Population Distribution
Introduced| English | Meaning |
|---|---|
| population distribution/ˌpɒpjʊˈleɪʃn ˌdɪstrɪˈbjuːʃn/ | The spatial pattern of where people live across an area. |
| arithmetic density/əˈrɪθmətɪk ˈdensɪti/ | The total population divided by the total land area of the territory being measured. |
| physiological density/ˌfɪzɪəˈlɒdʒɪkl ˈdensɪti/ | The total population divided by the area of arable land, indicating potential pressure on land suitable for crops. |
| agricultural density/ˌæɡrɪˈkʌltʃərəl ˈdensɪti/ | The number of farmers divided by the area of arable land in the territory being measured. |
People are spread unevenly
- Population distribution 人口分布 describes where people live on Earth.
- Most people cluster in a few favourable places, and huge areas are nearly empty.
- About two-thirds of humanity lives in just a handful of regions.
Where people cluster
- People gather in mid-latitudes, on low-lying land, and near water.
- Fertile soil, mild climate, and coasts or rivers all attract settlement.
- Deserts, high mountains, and frozen poles repel it.
Shibuya Crossing, Tokyo: a photograph shows crowding at one moment, not resident population per square kilometre
Most people live in deserts, high mountains, and polar regions.
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People cluster in mid-latitude, low-lying, well-watered land; harsh areas repel settlement.
Select all factors that attract dense settlement.
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Soil, climate, and water attract people; polar cold repels them.
Three densities
- Arithmetic density 算术密度 = people ÷ total land area.
- Physiological density 生理密度 = people ÷ arable (farmable) land — a better guide to food pressure.
- Agricultural density 农业密度 = farmers ÷ arable land; a low value suggests efficient, mechanised farming.
Which density measure?
Sort each definition as arithmetic, physiological, or agricultural density.
Physiological density divides the population by...
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Physiological density = people ÷ farmable land, so it shows pressure on food supply.
Total population divided by total land area is ____ density.
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Arithmetic density is the simplest measure — everyone divided by all the land.
Match each density to what it divides by.
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Arithmetic ÷ all land; physiological ÷ farmable land; agricultural = farmers ÷ farmable land.
Do not confuse the three densities. Arithmetic uses all land; physiological uses only farmable land; agricultural counts only farmers. A country can have low arithmetic density but high physiological density if most of its land is desert.
Egypt looks empty at arithmetic density, because most of it is Sahara desert. But almost everyone crowds into the thin Nile valley, so its physiological density (people per farmable hectare) is one of the highest on Earth.
Population distribution is where people live — mostly clustered in mid-latitude, low, well-watered places. Three measures compare crowding: arithmetic (all land), physiological (farmable land), and agricultural (farmers per farmable land).
Write from a physiological density of 250
- A country has 2 million people.
- Its land area is 40000 square kilometres, of which 8000 are arable.
What is the physiological density?
Physiological density is population divided by arable land.
What is the physiological density?
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2 million divided by 8000 is 250. Other options — 50 (the arithmetic density); 8000 (the arable area).