S-curves and J-curves
- S-curves
- Start with exponential growth
- Above a certain population size, the growth rate slows down until population stabilizes
- Consistent with density dependent limiting factors
- Population size stabilizes at the carrying capacity (K) of the environment
- The area between the exponential growth curve and the S.curve is called environmental resistance
- J-curve
- Shows a boom and bust pattern
- Population grows exponentially then crashes
- These collapses/crashes are called diebacks
- Population often exceeds K before the collapse occurs which is referred to as overshoot
Growth Rates
- S and J curves are idealized
- In nature both types of limiting factors act on the same population and the result is an S/J combo curve
- The growth rate of the human population is slowing as we reach the K of our environment
- Peaked at 2.1% per year in 1965-1970
- Now: 1.3% and falling
- Back in the day world population was increasing slowly due to environmental resistance, diseases, epidemics, famine, and natural catastrophes
- MEDCs and LEDCs
- Countries are also economically classified based in the industrial development or GDP
- MEDCs
- are industrialized nations with high GDPs
- Relatively rich population and starvation is unlikely
- High Level of resource use per capita
- Relatively low population growth rate
- LEDCs
- are less industrialized or have none at all
- May have plenty of natural capital but usually this is exported and processed in MEDCs
- Lower GDP and high poverty rates
- Large population sector with low standard of living
- High population growth rates
