Environmental Problems, Their Causes, and Sustainability 1

Figure 4-9 Solar capital: flow of energy to andfrom the earth.SolarradiationEnergy in = Energy outReflected byatmosphere (34%)UV radiationAbsorbedby ozoneAbsorbedby theearthVisiblelightRadiated byatmosphereas heat (66%)Lower Stratosphere(ozone layer)GreenhouseTroposphere effectHeatEarthure 4-9. About 80% of the energy that gets throughwarms the troposphere and evaporates and cycles waterthrough the biosphere. About 1% of this incomingenergy generates winds, and green plants, algae, andbacteria use less than 0.1% to fuel photosynthesis.Most of the solar radiation making it though the atmospherehits the surface of the earth and is degradedinto longer-wavelength infrared radiation. This infraredradiation interacts with so-called greenhouse gases(such as water vapor, carbon dioxide, methane, nitrousoxide, and ozone) in the troposphere. The radiationcauses these gaseous molecules to vibrate and releaseinfrared radiation with even longer wavelengths intothe troposphere. As this radiation interacts with moleculesin the air, it increases their kinetic energy, helpingwarm the troposphere and the earth’s surface. Withoutthis natural greenhouse effect, the earth would be toocold for life as we know it to exist and you would not bearound to read this book.Heat radiatedby the earthViewed from outer space, the earth resemblesan enormous jigsaw puzzle consistingof large masses of land and vastexpanses of ocean.Biologists have classified the terrestrial(land) portion of the biosphere intobiomes (“BY-ohms”). They are large regionssuch as forests, deserts, and grasslandscharacterized by a distinct climateand specific species (especially vegetation)adapted to it (Figure 4-10, p. 62).Scientists divide the watery parts ofthe biosphere into aquatic life zones, eachcontaining numerous ecosystems. Examples includefreshwater life zones (such as lakes and streams) andocean or marine life zones (such as coral reefs, coastal estuaries,and the deep ocean).What Are the Major Componentsof Ecosystems? Matter, Energy, LifeEcosystems consist of nonliving (abiotic) and living(biotic) components.Two types of components make up the biosphere andits ecosystems. One type, called abiotic, consists ofnonliving components such as water, air, nutrients,and solar energy. The other type, called biotic, consistsof biological components—plants, animals, andmicrobes.Figures 4-11 (p. 63) and 4-12 (p. 63) are greatlysimplified diagrams of some of the biotic and abioticcomponents in a freshwater aquatic ecosystem and aterrestrial ecosystem.4-3 ECOSYSTEM COMPONENTSWhat Are Biomes and Aquatic Life Zones? Lifeon Land and at SeaLife exists on land systems called biomes and infreshwater and ocean aquatic life zones.How Tolerant Are Organisms toEnvironmental Conditions? ToleranceLimitsPopulations of different species can thrive onlyunder certain physical and chemical conditions.Populations of different species thrive under differentphysical conditions. Some need bright sunlight, andhttp://biology.brookscole.com/miller1461