COASTS AND SHORES 1 The terms "coast" and "shore" are often used interchangeably, but there are actually differences between them. One difference is that "coast" applies only to oceans, but "shore" can apply to other bodies of water as well. A shore is the zone at the edge of an ocean, lake, or river that is subject to the regular action of tides, waves, and currents. The shore is the area between the high-water mark and the low-water mark, and thus every part of it is sometimes underwater. The shifting line where the shore meets the water is called the shoreline. An ocean shore extends seaward to the edge of the continental shelf--the submerged edge of the continental block--or to the beginning of the continental slope, which extends down into deep water. 2 A coast is the land just inland from the shore, beyond the usual reach of high water. On the shore side, the boundary of the coast--the coastline--may be either a cliff face or a line marking the inland limit of tidewater. On the landward side, the boundary is usually the edge of a highland or some other kind of terrain distinct from the shore; however, some coastal boundaries have no clear distinction. Many coasts are sea bottoms uplifted by earthquakes to become dry land, so they may show some features of shores, even though the sea never reaches them. 3 In areas where river valleys meet the sea along a rocky coast, bays are likely to occur. The direction of the structural "grain" of the coastal rock affects the shape of the coastline. If the grain is mostly parallel to the coast, as along the Oregon coast, the mouths of few rivers will indent the coastline because river valleys tend to follow the grain. Such coastlines--called Pacific type--are likely to be smooth, straight, or gently curving. On the other hand, if the grain of the rock is at an angle to the coast, as in Maine and Norway, many more valleys will reach the coastline, forming closely spaced bays. Such coastlines are of the Atlantic type. 4 Coasts and shores are areas of continuous change. Like all other terrain, coasts and shores are subject to the processes of weathering, erosion, deposition, and tectonic activity. Unlike other terrain, shores are also subject to the daily action of tides, waves, and currents. These forces erode rocky shores and transport sand and debris from place to place, depleting some beaches and building up others. During storms, waves crash against sea cliffs, weakening them and creating rockfalls and landslides. Storm waves batter beaches and--especially at high tide--rush beyond them, sweeping away docks, roads, and buildings. Over time, coastal processes change as tectonic activity raises, lowers, and disrupts the terrain and the sea bottoms near shores. Coastal processes are also affected by changes in sea level due to melting glaciers and changes in the density and temperature of ocean water.

Reading3"'BuildingwithArches"RoundArchandVault→AlthoughtheroundarchwasusedbytheancientpeoplesofMesopotamiaseveralcenturiesbeforeourcommonera,itwasmostfullydevelopedbytheRomans,whoperfectedtheforminthe2ndcenturyB.C.E.Thearchhasmanyvirtues.Inadditiontobeinganattractiveform,itenablesthearchitecttoopenupfairlylargespacesinawallwithoutriskingthebuilding'sstructuralsoundness.Thesespacesadmitlight,reducetheweightofthewalls,anddecreasetheamountofmaterialneeded.AsutilizedbytheRomans,thearchisaperfectsemicircle,althoughitmayseemelongatedifitrestsoncolumns.Itisconstructedfromwedge-shapedpiecesofstonethatmeetatananglealwaysperpendiculartothecurveofthearch.Becauseoftensionsandcompressionsinherentintheform,thearchisstableonlywhenitiscomplete,whenthetopmoststone,thekeystone,hasbeensetinplace.Forthisreasonanarchunderconstructionmustbesupportedfrombelow,usuallybyawoodenframework.→AmongthemostelegantandenduringofRomanstructuresbasedonthearchisthePontduGardatNimes,France,builtabout15C.E.whentheempirewasnearingitsfarthestexpansion.Atthistime,industry,commerce,andagriculturewereattheirpeak.Romanengineeringwasappliedtoanambitioussystemofpublic-worksprojects,notjustinItalybutintheoutlyingareasaswell.ThePontduGardfunctionedasanaqueduct,astructuremeanttotransportwater,anditslowerlevelservedasafootbridgeacrosstheriver.Thatitstandstodayvirtuallyintactafternearlytwothousandyears(andiscrossedbycyclistsontherouteofthefamousTourdeFrancebicyclerace)testifiestotheRomans'brilliantengineeringskills.Visually,thePontduGardexemplifiesthebestqualitiesofarchconstruction.Solidandheavy,obviouslydurable,itisshotthroughwithopenspacesthatmakeitseemlightanditsweight-bearingcapabilitieseffortless.→Whenthearchisextendedindepth—whenitis,inreality,manyarchesplacedflushonebehindtheother—theresultiscalledabarrelvault.Thisvaultconstructionmakesitpossibletocreatelargeinteriorspaces.TheRomansmadegreatuseofthebarrelvault,butforitsfinestexpressionwelookmanyhundredsofyearslater,tothechurchesoftheMiddleAges.