Biology Chapter Sixteen: Human Impact on Ecosystems

Section One: Human Population Growth and Natural Resources Earth’s Human Population Continues to grow What is the Earth’s carrying capacity? Current World Population: 7.4 Billion Carrying capacity has increased with agriculture, transportation, and medical advances and sanitation Technology and antibiotics has also helped to increase carrying capacity

Section One: Human Population Growth and Natural Resources

Section One: Human Population Growth and Natural Resources Human Population and Natural Resource Pressure More humans= more use of natural resources Nonrenewable resources: resources that are used faster than they are formed Oil and Coal Renewable Resources: cannot be used up or replenish themselves over time Wind and Solar Energy Pollution and over use threaten drinking water as a renewable resource

Section One: Human Population Growth and Natural Resources Resource Management and Ecological Footprint Practicing Sustainable Usage of Resources Ecological Footprint: the amount of land necessary to produce and maintain enough food and water, shelter, energy, and waste

Section Two: Air Quality Pollution: any undesirable factor that is added to air, water, or soil Air Pollutants Smog: a type of air pollution caused by the interaction of sunlight with pollutants produced by fossil fuel emissions Particulates: microscopic bits of dust, metal, and unburned fuel that are produced by many different industrial processes Can be inhaled Ground Level Ozone Produced by reaction of oxygen gas and nitrogen oxide Can be harmful to humans

Section Two: Air Quality Air Pollutants Acid Rain: a type of precipitation produced when pollutants in the water cycle cause rain pH to drop below normal levels

Section Two: Air Quality How Air Pollution Affects the Biosphere Greenhouse Effect: occurs when greenhouse gases absorb reradiated energy by Earth’s surface and slow the release of this energy from Earth’s atmosphere Greenhouse gases: carbon dioxide, water, CFCs, and methane Make it harder for heat to be released back into the atmosphere Contributes to excessive global warming Global Warming: the trend of increasing global temperatures Threatens ecosystems

Section Two: Air Quality

Section Two: Air Quality

Section Three: Water Quality Water Pollution Raw sewage, toxic chemicals, and trash can all enter the water system Can lead to algal blooms and eutrophication Indicator Species: a species that provides a sign of the quality of the ecosystem’s environmental condition Amphibians

Section Three: Water Quality Biomagnification A process in which a pollutant moves up the food chain, as predators eat prey, accumulating in higher concentrations in the bodies of the predators Has the greatest effect on top level consumers

Section Four: Threats to Biodiversity Preserving Biodiversity Decreasing biodiversity has an effect on all living organisms and ecosystems Effects are long-term Extinctions is forever

Section Four: Threats to Biodiversity Causes of Loss of Biodiversity Habitat Loss Habitat Fragmentation: a barrier forms that prevents an organism from accessing its entire home range Some states have built overpasses or underpasses for wildlife Introduced (Invasive) Species Any organism that was brought to the ecosystem as a result of human actions Usually have no natural predators and can outcompete the native species Can cause economic damage

Section Four: Threats to Biodiversity

Section Four: Threats to Biodiversity

Section Five: Conservation Sustainable Development A practice in which natural resources are used and managed in a way that meets current needs without hurting future generations Selective cutting instead of clear cutting trees Fishing industry examples: Rotation Fishing Gear Review Harvest Reduction Fishing Bans

Section Five: Conservation Conservation through Umbrella Species Conservation practices usually focus on one species but benefit entire ecosystems Umbrella Species: protection of one species leads to protection of a wide range of other species Ex. Manatees and marine ecosystems

Section Five: Conservation Protecting Earth’s Resources and Our Future Earth’s resource provide $30 trillion a year in services Environmental Protection Agency (EPA) Environmental Laws (Clean Air Act) National Parks Controlling Birth Rate Using Less and Wasting Less