Population Pyramids and the Demographic Transition

Sections 02 & 03 had good discussions today (thank you!) as we started looking at Population Pyramids.  An incredible site for seeing how the pyramids can change over time can be found here, and a nice summary of these pyramids can be found here.

Section 01 moved on to a discussion of the famous Demographic Transition.  Here's a recap of the four stages, plus the chart we covered today (with a bonus: Stage Five!):

Four stages of Demographic Transition

a. Stage 1:  High birth rate, high death rate; very slow growth, low RNI. In pre-industrial society, death rates and birth rates were both high and fluctuated rapidly according to natural events, such as drought and disease, to produce a relatively constant and young population. Children contributed to the economy of the household from an early age by carrying water, firewood, and messages, caring for younger siblings, sweeping, washing dishes, preparing food, and doing some work in the fields.

b. Stage 2:  Death rate falls dramatically, birth rate remains high; high RNI. A consequence of the decline in CDR in Stage Two is an increasingly rapid rise in population growth, called the "population explosion"), as the gap between deaths and births grows wider.

c. Stage 3:  Death rate remains low, birth rate drops; RNI slows. Stage Three moves the population towards stability through a decline in the birth rate.

d. Stage 4:  Death rate low, birth rate low; low RNI (as in stage 1). This occurs where birth and death rates are both low. Therefore, the total population is high and stable.

*Highest RNI is in stage 2*