Population growth and structure

Population growth and structure

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Caption: : The demographic transition model and population shapes.

World population

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

Caption: : This graph shows the world population from 1820->2000.

Birth rate + Death rate

The birth rate is the amount of babies born per 1000 people per year.

The death rate is the amount of deaths per 1000 people per year.

Natural increase and decrease

When the birth rate is higher than the death rate, this is called the natural increase. When the death rate is higher than the birth rate, this is called the natural decrease.  Although the birth rate and death rate affect the population size, migration can also cause a surge in population sizes.

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The Demographic Transition Model

The demographic transition model shows population change over time. It studies how birth rate and death rate affect the total population of a country.

Caption: : Get ready for five slides of this joy.

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.

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

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

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

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

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 of the DTM, 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.

Now, for the joy of structures.

Stage 1

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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.

Stage 2

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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.

Stage 3

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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.

Stage 4

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

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Stage 5

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The birth rate is slowly falling - there's less money thanks to dependent old people. The death rate is low and fluctuating, population growth is negative and there are many more older people.

Caption: : Yes, okay, it doesn't look like the others. I couldn't find a good one online so I made it on paint. How cool am I?

Key words:

Population structure -> how many people of each age group and gender. Emancipation of women -> women having a more equal place in society Urbanisation -> people moving to urban areas (natural increase/decrease, birth/death rate are also key words - but these were included earlier.)