5-3 Human Population Growth Copyright Pearson Prentice Hall
Historical Overview Like the populations of many other living organisms, the size of the human population tends to increase with time. For most of human existence, the population grew slowly with limiting factors keeping the numbers down. Copyright Pearson Prentice Hall
Limiting Factors that kept population low Food was scarce Many diseases were incurable High infant mortality rate Copyright Pearson Prentice Hall
Historical Overview About 500 years ago, the human population began growing rapidly. Advances in agriculture and industry made life safer and easier. Death rates dropped due to improved sanitation, medicine, and healthcare. Copyright Pearson Prentice Hall
Human Population Growth
Patterns of Population Growth Demography: The scientific study of human populations examines the characteristics of human populations attempts to explain how those populations will change over time. Copyright Pearson Prentice Hall
Patterns of Population Growth Birthrates, death rates, and the age structure of a population help predict why some countries have high growth rates while other countries grow more slowly. Copyright Pearson Prentice Hall
Patterns of Population Growth Over the past century, population growth in the United States, Japan, and much of Europe has slowed. According to demographers, these countries have completed the demographic transition: a dramatic change in birth and death rates. Copyright Pearson Prentice Hall
3 stages of demographic transition Stage 1: high birth and death rates Stage 2: high birth rate, but death rate drops Population increases rapidly. Stage 3: the birthrate decreases Population growth slows. Copyright Pearson Prentice Hall
Patterns of Population Growth Copyright Pearson Prentice Hall
Patterns of Population Growth Population growth depends, in part, on how many people of different ages make up a given population. Age-structure diagrams can predict future growth. Age-structure diagrams show the population of a country broken down by gender and age group. Copyright Pearson Prentice Hall
In the United States, there are nearly equal numbers of people in each age group. This age structure diagram predicts a slow but steady growth rate for the near future. Copyright Pearson Prentice Hall Percentage of Population –64 20–24 0–4 40–44 Age (years) U.S. Population
In Rwanda, there are many more young children than teenagers, and many more teenagers than adults. This age structure diagram predicts a population that will double in about 30 years. Copyright Pearson Prentice Hall –64 20–24 0–4 Age (years) Males Females Rwandan Population 40–44 Percentage of Population
Future Population Growth To predict human population growth, demographers must consider the age structure of each country, as well as the prevalence of life-threatening diseases. If growing countries move toward the demographic transition, growth rate may level off or decrease. Copyright Pearson Prentice Hall
Future Population Growth Copyright Pearson Prentice Hall
Future Population Growth Ecologists suggest that if growth does not slow down, there could be serious damage to the environment and global economy. Economists assert that science, technology, and changes in society may control the negative impact of population growth. Copyright Pearson Prentice Hall
5-3 Copyright Pearson Prentice Hall
5-3 The size of the human population began to increase exponentially after the bubonic plague. development of plowing and irrigation. Industrial Revolution. development of the first cities. Copyright Pearson Prentice Hall
5-3 Which of the following is NOT a potential limiting factor of human population growth? famine medicine war disease Copyright Pearson Prentice Hall
5-3 After the demographic transition is complete, a population grows rapidly. grows slowly. begins a period of rapid decline. stays about the same size as time passes. Copyright Pearson Prentice Hall
5-3 An age-structure diagram shows a breakdown of a population by location and age group. age group and gender. birthrate and death rate. age group and emigration rate. Copyright Pearson Prentice Hall
5-3 Since the mid-1960s, the average annual growth rate of the human population has remained about the same. failed to show a consistent pattern. increased. decreased. Copyright Pearson Prentice Hall
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