sábado, 15 de diciembre de 2012

Eropean Union

World population distribution


Population density

Population density is the relation between the number of inhabitants of a place and the surface that this place occupies.  

In general it is considered that an area is little populated when it has a density of 10 inha./km2. And it is a very populated 

area, if the density exceeds 80 inha./km2.

Model of population cycle



The model of demographic transition progresses in four stages:

-Old or preindustrial demographic regime: it is characterized by high mortality and natality rates. Sometines Mortality rate is higher than natality rate, therefore there is a negative natural increase.

-First transition: keep the high natality rate, but mortality decrease, because of andvances in sanitation and health care.

-Second transition: the natality rate begins to decline, but mortality is still down, so there is balance.

-Modern demographic regime: mortality and natality are very low and sometimes natality rate falls so much that there is a negative natural increase.
The model of demographic transition progresses in four stages:


Map of natural increase of world population