Current anthropological data strongly suggests that the first Homo sapiens arrived on the scene in Africa about 135,000 years ago.

For thousands upon thousands of years early Homo sapiens must have constantly struggled to maintain their species somewhat precarious grip on existence.

Demography is the study of the size, composition, distribution and growth or decline in human populations. Demography is generally considered a discipline within the field of sociology.

Demographers utilize information and data from many areas including but not limited to, agriculture, biology, economics, geography, NASA, political science, and statistics.


Thomas Mathus published An Essay on the Principle of Population in 1798.

Mathus's general idea is simple, "...the power of population is indefinitely greater than the power in the earth to produce subsistence for man." Mathus felt that human population growth always tended to be faster than the growth of the food supply.

Positive checks function to control the population by eliminating existing people by raising the death rate.

1. Hunger (Death by Starvation)

2. War.

3. Disease

Preventative checks funtion to control the population by preveting growth by slowing or lowering the birth rate.

1. Deferred Marriage

2Cibacy (Abstaining from Sexual intercourse)

Doubling time is an expression of the number of years in which a given popualtionwould take to double itself.

Human beings (as all living organisms) are biologically driven to reproduce. (Those individuals with the strongest sex drives, all thing being equal, are the most likely to produce offspring.)

Most human cultures place a positive value on reproduction. Western Christian ezample: Genesis Chapter 9vs. 1 & 2. "And God went on to bless Noah and his sons, and said unto them, 'Be frutiful, and multiply, and fill the earth'."

Sex Ratio is the number of males in a population per each 100 females. The sex ratio is stated as one number of males/per 100 females.

The Crude Birth Rate is an expression of the number of births per 1,000 persons in a given year.

Births in A year X 1,000 = Crude Birth Rate

Mid-year population

The Crude Death Rate is an expression of the number of deaths per 1,000 persons in a given year.

Deaths in A Year X 1,000 = Crude Death Rate.

Mid-year population

The Fertility Ratio is an expression of how many small children a population has in relation to the number of women of child-bearing age.

Child Bearing Age = 15-44 or 30 years

Small Children = All children born in the last 5 years.

No. of Children under 5  X 1,000 = Fertility Ratio.

No. of Women 15-44

A Fertility Ratio of 1,000 would mean that the average woman would have one child every 5 years and that the average woman would have 6 children during her child-bearing life.

The theory of demographic transition is an explanation designed to show the relationship between a nation undergoing industrialization and the birth rates and death rates of the nation.

Stage of Industrialization ------Death Rate------ Birth Rate------Population


Early Industrial------------------Low--------------High----------Explosion

Mature Industrial----------------Low--------------Low----------Stable

Some Web sites to visit:

Habitat for Humanity Home(page)s Around the World

Penn State Population Research Institute

US Demography

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