Population dynamics

Seite 1

The population of the world is growing at an exponential rate. The two things that affect the population size is the birth rate and the death rate.

Seite 2

World Population

The world population is growing at an exponential rate. The two things that affect the population size are the birth rate and the death rate. This is because the birth rate is greater than the death rate and life expectancy is increasing. Life expectancy is increasing because of better medical and health care, improved hygiene and increased food supply due to advances in technology

Seite 3

Population growth and structure

The demographic transition model and population shapes.

Seite 4

In stage 1...

The birth rate is high and fluctuating

The death rate is high and fluctuating

The population growth rate is zero

The population size is zero

Seite 5

In stage 2...

The birth rate is high and steady

The death rate is rapidly falling

The population growth rate is very high

The population size is rapidly increasing

Seite 6

In stage 3...

The birth rate is rapidly falling

The death rate is slowly falling

The population growth rate is high

The population size is increasing

Seite 7

In stage 4...

The birth rate is low and fluctuating

The death rate is low and fluctuating

The population growth rate is zero

The population size is high and steady

Seite 8

In stage 5...

The birth rate is slowly falling

The death rate is low and fluctuating

The population growth rate is negative

The population size is slowly falling

Seite 9

Why does this happen?

As countries develop, they go through many medical advances and breakthroughs. This is why many poorer countries are usually in the earlier stages, whereas richer countries are usually in the later stages. For example, in stage 2, the birth rate stays high, but the death rate is falling. This means that something has happened to prevent deaths - and is usually medicinal advances.

Seite 10

Stage 1

The birth rate is high because there is no use of contraception here. People also have lots of children because many infants die. The death rate is high because of poor healthcare. The growth rate is zero, and life expectancy is low as few people reach old age, so the population is mostly young.

Seite 11

Stage 2

The birth rate is still high because of the lack of contraception. Because the economy is based around agriculture, children work on farms. The death rate falls due to improvements in healthcare. The growth rate is high and life expectancy has increased, but there are still more young people than old.

Seite 12

Stage 3

The birth rate is rapidly falling due to the emancipation of women and better education. The use of contraception increases and more women work instead of having children. The economy also changes to mainly manufacturing jobs, so less children work on farms. The death rate falls due to medical advances. The growth rate is high and more people are living to older ages.

Seite 13

Stage 4

The birth rate is low because of urbanisation and an improved wealth - people want more possessions. There is now less money for having children. The death rate is low and fluctuating. The growth rate is zero, and life expectancy is high as even more people are living to older ages.

Seite 14

The Rate of Natural Increase

How fast a population grows depends on the rate of natural increase. The rate of natural increase is calculated by subtracting the death rate from the birth rate.

Seite 15

The