→ThechurchofSainte-Foy,intheFrenchcityofConques,isanexampleofthestyleprevalentthroughoutWesternEuropefromabout1050to1200—astyleknownasRomanesque.RomanesquebuildersadoptedtheoldRomanformsofroundarchandbarrelvaultsoastoaddheighttotheirchurches.Untilthisperiodmostchurcheshadbeamedwoodenroofs,whichnotonlyposedathreatoffirebutalsolimitedtheheighttowhicharchitectscouldaspire.Withthestonebarrelvault,theycouldachievethesoaring,majesticspaceweseeinthenaveofSainte-Foy.PointedArchandVault→WhiletheroundarchandvaultoftheRomanesqueerasolvedmanyproblemsandmademanythingspossible,theyneverthelesshadcertaindrawbacks.Foronething,aroundarch,tobestable,mustbeasemicircle;therefore,theheightofthearchislimitedbyitswidth.Twootherdifficultieswereweightanddarkness.Barrelvaultsarebothliterallyandvisuallyheavy,callingforhugemassesofstonetomaintaintheirstructuralstability.Also,thebuilderswhoconstructedthemdarednotmakelight-admittingopeningsinoraroundthem,forfearthearchesandvaultswouldcollapse,andsotheinteriorsofRomanesquebuildingstendtobedark.TheGothicperiodinEurope,whichfollowedtheRomanesque,solvedtheseproblemswiththepointedarch.Thepointedarch,whileseeminglynotverydifferentfromtheroundone,offersmanyadvantages.Becausethesidesarcuptoapoint,weightischanneleddowntothegroundatasteeperangle,andthereforethearchcanbetaller.Thevaultconstructedfromsuchanarchalsocanbemuchtallerthanabarrelvault.ArchitectsoftheGothicperiodfoundtheydidnotneedheavymassesofmaterialthroughoutthecurveofthevault,aslongasthemajorpointsofintersectionwerereinforced.Glossarynave:thelongcentralareainachurchwithaislesoneachside

THEORIES OF EXPERIENCE AND EDUCATION 1 Two American philosophers, William James and John Dewey, developed very influential theories about how we think and learn. Both believed that the truth of any idea is a function of its usefulness and that experience is central to learning. 2 William James (1842-1910) was a philosopher and psychologist who believed that truth is not absolute and unchangeable; rather, it is made in actual, real-life events. In a person's life, there are experiences that have meaning and truth for that person. {{U}}Truth cannot be separated from experience, and in order to understand truth, we have to study experience itself.{{/U}} Thus, for James, human experience should be the primary subject of study, and he called upon thinkers to concentrate on experience instead of essences, abstractions, or universal laws. 3 James focused on what he called the "stream" of experience, the {{U}}sequential{{/U}} course of events in our lives. He believed that human consciousness is a stream of thoughts and feelings, and that this stream of consciousness is always going on, whether we are awake or asleep. The stream consists of very complex waves of bodily sensations, desires and aversions, memories of past experiences, and determinations of the will. One wave dissolves into another gradually, like the ripples of water in {{U}}a river.{{/U}} 4 In James's theory, thought and experience are connected. Incoming waves of thought flow in next to outgoing waves of previous experience and thus become associated with each other. An incoming thought is "{{U}}workable{{/U}}" only if it is meaningful and can be associated with something already in the person's mind. James's theory supports later theories of associative learning, which assert that new learning involves activating previous learning to find "hooks" on which to hang new information. 5 The theories of John Dewey (1859-1952), philosopher and educator, have had a tremendous impact on generations of thinkers. Dewey viewed life as a continuously {{U}}reconstructive{{/U}} process, with experience and knowledge building on each other. He believed that learning is more than the amassing and retention of information; learning is learning how to think. Thinking is not something abstract; it is a living process that starts when old habits meet new situations. 6 For Dewey, experience cannot be separated from nature because all experience is rooted in nature. Nature is what we experience: air, stones, plants, diseases, pleasure, and suffering. Dewey believed that experience is an interaction between what a person already knows and the person's present situation. Previous knowledge of nature interacts with the present environment, and together they lead to new knowledge that in turn will influence future experience. 7 Dewey asserted that experience is central to education; however, experience cannot be equated with education because all experiences are not necessarily educative. Experience is educative only when it contributes to the growth of the individual. It can be miseducative if it distorts the growth of further experience. It is the quality of experience that matters. Thus, productive experience is both the means and the goal of education. 8 Dewey felt that education should be problem-centered and interdisciplinary rather than subject-centered and fragmented. The methods and curricula of education must make the child's growth the central concern. Furthermore, truly progressive education must involve the participation of the learner in directing the learning experience.

