population growth Flashcards
What is exponential growth?
A pattern where the growth rate constantly increases. It is often shown as a J-curve graph
What is expected to happen after the world population has peaked?
This should be followed by a more stable period of zero growth or even natural decrease (ND)
What is happening to the rate of population growth today?
Growth rates are slowing down (although the numbers being added daily are still high), so the shape of the graph is levelling off into an S-curve
What is birth rate (BR)?
The number of babies born per 1000 people per year
What are birth rates like today?
Vary between 5 per 1000 per year and 40 per 1000 per year, depending on the country concerned
What have birth rates been like in the past?
Figures have been as high as 50 per 1000 per year
Why do such high birth rates rarely occur now?
Because of the availability of birth control
What is death rate (DR)?
The number of deaths per 1000 people per year
What are typical death rates?
Between 5 per 1000 people per year and 20 per 1000 per year
What could significantly increase the death rate of a country?
An epidemic, famine, or war
Why are birth and death rates expressed as ‘per 1000’?
So that the figures for countries of different sizes can be compared
What is natural change?
The difference between birth rate and death rate in a country, given as a percentage
What is natural change a good measure of?
It is a useful measure of a population’s growth or decline and, when comparing countries, can be used to find reasons to explain their population statistics
What is natural increase (NI)?
When the birth rate is greater than the death rate
What is natural decrease (ND)?
When the death rate is greater than the birth rate
