2 Setting the SceneImagine that you go to school in Tokyo, Japan. Every day you ride the train to school, jammed in so tight that station guards have to push people in the train just so the doors can close.
3 Population Distribution Population means the total number of people in an area. The world’s population is currently between 6 and 7 billion!Population distribution describes how people are spread out across the world.
4 Population Distribution Demographers are scientists that study population. They find trends about where people tend to live.Most people live along rivers and lakes because they provide easy transportation and water for drinking and farming.
5 Population DensityMore than 81% of the Earth’s population lives in Asia, Europe and North America, though these continents make up about ½ of the Earth’s land.These continents have large areas of fertile soil, favorable landforms, plenty of fresh water, rich natural resources and good climates.
6 Population DensityThe average number of people who live in a square mile is called population density.Japan has a high population density because there are so many people in a small space. (25,000/mile²)Canada’s cold weather and short farming season keeps the population density low. (3/mile²)
7 Growing NeedsDemographers measure population density by dividing the number of people in a place by the number of square miles of that place.A state like New York has a much lower population density that one might think. Though many people live in the cities, very few people live in the countryside there.
8 Population Growth Today the Earth’s population is steadily growing. The Birthrate is the number of live births each year per 1,000 people.Demographers can figure out a population’s growth by comparing the birthrate to the death rate.
9 Population GrowthFor most of world history, the world population grew slowly due to disease and lack of food.However, in the last 200 years the Earth’s population has multiplied by almost 7 times!
10 Population GrowthThis growth is mainly caused by medical advances and the Green Revolution.The Green Revolution is an advance in farming that has allowed farmers to produce more food and protect it from pests.
12 The Movement of PeopleHumans have always been on the move. When people move from place to place it is called migration.Immigrants are people who leave one country and move to another.For centuries hundreds of thousands of people have immigrated to the U.S.
13 Push and PullDemographers use the “push-pull” theory to explain immigration.It says that people migrate because certain things push them to leave, like a bad economy, a war, or to escape a harsh government.For example, people have been escaping from Cuba since Castro’s Communist government took over there in 1959.
14 Push and PullLikewise, the hope for better living conditions may pull people to a different country.Throughout its history America has pulled in immigrants with hopes of a better life here.
15 Other Types of Immigration Sometimes people are forced to migrate. Australia was colonized by English convicts who served out their sentences there and settled there when they had served their time.
16 The World becomes more Urban In recent years the most major migrations have been from the country (rural areas) to large cities (urban areas.) This movement is called Urbanization.In the past, most people were farmers, hunters and fishers. Now fewer people are needed to grow food, and many of these people move to large cities.
17 Growing CitiesMost people move to cities to find a better life for their families.However, cities around the world are growing faster than they can keep up with. They cannot provide enough jobs, schools or houses with so many people moving in.