters

resource depletion models

resource --> population

 

2. Human population model

birth and death rates explicitly (not net growth rate)

 

"systems model" of this

factors that control these

resource level

social and technological infrastructure

human choices for their own future

 

3. Demographic transition model

describes how people in industrial societies decided to have fewer children

important question - does this model help predict what will happen

four stages of the demo trans

1. preindustrial

2. infrastructure improvements - mortality transition

3. humans choose to have smaller families - fertility transition

4. post-industrial

sketch the net growth rate and population size

4. Many of the factors that contribute to this decision are economic

when people have more economic stability, they reduce their family size

linking human growth rate to economic growth rate

if population grows faster than economy then per captia wealth decreases

if economy grows faster than population then per capita wealth increases

wealth per capita seems to be a major factor in fertililty decisions

suggested reasons for the fertiility transition

• availability of family planning (birth control)
• delay first birth until later years
• women gain access to education
• women gain access to jobs and economic
• women gain political rights and higher social status
• government incentives for having smaller families (or penalties for larger families)
• decreased utility of having many children in a agricultural economy
• increased value placed on supporting and educating children so that they can work in the industrial economy

correlations are not necessarily causes

 

5. Humans choose to control their population

individuals make decisions for their own personal good

combination of factors make that a good social transition

i.e. they don't consciously try to force the demo trans

 

 

6. Poverty "traps"

general definition of an environmental trap

by the time you get into it, you have a hard time getting out

a "trap" is not a "dead end", you don't just turn around

often traps

slow processes build up

behaviors/mechanism that got you in won't get you out

require a shift (technology, behavior, culture)