41 terms

Chapter 1.4 Population and Settlement - Population density and distribution

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Antarctica is the only continent where
everyone is a visitor
the way people are spread out over the Earth`s land surfaces
population distribution
how many people live in an area, usually one square kilometre, or 1 km2
population density
describes places where many people live
densely populated
describes places where very few people live
sparsely populated
describes places where very nobody lives
uninhabited
In cities
many people live very close together
In other parts of the world
people are more scattered across the landscape
Most countries
do not impose restrictions to its people so they are free to move elsewhere in search of a higher standard of living
One of the reasons for uneven population distribution is
there is twice as much land in the northern hemisphere as there is south of the Equator.
At present, half of the world`s people
live in urban areas
The most densely populated areas of all are
urban settlements, towns and cities
Singapore is one of only ______________ countries in the world that has all its people living in ______ areas
10 and urban
reasons why people live in certain places
1. flat or gently sloping land makes it possible to farm and build towns, roads and railways
2. when floods occur, most rivers deposit alluvium which is rich in the minerals needed by plants for growth
3. coasts and other waterside locations can be developed into ports with trading links to other countries
4. fertile soil
5. climate
6. fossil fuels
7. mineral deposits
8. fishing
9. fresh water
At present, __________% of all people on Earth live within 100 km of a coast
40
other reasons why towns and cities grow rapidly increasing size and density of population
1. employment opportunities for people
2. migration of people from other less favourable places
Singapore
is one of only 10 countries in the world that has all its people living in urban areas
Singapore is an island heavily urbanised
1. ships refuel
2. ships discharge load their cargoes here
3. creates thousands of jobs
Only _________% of all adults of working age are unemployed in Singapore
2
Singapore 28 new towns
four of these are 200 000 inhabitants each
two-thirds of all Singaporeans
live in new towns
The largest desert in the world took its name from the Arabic word for desert
Sahara
Is another arabic word, meaning `on the edge`of the desert
Sahel
This is the process of the soil becoming less fertile
soil degradation
Soil can be eroded and carried elsewhere by strong winds
erosion
In a hot, dry climate, where evaporation rates are high, they are present in the water and can build up in the soil, causing it to become toxic to plants
salinisation
Soil is leached when heavy rain dissolves valuable plant nutrients in the topsoil, then washes them downwards below the depth that plant roots can reach
leaching
Is the process by which semi-arid environments become desert-like because they are areas next to deserts
desertification
The area to the south of the Sahara is experiencing increasingly
severe famine
Why is the Sahel sparsely populated
1. Sahel's population doubles every 20 years-faster than its increase in food production
2. aid agencies now subsidise 30% of food in the region-many people now dependent on food aid
3. many farmers grow cash crops on their best land instead of food
4. many farming methods unsustainable - annual crop yields
5. few natural resources to stimulate local industry and provide exports to increase wealth
6. anopheles mosquito on the increase, so more people suffering from malaria
7. region includes three of the four poorest countries on Earth
The Sahel today is known as Africa's
famine belt
Main economic activity in the Sahel
Farming
Main food crops in Sahel
millet, sorghum and cowpea
Main cash crops
groundnuts (peanuts) and cotton
Sahel population
nomadic herders, who migrate northwards during the wet season then return when that area becomes too dry. Many farmers now use cell phones to get weather forecasts and move their animals to places where rain is predicted to fall.
Sahel worst famine
many cattle die from starvation and thirst, there is not enough water to irrigate fodder crops
natural factors of desertification
1. lower total annual rainfall
2. less protective natural vegetation
3. fewer plant roots to bind the soil
4. heavy rain causes rapid erosion of exposed soil
5. greater evaporation
human factors of desertification
1. tree cut down for fuelwood and building materials
2. over-cultivation due to economic pressure to grow more cash crops- leads to soil degradation and erosion
cash crop
a crop grown to sell for profit
soil degradation happens in 3 ways
erosion, salinisation and leaching
Desertification is a global problem
1. one-third of the world's total land area is already desertified or is under serious threat
2. climate change is a major natural cause raising global temperatures and changes seasonal rainfall patterns
3. 20% world's population lives with the threat
4. an estimated 850 million people are directly affected by it mostly in Africa