1
Loosens up soil for planting.
Plowing.
Filtration and chlorination of water to remove microorganisms and toxins.
Water treatment.
The total value of goods and services produced per year, per person.
GDP per capita.
Birth rates and death rates are both high, keeping the population stable.
Preindustrial.
Stable or slow growth.
Stage 1.
The selection of human-desired traits in domesticated species.
Estimates how long it will take a population to double in size at its current growth rate.
Doubling time.
When people move into an area, increasing the population.
Immigration.
Death rates fall rapidly as access to food and medicine improves.
Early transition.
Life expectancy increases. Rapid growth.
Stage 2.
Many diseases are caused by microorganisms.
Germ Theory.
Measures how long an average newborn will live.
Life expectancy.
When people leave an area, decreasing the population.
Birth rates gradually fall through a series of social changes.
Late transition.
Decreasing birth rates. Stable.
Stage 3.
Injections of dead and weakened viruses to prevent disease.
Vaccines.
Less than 1 year old.
Infant mortality rate.
High birth rate (>2.1) offset by low life expectancy.
Initial Stability.
Birth rates reach equilibrium death rates and the population stabilizes.
Industrial.
Further decreasing birth rate. Negative growth.
Stage 4.
Chemicals that selectively kill bacteria.
Antibiotics.
The average number of children a woman will have in her lifetime.
Total fertility rate.
High birth rate (>2.1) plus increasing life expectancy.
Rapid Growth.
Birth rates continue falling due to a series of antinatalist forces.
Post-industrial.
Roughly 6 million more boys than girls in each age group since 1980.
Son Preference