Population Dynamics and Migration

8/9/2019 Population Dynamics and Migration

http://slidepdf.com/reader/full/population-dynamics-and-migration 1/33

Population Dynamics and Migration



What is a Census?

A census is a count of the population of a

country. A census also f inds out f acts about thepopulation, such as their age, sex, jobs they do,

type of house and what language they speak. It

is usually carried out every 10 years.

Why do you think it¶s important to take a census?



What is a Census?

A country will carry out a census because:

The government needs to know how many

people live in each part of their country; it then

knows where to spend its money

They also f ind out about population trends; this

allows them to plan ahead

They can f ind out about the population structure -

how many old, middle aged and young people there

are; this again allows the government to target their

spending - on, for example, retirement homes or

schools



Census Difficulties

Some countries have a lot of diff iculty carrying out

censuses and some countries don't have censuses

at all. The reasons for this are

They cost a l

otof

money which p

oor c

ountriescan't afford

Some people live in diff icult to reach areas

Wars make counting diff icult

Nomads also make counting diff icultPeople who are illiterate are unable to f ill out the

forms

Some people do not tell the truth for political or

religious reasons



Vital Registrations

This is a method of counting the population by

caref ully using the records of births, marriages,

adoptions, divorces and deaths. This method is

cheaper, but it does not give as much informationas a census. It does, however, give a continuous

record, whereas a census gives a "snap-shot"

picture every 10 years.

Another way is by a sample survey where af raction of the population are surveyed. This

method has the advantage of being cheaper than

a census, but the disadvantage of being less

accurate.



How Is the Population Distributed?

People do not live evenly spread thr ough the

world. Large parts of the world are very sparsely

populated (low population density), whereasothers are cr owded (high population density). The

spread of people ar ound a country is known as its

population distr ibution

Areas with high population include WesternEur ope, the Eastern states of the United States,

India, Japan and China.




The f actors that tend to pr oduce low population

density (negative f actors) are

Extreme climate - too cold, hot, wet or dry Extreme relief - too high and too steep

Extreme remoteness - places that are diff icult

to reach

Inf ertile land - need to have extensive (verylarge) f arms

Backwards economy, with low pr oductivity

economic activities




The f actors that can pr oduce a high population

density (positive f actors) are

Moderate climate

Fertile f arming land Mineral resources - mines pr oduce jobs, and

pr ovide raw materials for other industries

Low land - with gentle slopes or f lat gr ound

Good water supply

Wealthier areas - people will move to where the

jobs and money are found

A long history of land occupation




Choroplethmap showing population distribution




Cartogram showing population distribution by countries






Now let¶s play...



Causes of Population Growth

Population growth is the balance among birth-rate,

mortality rate and migration:

If there are more births than deaths in a year therewill be what is called a natural increase of

population. In the opposite case, there will be a

natural decrease.

To give account of the whole population of an area(country, region, etc.), migrations must be

considered as a complementary factor to natural

growth.




In order to compare the different rates of population

growth two indicators are used:

Birth rate: the number of babies born alive per thousand of people per year.

Br=Births/Population·1000

Death rate: the number of deaths per thousand of

the population per year.

Dr=Deaths/Population·1000

Migration: the number of people moving in or out.




Differences in birth rates may be classified as:

Socio-economic: age of marriage, work of

women, wealth level, age-sex structure, poverty

levels, infant mortality rate...

Cultural: female literacy levels, religious beliefs

Political factors: policies adopted by governments

in order to encourage or discourage births,

conflict...




Differences in death rates are essentially socio-

economic:

Age of population Nutrition levels

Access to fresh water

Hygiene levels

Amount and quality of health services available Levels of conflict and violent crime

Actividad

Population

explosion

worksheet



Demographic Transition Model

Fotocopiar gr áf ico



Fotocopiar gr áf ico

The structure by age of any population has important

economic consequences. One of them is derived from

the Dependency Ratio, defined as the proportion between the working (people between 16 and 64 years

old) and the non-working (people between 0 and 16

years old and over 65 years old) parts of a given

population.It is worked out with the following formula: D.R.=

(people under 16) + (people over 65) / (people between

16 ± 65).

