Presentation on theme: "Humans in the Biosphere"— Presentation transcript:
1 Humans in the Biosphere How have human activities shaped local and global ecology?
2 The Effect of Human Activity AgricultureBenefit: food productionEnvironmental cost: impact on fresh water and fertile soil
3 The Effect of Human Activity 2. DevelopmentBenefit: higher standard of livingEnvironmental cost: production of lots of wastes
4 The Effect of Human Activity 3. Industrial growth - Benefit: conveniences of modern life - Environmental cost: requires lots of energy to produce and power products.
5 Question:How might more productive agricultural practices affect a developing nation’s population?Its environmental health?
6 Sustainable Development Renewable resources: resources that can be produced or replaced by a healthy ecosystemEx. 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
7 Sustainable development Providing for human needs while preserving the ecosystem that produce natural resources.Causes no long-term harm to the soil, water and climateConsume little energy and material as possibleFlexible to survive environmental stresses
8 Using Resources Wisely 3 major environmental concerns:Soil erosionWater pollutionAir pollution
9 Soil Healthy soil supports both agriculture and forestry Topsoil – contains nutrients and minerals essential to growthCan be a renewable resource if managed properlySoil erosion – removal of soil by water and wind (over farming, over grazing…)
10 Soil erosionDesertification – turning farmland into dessert by over farming, over grazing, seasonal drought and climate changeDeforestation – loss of forests, trees hold soil in place
12 Soil Use and Sustainability Leave stems and roots in groundCrop rotationAltering the shape of the land- contour farming
13 Freshwater ResourcesFreshwater is usually a renewable resource but if not removed faster than can be replaced: nonrenewableAquifer: underground water reserve
14 Water pollutionHarmful materials that enter the biosphere and water sourcePoint source pollution: from single source like an oil spillNonpoint sources – pollution from smaller sources, such as oil and grease off streetsPrimary pollution sourcesAgricultural chemicals, residential sewage and nonpoint sources
15 Water quality and sustainability Watershed conservation – clean up pollutionSewage treatmentIPM – integrated pest management, instead of pesticides (ladybugs)Conserving water – drip irrigation
16 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
18 Acid RainSteps:Coal –burning power plants put smoke high into the atmosphereThe smoke contains high levels of sulfurThe smokestacks were to dissipate the smoke, backfiredSmoke combines with water vapor =sulfuric acidAcidified precipitation = ACID RAIN
22 Ozone Layer O3, protective shield in upper atmosphere Layer is thinning and disappearingAllows more UV rays into environmentWhy is this an issue?
23 Destruction of Ozone CFC’s – Chlorofluorocarbons Heat exchanger, refrigerator coolant, aerosol propellant, foaming agentsUV rays are strong enough to break the bonds in CFC’s, releasing chlorine atoms, which in turn react with ozone, destroying itLimit or ban use of CFC’sUS – limit CFC’s in aerosol’s
24 Ozone Depletion CFCs escape into amosphere CFCs destroy ozone More UV radiation reaches Earth’s surfaceSkin cancer cases increase
25 Good and Bad Ozone Good Bad (forms when sun and emissions react) Protective layer, absorbs UV raysBetween 11 – 16 miles above sea levelBad (forms when sun and emissions react)Corrosive, reactive gasPollutant at surface levelsIrritates and damages lungs and eyes, suppresses immune system