POPULATION DENSITY

Why do people choose to live in some places and not in others?
In the next tables you can find some reasons for explaning people's distribution.

PHYSICAL
	Densely populated	Examples	Sparsely populated	Examples
Relief	Flat plains and low-lying undulating areas	Bangladesh	High, rugged mountains	Andes
	Broad river valleys	Ganges Valley	Worn-down shield lands	Canadian Shield
	Foot hills of active volcanoes	Etna, Pinatubo
Climate	Evenly distributed rainfall with no temperatures extremes	North-west Europe	Limited annual rainfall	Sahara Desert
	Areas with: 1.high sunshine totals 2.heavy snowfall for tourism	1.Spanish coast	Low annual temperatures	Greenland
		2.-Swiss alpine valleys	High annual humidity	Amazon rainforest
	Seasonal monsoon rainfall.	Bangladesh	Unreliable seasonal rainfall	Sahel
Vegetation	Grassland (ease to clear/farm)	Paris Basin	Forest	Amazonia, Canadial Shield
Soil	Deep fertile silt left by rivers	Nile Valley and Delta	Thin soils in mountainous or glaciated areas.	Northern Scandinavia
	Volcanic soils	Etna	1.Laking humus 2.affected by leaching	1.Sahel 2.Rainforest
Natural resources	Mineral, e.g. coal, iron ore	Pennsylvania, Johannesburg	Lacking minerals	Ethiopia
	Energy supplies, e.g. HEP	Rhône  Valley	Lacking energy supplies	North-east Brazil
Water supply	Reliable supplies	North-west Europe	Unreliable supplies	Afganistan
Natural routes	Gaps through mountains, confluence of valleys.	Rhine Valley, Paris	Mountain barrier	Himalayas

HUMAN
	Densely populated	Examples	Sparsely populated	Examples
Economic	Ports	New York, Sydney	Limited facilities for ports	Bangladesh
	Good roads, railways, airports	Germany, California	Poor transport links	Himalayas
	Industrial areas (traditional)	Pittsburgh, Ruhr	Lack of tourist development	Sudan
	Development of tourism	Banff(Canada), Jamaica	Lack of tourist developments	Iraq
	Money available for new high-tech industries.	California, south of France	Lack of government investment	Nepal, Gaza
Political	Government investment	Tokyo region, north Italy	Lack of government investment	Dem. Rep. of Congo
	New towns	Satellite towns around Cairo, Brasilia	Depopulation of rural and old industrial areas	North-east Brazil, Belgian coalfield
	Reclamation of land	Hong Kong Island, Dutch polders	Loss of land, e.g. deforestation, and soil erosion	Amazonia, Apennines, Sahel
Social	Better housing opportunities	Arizona	Poor housing opportunities	Afghanistan, Soweto
	Education , health facilities, entertainment	Sydney, Milan	Limited education, health facilities, entertainment	Rwanda
	Retirement areas	Spanish costas, Canary Islands	Poor facilities for retirement	Eritrea

POPULATION EXAM'S CONTENTS

What you must study for the Population unit's exam:

• Historical development of the world's population (page 46 of your book)
• Current demographic trend (page 46)
• Demographic Transition Model. You can combine the contents on page 47 and the information posted in the blog.
• Natural movement of population: birth rate, death rate, infant mortality rate, general fertility rate, natural population rate.
• Population pyramids.
• Population density. Information I gave you in the class handouts and pages 48 and 49 of your book.
• Unite vocabulary.

HOW TO READ A POPULATION PYRAMID

CLICK HERE: This links takes you to a power point presentation that shows types of population pyramids and how to read them. That can help you to prepare the exam.

 CLICK HERE. population pyramid

POPULATION PYRAMIDS

A population pyramid is one way to look at the demographics of a country. 
Demographics are population characteristics, such as age, gender, race, religion, or language. A population pyramid looks at only age and gender. It is constructed to show how many people in a particular age group are male of female. This is done using a horizontal bar graph. The result is a clear picture of how a country's population breaks down according to gender and age, and where the most people occur according to those two piecws of information.

