04-25-2017, 07:22 PM
85_Ranger4x4 Wrote:So if life span was halved it wouldn't effect the population either?
Lifespan will not effect population size over the long term. Population growth over the long term is determined only by the ratio of births(and immigration if dealing with a nation/geographic area) to deaths (and emigration).
Total Pop: 100
Death rate per year:2
Birth rate per year: 2
life span: 50yr
Population after 1 year: 100
Population after 2 years: 100
Total Pop: 100
Death rate per year:2
Birth rate per year: 0
life span: 50yr
Population after 1 year: 98
Population after 2 years:96
Total Pop: 100
Death rate per year:2
Birth rate per year: 2
life span: 70yr
Population after 1 year: 100
Population after 2 years: 100
Total Pop: 100
Death rate per year:2
Birth rate per year: 0
life span: 70yr
Population after 1 year: 98
Population after 2 years:96
With a birth rate of zero there can never be population growth (if you have 7 rifles and never buy/make/acquire more, 7 is the most you will ever have, no matter how long they last), only a possible slowing of population decrease (due to the decrease of deaths attached to the increase in lifespan) for the number of years that the life span increased. In this case 20 years. Death rate will never be zero, so with a zero birth rate the population will always decline. After this period of time, it will level out and lifespan will again be irrelevant.
I believe the point of the paragraph was that a decrease in birth rate combined with an increase in lifespan is leading to an aging population requiring more care and automation. This also means fewer people of fighting age.