Chapter 4 Geography Alive

Introduction—What formed the Great Lakes region? Formed by the movement of glaciers during the last Ice Ageglaciers Make up the world’s largest freshwater ecosystem ecosystem Took thousands of years to form 20% of Earth’s fresh water

The Great Lakes is a WatershedWatershed The Great Lakes is a geographic area in which all of the water in the surrounding region drains. The Great Lakes are so big that they look and act like oceans. In fact, people have called them “the fourth seacoast” of the United States. However, the lakes are filled with fresh water that has little or no salt. That is why they are also called “the sweetwater seas.”

The food web is the relationship between plants and animals in terms of who eats what. Every ecosystem has its own food web. A food web is made up of many food chains. Look at the food chain to the left. How would you interpret the diagram? What would happen to the food chain if the smelt were poisoned by pollution? How might that impact the herring? What might happen to the food chain if the phytoplankton were threatened? The Food Web

Sources of Pollution What are some of the sources of pollution in the Great Lakes? How can people control the amount of pollution in the Great Lakes?

Water Shortages Earth’s population is increasing every year The amount of water is limited Competition for limited water supplies can cause conflict Climate change can shrink water supplies Not all fresh water is safe for human use

Water Use Around the World Which continent uses the most water? Which continents do you think use the most water per person? (you cannot tell from the graph) North America and Europe

Thinking Globally—Getting Water from a Well This well in India draws large crowds every day. In many rural areas, the task of finding water falls to women. They often walk many miles each day to get water for their families.

Freshwater Availability in 2025 Which areas will be at risk for water in 2025? Why will these areas by at risk? (What will influence the availability of fresh water?) What concerns for the future can be drawn from the maps?

The Great Lakes are the world’s largest freshwater ecosystem contain 20% of Earth’s fresh water

Key term Definition glaciers large sheets of ice that moved across the earth’s surface during the last Ice Age

Key term Definition ecosystem a community of all living things in an area

Key term Definition watershed a geographic area that includes all of the land and waterways that drain into a body of water