Guided Notes on the Human Impact on Land Resources

Chapter 27, Section 2

1. Each year, the typical North American consumes resources equal to the renewable yield from approximately 5 hectares (12.35 acres) of forest and farmland.

2. Mineral and ore deposits found just beneath Earth’s surface can be extracted through mining techniques that involve removing huge amounts of overlying soil and rock.

3. Underground mining is used where mineral resources lie deep under the ground. It is less disruptive to the Earth’s surface than surface mining.

4. Rainwater seeping through mining waste can dissolve toxic metals as well as other chemicals and can move them into nearby streams and rivers, where they will cause water pollution.

5. The Surface Mining Control and Reclamation Act of 1977 requires mining companies to restore the land to its original contours and to replant vegetation in the process known as reclamation.

6. Ecosystems that have high biodiversity are more stable than those with fewer species because they are able to recover more quickly from harmful events such as disease and drought.

7. Monoculture is the planting of just one species of crop in a field.

8. A variety of pesticides have played an important role in boosting food production worldwide by eliminating organisms that destroy crops. However, insect populations can quickly develop resistance to an insecticide. Further problems are created when wind and rain carry pesticides away from a farm and cause pollution in nearby waterways.

9. Whenever fields are plowed and the plants whose roots hold the soil in place are removed, topsoil becomes vulnerable to erosion by wind and water.

10. Clear-cutting of forests may result in the loss of topsoil through erosion and in the clogging of nearby streams with excess sediment.

Describe how selective logging and buffer zones can reduce the negative environmental impacts of deforestation:

In selective logging, workers remove only designated trees, reducing the amount of ground left bare and thus, erosion

Buffer zones slow runoff by catching sediment that has been eroded from bare ground before it reaches streams.

12. 70 percent of the population in North America now lives in urban and suburban areas.

13. When towns and cities expand into rural areas, natural habitats are lost as forests are cleared and wetlands are filled to provide land for roads, houses, and other buildings.

14. Development also takes away land from agricultural use, which puts pressure on the remaining farmland for increased production.

15. When concrete and asphalt cover large land areas, there are fewer opportunities for rainwater to soak into the ground and groundwater supplies are not recharged.

16. Modern landfills are carefully designed to minimize leakage of toxic liquids by using impermeable clay or plastic layers.