Reading1"ExoticandEndangeredSpecies"→Whenyouhearsomeonebubblingenthusiasticallyaboutanexoticspecies,youcansafelybetthespeakerisn'tanecologist.Thisisanameforaresidentofanestablishedcommunitythatwasdeliberatelyoraccidentallymovedfromitshomerangeandbecameestablishedelsewhere.Unlikemostimports,whichcan'ttakeholdoutsidetheirhomerange,anexoticspeciespermanentlyinsinuatesitselfintoanewcommunity.Sometimestheadditionsareharmlessandevenhavebeneficialeffects.Moreoften,theymakenativespeciesendangeredspecies,whichbydefinitionareextremelyvulnerabletoextinction.Ofallspeciesontherareorendangeredlistsorthatrecentlybecameextinct,closeto70percentowetheirprecariousexistenceordemisetodisplacementbyexoticspecies.Twoexamplesareincludedheretoillustratetheproblem.Duringthe1800s,BritishsettlersinAustraliajustcouldn'tbondwiththekoalasandkangaroos,sotheystartedtoimportfamiliaranimalsfromtheirhomeland.In1859,inwhatwouldbethestartofawholesaledisaster,anorthernAustralianlandownerimportedandthenreleasedtwodozenwildEuropeanrabbits(Oryctolaguscuniculus).Goodfoodandgoodsporthunting—thatwastheidea.Anidealrabbithabitatwithnonaturalpredatorswasthereality.Sixyearslater,thelandownerhadkilled20,000rabbitsandwasbesiegedby20,000more.Therabbitsdisplacedlivestock,evenkangaroos.NowAustraliahas200to300millionhippityhoppingthroughthesouthernhalfofthecountry.Theyovergrazeperennialgrassesingoodtimesandstripbarkfromshrubsandtreesduringdroughts.Youknowwherethey'vebeen;theytransformgrasslandsandshrublandsintoerodeddeserts.Theyhavebeenshotandpoisoned.Theirwarrenshavebeenplowedunder,fumigated,anddynamited.Evenwhenall-outassaultsreducedtheirpopulationsizeby70percent,therapidlyreproducingimportsmadeacomebackinlessthanayear.Didtheconstructionofa2,000-mile-longfenceprotectwesternAustralia?No.Rabbitsmadeittotheothersidebeforeworkersfinishedthefence.→In1951,governmentworkersintroducedamyxomavirusbywayofmildlyinfectedSouthAmericanrabbits,itsnormalhosts.Thisviruscausesmyxomatosis.ThediseasehasmildeffectsonSouthAmericanrabbitsthatcoevolvedwiththevirusbutnearlyalwayshadlethaleffectsonO.cuniculus.Bitinginsects,mainlymosquitoesandfleas,quicklytransmitthevirusfromhosttohost.Havingnocoevolveddefensesagainstthenovelvirus,theEuropeanrabbitsdiedindroves.But,asyoumightexpect,naturalselectionhassincefavoredrapidgrowthofpopulationsofO.cuniculusresistanttothevirus.→In1991,onanuninhabitedislandinSpencerGulf,Australianresearchersreleasedapopulationofrabbitsthattheyhadinjectedwithacalcivirus.Therabbitsdiedquicklyandrelativelypainlesslyfrombloodclotsintheirlungs,hearts,andkidneys.In1995,thetestvirusescapedfromtheisland,possiblyoninsectvectors.Ithasbeenkilling80to95percentoftheadultrabbitsinAustralianregions.Atthiswriting,researchersarenowquestioningwhetherthecalcivirusshouldbeusedonawidespreadscale,whetheritcanjumpboundariesandinfectanimalsotherthanrabbits(suchashumans);andwhatthelong-termconsequenceswillbe.Avinecalledkudzu(Puerarialobata)wasdeliberatelyimportedfromJapantotheUnitedStates,whereitfacesnoseriousthreatsfromherbivores,pathogens,orcompetitorplants.IntemperatepartsofAsia,itisawell-behavedlegumewithawell-developedrootsystem.ItseemedlikeagoodideatouseittocontrolerosiononhillsandhighwayembankmentsinthesoutheasternUnitedStates.Withnothingtostopit,though,kudzu'sshootsgrewathirdofameterperday.Vinesnowblanketstreambanks,trees,telephonepoles,houses,andalmosteverythingelseintheirpath.Attemptstodiguporburnkudzuarefutile.Grazinggoatsandherbicideshelp,butgoatseatotherplants,too,andherbicidescontaminatewatersupplies.KudzucouldreachtheGreatLakesbytheyear2040.→Onthebrightside,aJapanesefirmisconstructingakudzufarmandprocessingplantinAlabama.TheideaistoexportthestarchtoAsia,wherethedemandcurrentlyexceedsthesupply.Also,kudzumayeventuallyhelpreduceloggingoperations.AttheGeorgiaInstituteofTechnology,researchersreportthatkudzumightbecomeanalternativesourceforpaper.

