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Section 6-1: A Changing Landscape
Among the human activities that have transformed the biosphere are hunting and gathering, agriculture, industry, and urban development.
Section 6-2: Renewable and Nonrenewable Resources
Regardless of whether they are held in common, environmental resources can be classified into two types: renewable and nonrenewable.
Human activities affect the supply and the quality of renewable resources, including resources such as land, forests, ocean resources, air, and water.
Section 6-3: Biodiversity
Biodiversity is one of Earth's greatest natural resources. Many species have provided us with foods, industrial products, and medicines—including painkillers, antibiotics, heart drugs, antidepressants, and anticancer drugs.
Human activity can reduce biodiversity by altering habitats, hunting species to extinction, introducing toxic compounds into food webs, and introducing foreign species to new environments.
Today, conservation efforts focus on protecting entire ecosystems as well as single species. Protecting an ecosystem will ensure that the natural habitats and interactions of many different species will be preserved at the same time.
Section 6-4: Charting a Course for the Future
Many biologists are concerned about the biological effects of two types of global change: the thinning, or depletion, of the ozone layer and global warming.