EHST 2110 - ECU Actual Exam 1 Questions and
answers Update RATED A+ NEW EDITION
Environmental Refugees
People forced to leave their country due to environmental problems like drought,
flooding, or desertification
Population Growth Effect
More population → more food demand → more land conversion → ecosystem damage
Overgrazing
Excessive livestock feeding that damages vegetation and soil
Rangeland Statistics
40% of Earth is rangeland; 50% is lightly/moderately degraded; 5% is impossible to
restore
Effects of Overgrazing
Loss of plant species, weed invasion, soil erosion, and water pollution
Deforestation (vs. Overgrazing)
Removal of trees rather than livestock damage
Desertification (vs. Overgrazing)
Large-scale land degradation in dry areas
Soil Erosion
Loss of soil by wind or water transport
Topsoil
Nutrient-rich surface soil layer; takes 200-1000+ years to form 1 inch
T-Value
Maximum soil loss rate that still allows long-term productivity
, Dust Bowl
1930s Great Plains event caused by drought and poor farming leading to massive
topsoil erosion
Deforestation
Permanent reduction of forest crown cover below 10%
Main Cause of Deforestation
Agriculture (especially cattle ranching, soy, palm oil)
Deforestation Cause & Effect
Deforestation → erosion → flooding → habitat loss
Desertification
Land degradation in arid/semiarid areas due to climate variation and human activity;
affects over 1 billion people
Wetlands
Areas with hydric soils, saturated conditions, and hydrophytic vegetation
Main Cause of Wetland Loss
Agricultural drainage (80% of loss)
Wetland Functions
Flood control, pollution filtering, wildlife habitat
Invasive Species
Non-native species that cause ecological or economic harm
Island Vulnerability
75% of U.S. plant and bird extinctions occurred in Hawaii
Biodiversity Importance
Increases ecosystem stability, supports medicine (25% plant-derived pharmaceuticals),
and food security
answers Update RATED A+ NEW EDITION
Environmental Refugees
People forced to leave their country due to environmental problems like drought,
flooding, or desertification
Population Growth Effect
More population → more food demand → more land conversion → ecosystem damage
Overgrazing
Excessive livestock feeding that damages vegetation and soil
Rangeland Statistics
40% of Earth is rangeland; 50% is lightly/moderately degraded; 5% is impossible to
restore
Effects of Overgrazing
Loss of plant species, weed invasion, soil erosion, and water pollution
Deforestation (vs. Overgrazing)
Removal of trees rather than livestock damage
Desertification (vs. Overgrazing)
Large-scale land degradation in dry areas
Soil Erosion
Loss of soil by wind or water transport
Topsoil
Nutrient-rich surface soil layer; takes 200-1000+ years to form 1 inch
T-Value
Maximum soil loss rate that still allows long-term productivity
, Dust Bowl
1930s Great Plains event caused by drought and poor farming leading to massive
topsoil erosion
Deforestation
Permanent reduction of forest crown cover below 10%
Main Cause of Deforestation
Agriculture (especially cattle ranching, soy, palm oil)
Deforestation Cause & Effect
Deforestation → erosion → flooding → habitat loss
Desertification
Land degradation in arid/semiarid areas due to climate variation and human activity;
affects over 1 billion people
Wetlands
Areas with hydric soils, saturated conditions, and hydrophytic vegetation
Main Cause of Wetland Loss
Agricultural drainage (80% of loss)
Wetland Functions
Flood control, pollution filtering, wildlife habitat
Invasive Species
Non-native species that cause ecological or economic harm
Island Vulnerability
75% of U.S. plant and bird extinctions occurred in Hawaii
Biodiversity Importance
Increases ecosystem stability, supports medicine (25% plant-derived pharmaceuticals),
and food security