What Is a Dependency Ratio?




Spain (2010)

0-14: 5,888,000; 15-64: 27,213,000 ; 65+: 7,447,000

DR = (5,888,000 + 7,447,000 / 27,213,000) = 0,49

Angola (2010)

0-14: 5,670,000; 15-64: 7,044,000; 65+: 353,000

DR = (5,670,000 + 353.000 / 7,044,000); Td = 0.85

In the case of Spain, for each person in working age there

is 0,49 dependent people; in the case of Angola, 0,85.

This sometimes is transformed into a percentage

multiplying by 100.




The results have a bearing on the education, health and

social security policies of governments.

Countries that have a high dependency ratio have more people who are not of working age, and fewer who are

working and paying taxes. The higher the number, the

more people that need looking after, which results in

increased expenses in health, education or retirement pensions



Population Pyramids



Population pyramids are used to show information aboutthe age and gender of people in a specific country.

Male Female

Population in millions

In thiscountry

there is ahigh Birth

Rate

There isalso a high

DeathRate.

This population pyramid is typical ofcountries in poorer parts of the world

(LEDCs.)



In some LEDCs the

government isencouraging couples tohave smaller families.This means the birth

rate has fallen.



Male Female


In thiscountry the

number ofpeople in eachage group isabout the

same.

The largestcategory ofpeople wereborn about

40 yearsago.

In this country there is a low Birth Rateand a low Death Rate.

This population pyramid is typical ofcountries in the richer parts of the world

(MEDCs.)




Male Female

In this

country thebirth rate isdecreasing.

In the future the

elderly people will makeup the largest sectionof the population in this

country.

This is happeningmore and more in

many of the world·sricher countries.



Male

Female

Population in thousands

This country has a largenumber of temporary

workers. These are peoplewho migrate here especially

to find a job.



What is going to happen to

Japan·s population in thefuture?

Why does this matter?



Is Indian population expanding

now?

What makes you think so?

What is going to happen withIndian population in the future?



Your task:

Open your own PowerPoint presentation.

Go to www.census.gov www.census.govSelect Search and type in IDB.

Select International Database

From here select Population Pyramids.

Find a population pyramid typical of a poor country (LEDC) copy andpaste it into your PowerPoint document then add labels to explain whatis shown.

Repeat for an MEDC (rich) country.

For a country of your choice copy and paste the pyramids for 2000,2025 and 2050.

Write about what the graphs show and try to give reasons for thepatterns. Explain how the population of this country is changing and sayhow that could affect the country.



W

hen you have finished;Find out some background information on eachcountry and add this to your presentation.

Concentrate on facts and figures which you can

use to compare the countries such as % of thechildren at school, type of jobs available, how richor poor (GDP per capita.)«««



Migrations

Migration is the movement of people f r om one

place to another, implying a change of residence

or address.

Actividad

Population

explosion

worksheet



Migrations

Migrations can be classified in several ways:

Depending on the destination, they can be

national, international or even intercontinental.

Depending on the motives they can be economic, political or religious. In the latter cases we talk

about refugees, not emigrants.

Depending on the duration, they can be temporary

or definitive. Depending on the will of the migrants, they can be

voluntary or forced.

Give an example of each type of migration



Migrations

From the previous framework some specific examplesof migrations must be singled out:

International migrations from LEDCs to MEDCs, due

to economic causes.

Rural-urban migrations, common in LEDCs Brain Drain migrations of highly qualified people.

Counter -urbanisation in MEDCs, from cities to rural

areas, which increases the number of commuters.

Refugees, forced to leave their country due to hardship

or political oppression

Make a guess about the pushing and pulling factors behind

each example

Documents

Population Dynamics and Migration