BY DR: MUHAMMED NAJEEBAssist: Professor

Community Medicine Deptt: LUMHSJamshoro Sind, PAKISTANE mail mnajeeb80@gmail.com

DEMOGRAPHY

POPULATION PYRAMIDS

Pictorial presentation of 3 Factors (Influence Population)Births

DeathsMigration

Features (Population Pyramids)

In terms of its composition by:- Age, Sex Males (on Left side) Females (on Right side) Children (at bottom) Elders (at Top) Adjoining bars (contribution of each age, Sex group)

Developing Country (Pakistan)

Base: Broad (High Birth rate)Top: Narrow / Acute apex (No: of Elders (Less)

High Dependency rate Bad effect (on Economy) Unproductive (Half Pop) Under 15 Ys: ---- 44% Pop: B/w 15- 64 Ys: 52% Pop:

Developed Countries (Sweden)

Base: Narrow (Low Birth rate)Middle: Bulge (Convex border)Top: Obtuse apex (More Elders)

Low Dependency rate Good effect (on Economy) Productive ( More than Half Pop) Under 15 Ys: ---- 25% Pop: Above 15 Ys: ---- 75% Pop:

EXAMPLE

PAKISTAN SWEDEN

WORLD POPULATION

PAKISTAN

http://www.google.com.pk/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=SjveybEg3MP4EM&tbnid=MUkbV6UFCFKGSM:&ved=0CAUQjRw&url=http://wpolitika.wordpress.com/category/european-politics/&ei=d6AOUYjWJI3MtAbNzYHIBw&psig=AFQjCNHluc37UCsG-fw-lmRi6isyJgKcww&ust=1359999239478904

DEMOGRAPHIC CHARACTERISTICS

Population unevenly distributed with

All countries in region have a positive rate of natural population change.

very densely populated areas

very sparsely populated areas.

1.

DEMOGRAPHIC TRANSITION

Growth Rate (%) Grading of population increase

0 ( Zero)

0 to 0.5

0.5 to 1

1 to 1.5

1.5 to 2.0

> 2

Stationary Growth (No Growth)

Slow Growth

Moderate Growth

Rapid Growth

Very Rapid Growth

Explosive Growth ( Population explosion) OR Population Bomb

Two demographic worldsLess-developed counties represent 80% of the world population, but more than 90% of projected growthRicher countries tend to have negative growth rates.

DEMOGRAPHIC TRANSITION 3 TYPES

1. Old balance Fertility Mortality

2. New balance Fertility Mortality

3. ImbalanceFertility Mortality

India in 1920-1930

Many countries of S. Asia & Africa

China,SingapurPak in 1970

Germany,Hungary (after effect of II world war)

DEMOGRAPHIC CYCLE

PopulationGrows slowly

PopulationGrows rapidly

PopulationBecomes stationaryPopulation

stationary

Populationdeclines

15

Demographic Transition AccompanyingEconomic and Social Development

BBirth Rate

Death Rate

Note that in English, fertility refers to actual births.

Fecundity refers to the biological ability to have children (the opposite of sterility).

Dependency Ratio

The dependency ratio tells us how many young people (under 16) and older people (over 64) depend on people of working age (16 to 64). The dependency ratio is worked out with this formula.

Dependency Ratio = % under 15 + % over 65 ys: X 100 % between 15 & 64

A worked example should make this clearer. Pakistan, which is a developing country, has 41% of its population less than 15, and 4% over 65. This makes 55% (100 - (41+4)) between the ages of 15 and 64.

Dependency Ratio = 41 + 4 X 100 = 81.8 55

END