martes, 5 de octubre de 2010

Population size impact and changes

Impact
Population size is not the only factor that determines our species impact on the environment.
  • Resource use and pollution
  • Amount of wealth
  • Resource desire
  • Resource need
Many environmental impact models are based on the assumption that all individuals in a population have the same resource use and waste profile and thus impact the environment equally.


Changes
4 main factors for population changes:
  • Birth rate
  • Death rate
  • Inmigration
  • Emigration
The measures of population change are:
  • Crude birth rate or CBR = (Number of births)/(Total population) * 1000
  • Crude death rate or CDR = (Number of births)/(Total population) * 1000
  • Natural increase rate or NIR = (CBR-CDR)/10
  • Doubling rate = 70/NIR
  • Total fertility rate: The number of children every woman is having in a determined area. The total fertility rate in the world is 3, 1.7 in MEDCs and between 3 and 6 in LEDCs
  • Also important to note: Population density = (Total population)/(Total area)

No hay comentarios:

Publicar un comentario