DEMOGRAPHIC TRANSITION MODEL

Population change depends mainly on the balance between the birth rate and the death rate. It is also affected by migration.

Throughout history the world’s population has usually shown a natural increase. Exceptions have occurred:

·         During times of disease (the bubonic plague in the Middle Ages and the HIV/AIDS (Human Immunodeficiency Virus, the virus that causes Acquired Immune Deficiency Syndrome) in present-day southern Africa.

·         As a result of war (western Europe during the two World Wars and in present day in Afghanistan)

·         Due to recent improvements in family planning and female education (either voluntary as in several western European countries or enforcement as with China’s one-child policy).

Demographic transition model

The demographic transition model shows the relationship between birth rates and death rates. It describes how, over a period of time, a sequence of change in population growth rates takes place. The model, which was based on population changes in several industrialised countries in Western Europe and North America, suggested that there were four stages through which all countries will eventually pass.

Stage 1. Here both birth rates and death rates fluctuates at a high level (about 35 per 1000) giving a small population growth.

Birth rates are high because:

• ·         No birth control or family planning
• ·         So many children die in infancy that parents tend to produce more in hope that several will live.
• ·         Many children are needed to work on the land.
• ·         Children are regarded as a sign of virility.
• ·         Religious belief (e.g. Roman Catholics, Muslims and Hindus) encourage large families.

High death rates, especially among children, are due to:

• ·         Disease and plague (bubonic, cholera, kwashiorkor).
• ·         Famine, uncertain food supplies, poor diet.
• ·         Poor hygiene: no piped, clean water and no sewage disposal.
• ·         Little medical science: few doctors, hospitals, drugs.

Stage 2. Birth rates remain high, but death rates fall rapidly to about 20 per 1000 people giving a rapid population growth.

The fall in death rate results from:

• ·         Improved medical care: vaccinations, hospitals, doctors, new drugs and scientific inventions.
• ·         Improved sanitation and water supply.
• ·         Improvements in food production (both quality and quantity)
• ·         Improved transport to move food, doctors, etc.
• ·         A decrease in child mortality.

Stage 3. Birth rates fall rapidly, to perhaps 20 per 1000 people, while death rates continue to fall slightly (15 per 1000 people) to give a slowly increasing population.

The fall in birth rate may be due to:

• ·         Family planning: contraceptives, sterilisation, abortion and government incentives.
• ·         A lower infant mortality rate, therefore less needs to have so many children.
• ·         Increase industrialization and mechanization meaning fewer labourers are needed.
• ·         Increased desire for material possessions (cars, holidays, bigger homes) and less for large families.
• ·         Emancipation of women, enabling them to follow their own careers rather than being solely child bearers.

Stage 4. Both birth rates and death rates remain low, fluctuating slightly to give a steady population.

Nowadays the MEDCs (the more economically developed countries) have reached stage 4 (UK, USA, and Spain). Meanwhile the more developed LEDCs have reached the 3 stage (India, Mexico, Brazil, and the least developed remain al 2 stage (Chad, Nigeria, Kenya).

It has been notice that since the 1990s several MEDCs appear to be entering in a new and fifth stage. This stage is where the birth rate is beginning to fall below the death rate. It is predicted that, if this trend continue, countries entering this stage will eventually see a natural decrease in their total population.

THE WORLD POPULATION GROWTH

In the previous unit you have learnt about relief, climate and natural landscape. You have also learnt how important nature is for people's survival.

In this unit you will learn about the world population and its evolution through History.

The following video shows how population has grown since the year 1C.E.  and what its evolution would be until the year 2050.

And if you click on the first image you  will see The USA and World Population Clock, which shows how the world's population is growing just now.

KEY WORDS AND TERMS
You must know the meaning of the following terms:

• birth rate
• death rate
• natural increase
• infant mortality rate
• life expectancy
• birth control
• dependent population
• dependency ratio
• family planning
• population piramids/age-gender structures
• replacement rate
• fertility rate
• ageing population.
• population distribution and population density
• a more economically developed country (MEDC)  and less economically developed country (LEDC)
• overpopulation and under population.