Humans in the Biosphere How have human activities shaped local and global ecology?

The Effect of Human Activity Agriculture Benefit: food production Environmental cost: impact on fresh water and fertile soil

The Effect of Human Activity 2. Development Benefit: higher standard of living Environmental cost: production of lots of wastes

The Effect of Human Activity 3. Industrial growth - Benefit: conveniences of modern life - Environmental cost: requires lots of energy to produce and power products.

Question: How might more productive agricultural practices affect a developing nation’s population? Its environmental health?

Sustainable Development Renewable resources: resources that can be produced or replaced by a healthy ecosystem Ex. Plants, trees, sun… Nonrenewable resources: resources that can not be replaced within a reasonable amount of time. Ex: fossil fuels( coal, oil, natural gas), water

Sustainable development Providing for human needs while preserving the ecosystem that produce natural resources. Causes no long-term harm to the soil, water and climate Consume little energy and material as possible Flexible to survive environmental stresses

Using Resources Wisely 3 major environmental concerns: Soil erosion Water pollution Air pollution

Soil Healthy soil supports both agriculture and forestry Topsoil – contains nutrients and minerals essential to growth Can be a renewable resource if managed properly Soil erosion – removal of soil by water and wind (over farming, over grazing…)

Soil erosion Desertification – turning farmland into dessert by over farming, over grazing, seasonal drought and climate change Deforestation – loss of forests, trees hold soil in place

Soil Use and Sustainability Leave stems and roots in ground Crop rotation Altering the shape of the land- contour farming

Freshwater Resources Freshwater is usually a renewable resource but if not removed faster than can be replaced: nonrenewable Aquifer: underground water reserve

Water pollution Harmful materials that enter the biosphere and water source Point source pollution: from single source like an oil spill Nonpoint sources – pollution from smaller sources, such as oil and grease off streets Primary pollution sources Agricultural chemicals, residential sewage and nonpoint sources

Water quality and sustainability Watershed conservation – clean up pollution Sewage treatment IPM – integrated pest management, instead of pesticides (ladybugs) Conserving water – drip irrigation

Biological Magnification Pollutant is picked up by an organism and not broken down but collects in body tissues. As food eats food, the pollutant concentration increases ten fold. At highest trophic levels, concentrations may reach 10 million times their concentration. Ex. DDT, bold eagles, mercury, pregnant women

Acid Rain Steps: Coal –burning power plants put smoke high into the atmosphere The smoke contains high levels of sulfur The smokestacks were to dissipate the smoke, backfired Smoke combines with water vapor =sulfuric acid Acidified precipitation = ACID RAIN

Acid Rain

Effects of Acid Rain Most prominent in the Northeastern United States and Southeastern Canada Why… pH scale, below 7 = Acid Under 5, results in damage to organisms, statues…

Effects of Acid Rain

Ozone Layer O3, protective shield in upper atmosphere Layer is thinning and disappearing Allows more UV rays into environment Why is this an issue?

Destruction of Ozone CFC’s – Chlorofluorocarbons Heat exchanger, refrigerator coolant, aerosol propellant, foaming agents UV rays are strong enough to break the bonds in CFC’s, releasing chlorine atoms, which in turn react with ozone, destroying it Limit or ban use of CFC’s US – limit CFC’s in aerosol’s

Ozone Depletion CFCs escape into amosphere CFCs destroy ozone More UV radiation reaches Earth’s surface Skin cancer cases increase

Good and Bad Ozone Good Bad (forms when sun and emissions react) Protective layer, absorbs UV rays Between 11 – 16 miles above sea level Bad (forms when sun and emissions react) Corrosive, reactive gas Pollutant at surface levels Irritates and damages lungs and eyes, suppresses immune system