Bio Chapter 6 Clean Study Guide - Chapter 6 Section 1 A...

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Chapter 6 Section 1: A Changing Landscape The first humans to settle Hawaii came from Polynesia about 1600 years ago. They cut trees to plant farms, and they introduced nonnative plants, pigs, chickens, dogs, and rats. This combination drove many native plant and animal species to extinction. Yet for centuries Hawaii’s ecosystems provided enough fresh water, fertile soil, fish, and other resources to keep the society self-sufficient. What happened next is an important lesson on managing limited resources. How do our daily activities affect the environment? Humans affect regional and global environments through agriculture, development, and industry in ways that have an impact on the quality of Earth’s natural resources, including soil, water, and the atmosphere. Beginning in the late 1700s, new waves of settlers arrived in Hawaii. They imported plants and animals that became invasive pests. They cleared vast tracts of forest to grow sugar cane, pineapples, and other crops that required lots of water. They also converted land for housing and tourism. Waikiki Beach, for example, is surrounded by built-up areas that support tourism. The effect of these activities on Hawaii’s ecosystems and its human inhabitants show what happens when a growing human population does not adequately manage natural resources. Like all other organisms, humans affect the environment when we obtain food, eliminate waste products, and build places to live. Most of us probably don’t think of land, food, and water as limited resources. But today human activity has used or altered roughly half of all the land that’s not covered with ice and snow. Some people suggest that as the global population reaches 7 billion people, we may be approaching the carrying capacity of the biosphere for humans. Modern agricultural practices have enabled farmers to double world food production over the last 50 years. Monoculture , for example, is the practice of clearing large areas of land to plant a single highly productive crop year after year. Monoculture enables efficient sowing, tending, and harvesting of crops using machines. However, agriculture impacts natural resources, including fresh water and fertile soil. Fertilizer production and farm machinery also consume large amounts of fossil fuels. As modern society developed, many people chose to live in cities. Then, as urban centers became crowded, people moved to suburbs. This development has environmental effects. Dense human communities produce lots of wastes that, if not disposed of properly, can affect air, water, and soil resources. In addition, development consumes farmland and divides natural habitats into fragments. Development in Florida, for example, has lead to fragmentation of the forests there. The conveniences of modern life require a lot of energy to produce and power. Most of this energy is obtained by burning fossil fuels—coal, oil, and natural gas—and that affects the environment.

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