Chapter 6 Humans in the Biosphere

Chapter 6 Section 1 A Changing Landscape

The Effects of Human Activity Human activities such as agriculture, development and industry have an effect on the quality of Earth and its resources –Agriculture – creates a dependable supply of food that can be stored Monoculture – the practice of clearing large areas of land to plant a single, highly productive crop

The Effects of Human Activities Cont. –Development Dense human communities produce lots of waste Development consumes farmland and divides natural habitats –Industrial Growth Our modern conveniences require a lot of energy to produce –Energy is obtained by burning fossil fuels – coal, oil, and natural gas Industrial waste is often discarded directly into the air, water, and soil

Renewable Resources Resources that can regenerate if they are alive or be replenished by biochemical cycles if they are nonliving Resources that cannot be replenished by natural processes –Fossil fuels, coal, oil, natural gas Nonrenewable Resources

Sustainable Resource Use Sustainable Development – a way of using natural resources to meet human needs while allowing us to preserve our resources and not cause long-term environmental harm –Should not harm soil, water, or climate and should use as little energy as possible –Should not just enable people to survive but should improve their situation

Chapter 6 Section 2 Using Resources Wisely

Soil Resources Healthy soil supports agriculture and forestry Topsoil – a renewable resource –The mineral and nutrient-rich portion of soil –Good topsoil is produced by the long term interactions of the soil and the plants growing in it

Soil Erosion Soil Erosion – the removal of soil by water or wind –Desertification – when farming, overgrazing, and drought, in dryer climates, turns farmland into desert –Deforestation – loss of forests Can lead to severe soil erosion, especially on mountainsides

Freshwater Resources Usually considered a renewable resource –Remember: Only 3% of Earth’s water is fresh! Water pollution –Oil spills –Factories –Run-off from streets

Industrial and Agricultural Chemicals Large scale monoculture uses a large amount of pesticides and insecticides –DDT – common pesticide that gets into water Biological Magnification – when a pollutant is picked up by an organism and it is not broken down or eliminated from its body –Concentrations are greater in higher trophic levels

Atmospheric Resources Pollutants – a harmful material that can enter the biosphere through the land, air, or water Acid Rain – mixture of water vapor and chemical compounds –Harmful to plants, soil, etc.

Chapter 6 Section 3 Biodiversity

The Value of Biodiversity Biodiversity – the total of the genetically based variety of all organisms in the biosphere –Ecosystem diversity – the variety of ecosystems and habitats –Species diversity – the number of different species in the biosphere

Threats to Biodiversity Humans can reduce biodiversity by: –altering habitats –hunting species to extinction –introducing toxic compounds –introducing new species to environments

Chapter 6 Section 4 Charting a Course for the Future

Ozone Depletion Ozone Layer – km above Earth’s surface, high concentration of ozone gas –Ozone absorbs much of the harmful UV rays –Being damaged due to CFC’s (chloroflourocarbons) Aerosol cans, coolants in freezers, plastic foams –CFC’s have been banned and we should see the hole in the ozone disappear in about 50 years

Global Climate Change Global Warming – an increase in the average temperature of the biosphere –Due in part to human activities Releasing carbon dioxide into the air increasing greenhouse gasses Average temperatures will increase causing sea levels to rise – possibly flooding coastal communities