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A Growing Population

A Growing Population. Chapter 3 Section 2. Population Growth is Worldwide. The rate of population growth has increased rapidly in modern times. 1960  World population was 3 billion people. 2000  World population doubled to 6 billion people. (40 years later).

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A Growing Population

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  1. A Growing Population Chapter 3 Section 2

  2. Population Growth is Worldwide • The rate of population growth has increased rapidly in modern times. • 1960  World population was 3 billion people. • 2000  World population doubled to 6 billion people. (40 years later)

  3. Population Birthrate and Death Rate • During different historical periods, populations grew at different rates. • Demographers  know that population depends on the birthrate and death rate • Birthrate  the number of live births each year per 1,000 people • Death rate  the number of deaths each year per 1,00 people • By comparing birthrates and death rates, demographers can figure out population growth.

  4. Population Birthrate and Death Rate • For centuries, the world population grew slowly. • No modern machinery = scarce amounts of food • Deaths because of diseases • High birthrate, but also high death rate • The life expectancy (the average number of years that people live) was short. • A hundred yeas ago in the US, men and women usually lived less than 50 years.

  5. Reasons for Population Growth Today • Birthrate has increased dramatically. • The death rate has slowed. • Populations in most countries have grown fast. • In some countries, the population doubles in less than 20 years. • People live longer than ever. • US  women live to about 80 and men to 73 years

  6. Reasons for Population Growth Today • Two scientific developments have made this possible. • 1. New farming methods have greatly increased the world’s food supply. • New varieties of important food crops have been developed • New ways to protect crops against insects • New fertilizers to enrich the soil • These changes in agriculture are called the Gree Revolution.

  7. Reasons for Population Growth Today • 2. Scientists have made advancements in medicine and health. • Today, new medicines and types of surgery treat health problems that used to kill people (i.e. heart disease and serious injuries). • Vaccines to fight diseases such as small pox, polio, and measles • Antibiotics to fight infections • As a result, many more babies are born and stay healthy, and people live many more years. • Population Growth

  8. The Challenges of Population Growth • Growing populations use resources much faster than stable populations. • Some nations, like those in Southwest Asia, face shortages of fresh water and energy. • In Asia and Africa, food supplies cannot keep up with the growing population. • These countries do not have enough money to purchase imported food.

  9. The Challenges of Population Growth • Population growth puts pressure on all aspects of life. • Jobs • Schools • Decent housing • Transportation and sanitation

  10. The Challenges of Population Growth • Rapid population growth also effects the environment. • Forests in areas of India and Pakistan are disappearing. • Wood = building; fuel • Clean air supply • Graphs on Pgs. 62-63

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