Fixing a Hole in the Sky Ozone is a naturally occurring molecule that absorbs and redirects harmful UV radiation. In the 1970s, Mario Molina and Sherwood Rowland discovered that CFCs were rapidly destroying ozone in the stratosphere. Today, most nations have banned CFCs, and the ozone hole is expected to close up around 2050. Talk About It Should environmental scientists’ discoveries about the natural world influence human activity? If so, how?

What Is Environmental Science? Chapter 1: Our Island, Earth What Is Environmental Science? The study of our planet’s natural systems and how humans and the environment affect one another The environment includes all living and nonliving things with which organisms interact. Understanding the interactions between humans and the environment is the first step to solving environmental problems. National Marine Fisheries Service scientists studying whether commercial boats are harming endangered killer whales

Chapter 1: Our Island, Earth Natural Resources Natural resources are materials and energy sources found in nature that humans need to survive. Renewable resources: Naturally replenished over short periods Nonrenewable resources: Naturally formed more slowly than we use them. Renewable resources can become nonrenewable if used faster than they are replenished.

Cleaning the Tides of San Diego and Tijuana The heavily polluted Tijuana River crosses over from Mexico to the U.S. and empties into the Pacific Ocean near San Diego, California, forcing frequent beach closures. Pollution sources include U.S.-owned factories as well as Mexican farms, homes, and sewage treatment plants. In 1990 the U.S. and Mexico agreed to build a wastewater treatment plant, but construction has yet to be completed. Talk About It Why is the pollution problem in the Tijuana River particularly difficult to solve? How does this case illustrate the connections between the environment, the economy, and government policy?

Consumer and Corporate Responses Chapter 2: Economics Consumer and Corporate Responses Changing consumer values can drive corporations to pursue sustainability. Ecolabeling is an example of a corporate response to the call for sustainable goods and services. Did You Know? Organic farming is one of the fastest-growing segments of U.S. agriculture. Land devoted to growing organic has expanded by about 15% each year since 2002.

International Environmental Policy Chapter 2: International Environmental Policy and Approaches International Environmental Policy Environmental issues often involve more than one nation. International organizations promote cooperation between nations: The United Nations The European Union The World Trade Organization The World Bank

The Gulf of Mexico’s Dead Zone Nutrient-rich runoff causes plankton blooms and hypoxia—low oxygen levels—in the Gulf of Mexico. Hypoxia kills or displaces marine organisms, causing a decline in the fisheries and the fishing industry. U.S. government and farmers debate the need to cut down on fertilizer use. Talk About It Do you think the distance between the source of the nitrogen and phosphorus and the dead zones themselves makes it difficult to manage this problem? Why or why not?

Tectonic Plates There are three major types of plate boundary: Chapter 3: Earth’s Spheres Tectonic Plates There are three major types of plate boundary: Divergent Transform Convergent

Divergent and Transform Plate Boundaries Chapter 3: Earth’s Spheres Divergent and Transform Plate Boundaries Divergent boundaries: Rising magma pushes plates apart. Transform boundaries: Plates slip and grind alongside one another. Divergent plate boundary Transform plate boundary

Convergent Plate Boundaries Chapter 3: Earth’s Spheres Convergent Plate Boundaries Plates collide, causing one of two things to happen: Subduction: One plate slides beneath another. Mountain-building: Both plates are uplifted.

The Hydrosphere Consists of Earth’s water Chapter 3: Earth’s Spheres The Hydrosphere Consists of Earth’s water Most of Earth’s water (97.5%) is salt water. Only 0.5% of Earth’s water is unfrozen fresh water usable for drinking or irrigation. Earth’s available fresh water includes surface water and ground water. Greenlaw Brook, Limestone, Maine Did You Know? If it is depleted, groundwater can take hundreds or even thousands of years to recharge completely.

Chapter 3: Earth’s Spheres The Water Cycle

Finding Gold in a Costa Rican Cloud Forest Golden toads lived in Costa Rica’s Monteverde cloud forest. Golden toads were first described in 1964. They were extinct by 1989. Talk About It Why is the extinction of the golden toad a global concern?

Biotic and Abiotic Factors Chapter 4: Studying Ecology Biotic and Abiotic Factors Biotic factors: Parts of an ecosystem that are living or used to be living Abiotic factors: Parts of an ecosystem that have never been living Did You Know? Decaying organisms are biotic factors as long as their structure remains cellular.

Habitat The specific environment in which an organism lives Chapter 4: Studying Ecology Habitat The specific environment in which an organism lives Habitats provide an organism with resources—anything an organism needs to survive and reproduce, including food, shelter, and mates.

Population Distribution Chapter 4: Describing Populations Population Distribution How organisms are arranged within an area: Random distribution: Organisms arranged in no particular pattern Uniform distribution: Organisms evenly spaced Clumped distribution: Organisms grouped near resources; most common distribution in nature