6.1 A Changing Landscape

The Effect of Human Activity

› How do our daily activities affect the environment?

Living on Island Earth › Like all organisms, humans affect

the environment when we obtain food, eliminate waste products, and build places to live.

› Human activity has altered roughly half of all the land that’s not covered with ice and snow.

› Might be reaching carry capacity at 7 billion.

Agriculture › Modern agricultural practices allowed

farmers to double world food production over the last 50 years.

› Monoculture, is the practice of clearing large areas of land to plant a single highly productive crop year after year.

Cities and Suburbs

Industrial Growth › The conveniences of

modern life require a lot of energy to produce and power.

› Industries have traditionally discarded wastes from manufacturing and energy production directly into the air, water, and soil.

How can we prevent the overuse of resources?

Sustainable Development

Environmental science… can help us avoid mistakes made by past civilizations.

The lesson of Easter Island: people annihilated their culture by destroying their environment.

Sustainable Resource Use › Using natural

resources in a way that does not cause long-term environmental harm is called sustainable development.

› Cause no harm and use least amount of energy as possible

Wind farms, solar energy, hybrid cars, etc.

Natural resources: vital to human survival

Renewable resources:› Perpetually available: sunlight, wind, wave energy› Renew themselves over short periods: timber, water, soil

These can be destroyed Nonrenewable resources: can be depleted

› Oil, coal, minerals

Natural resources = substances and energy sources needed for survival

6.2 Using Resources Wisely

Soil Erosion › Soil

erosion is the removal of soil by water or wind.

› Ex: dust bowl of the 1930s

How can farmers prevent soil erosion?

Crop Rotation Leaving stems/roots of previous plant Alter shape of land

Soil Erosion

› Farming, overgrazing, seasonal drought, and climate change can turn farmland into desert -desertification.

› Roughly 40 percent of Earth’s land is considered at risk for desertification.

Soil Erosion › Deforestation, or the

loss of forests. Half of the world’s old-growth forests have been lost to deforestation.

› Healthy forests hold soil in place,, absorb carbon dioxide, and help moderate local climate.

› Succession may occur after cutting

Water Pollution › A pollutant is a harmful

material that can enter the biosphere.

› Only 3 percent of Earth’s water is fresh water—most of that is locked in ice at the poles.

› Used for drinking water, industry, transportation, energy, and waste disposal

Biological magnification Increase in concentration of a certain substance throughout a food chain. Ex: Mercury

What are some forms of air pollution?

Smog Acid Rain Greenhouse gases Particulates

Smog › Smog is a gray-brown haze formed by

chemical reactions among pollutants released into the air by industrial processes and automobile exhaust.

Acid Rain

Greenhouse Gases

Particulates