chapter 7Review
Throughout this chapter, we have examined the ways in which the human population changes in response to natural biological factors and in response to other factors that are specifically human in nature. Together, these factors determine the carrying capacity of Earth, the total number of human beings that the world can support. People in the developed world are currently exhibiting very different behavior from those in the developing world. In the developed world, population growth has almost stopped while consumption of resources is still quite high. In the developing world, growth rates, while slowing, are still high, and consumption of resources is still rather low. As the world becomes more urban, and the impacts of development and consumption from larger numbers of people increase, the challenge is to achieve sustainable growth while also promoting the improvement of living conditions in the developing world.
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Module 22 Human Population Numbers
Explain factors that may potentially limit the carrying capacity of humans on Earth.
Scientists disagree about the size of Earth’s carrying capacity for humans. Some scientists believe we have already exceeded that carrying capacity. Others believe that innovative approaches and new technologies will allow the human population to continue to grow beyond the environmental limits currently imposed by factors such as the supply of food, water, and natural resources.
Describe the drivers of human population growth.
The human population is currently 7.2 billion people, and it is growing at a rate of about a million people every 5 days. If we think of the human population—
Read and interpret an age structure diagram
Age structure diagrams are visual representations of age structures for males and females. Each horizontal bar in the diagram represents an age group. The total area of all the bars in the diagram represents the size of the whole population. A country with more younger people than older people has an age structure diagram that is widest at the bottom and narrowest at the top. This is often called a population pyramid and is typical of developing countries. Developed countries tend to have closer to an even age distribution and their age structure diagrams are more vertical or column-
Module 23 Economic Development, Consumption, and Sustainability
Describe how demographic transition follows economic development.
A number of countries have undergone a demographic transition as their economies have modernized. Economic development generally leads to increased affluence, increased education, less need for children to help their families generate subsistence income, and increased family planning. These factors have reduced the average size of families in developed countries, which leads to slower population growth. Eventually, population size may even decline.
Explain how relationships among population size, economic development, and resource consumption influence the environment.
Most population growth today is occurring in developing countries. Only one-
Explain why sustainable development is a common but elusive goal.
Sustainable development attempts to raise standards of living without increasing environmental impact. The Millennium Ecosystem Assessment is a blueprint for sustainable development.