THE UNDERGROUND RAILROAD 1 Slavery was legal for over 200 years in some parts of North America, particularly the southern states of the United States, where the plantation system of agriculture depended on the labor of slaves, most of whom came from Africa. Slaves had no rights or freedoms because they were thought of as property. From the time of its origin, slavery had opponents. The abolitionist movement began in the 1600s when the Quakers in Pennsylvania objected to slavery on moral grounds and wanted to {{U}}abolish{{/U}} the institution. 2 In 1793, Canada passed a law abolishing slavery and declared that any escaped slaves who came to Canada would be free citizens. Slavery was already illegal in most northern states; however, slaves captured there by slave hunters could be returned to slavery in the South. Canada refused to return runaway slaves or to allow American slave hunters into the country. It is estimated that more than 30,000 runaway slaves immigrated to Canada and settled in the Great Lakes region between 1830 and 1865. 3 The American antislavery movement was at the height of its activity during the 1800s, when abolitionists developed the Underground Railroad, a loosely organized system whereby runaway slaves were passed from safe house to safe house as they fled northwards to free states or Canada. The term was first used in the 1830s and came from an Ohio clergyman who said, "They who took passage on it disappeared from public view as if they had really gone to ground." {{U}}Because the Underground Railroad was so secret, few records exist that would reveal the true number of people who traveled it to freedom.{{/U}} The most active routes on the railroad were in Ohio, Indiana, and western Pennsylvania. 4 Runaway slaves usually traveled alone or in small groups. Most were young men between the ages of 16 and 35. The {{U}}fugitives{{/U}} hid in wagons under loads of hay or potatoes, or in furniture and boxes in steamers and on rafts. They traveled on foot through swamps and woods, moving only a few miles each night, using the North Star as a compass. Sometimes they moved in broad daylight. Boys disguised themselves as girls, and girls dressed as boys. In one welt-known incident, twenty-eight slaves escaped by walking in a funeral procession from Kentucky to Ohio. 5 The "railroad" developed its own language. The "trains" were the large farm wagons that could conceal and carry a number of people. The "tracks" were the backcountry roads that were used to {{U}}elude{{/U}} the slave hunters. The "stations" were the homes and hiding places where the slaves were fed and cared for as they moved north. The "agents" were the people who planned the escape routes. The "conductors" were the fearless men and women who led the slaves toward freedom. The "passengers" were the slaves who dared to run away and {{U}}break for{{/U}} liberty. Passengers paid no fare and conductors received no pay. 6 The most daring conductor was Harriet Tubman, a former slave who dedicated her life to helping other runaways. Tubman made 19 trips into the South to guide 300 relatives, friends, and strangers to freedom. {{U}}She was wanted dead or alive in the South{{/U}}, but she was never captured and never lost a passenger. A determined worker, she carried a gun for protection and a supply of drugs to quiet the crying babies in her rescue parties. 7 A number of white people joined the effort, including Indiana banker Levi Coffin and his wife Catherine, who hid runaways in their home, a "station" conveniently located on three main escape routes to Canada. People could be hidden there for several weeks, recovering their strength and waiting until it was safe to continue on their journey. Levi Coffin was called the "president of the Underground Railroad" because he helped as many as 3,000 slaves to escape. The people who worked on the railroad were breaking the law. Although the escape network was never as successful or as well organized as Southerners thought, the few thousand slaves who made their way to freedom in this way each year had a symbolic significance out of proportion to their actual numbers. The Underground Railroad continued operating until slavery in the United States was finally abolished in 1865.

{{B}}Set5{{/B}}{{B}}Temperature{{/B}}Threescalesoftemperature,eachofwhichpermitsaprecisemeasurement,areinconcurrentuse:theFahrenheit,Celsius,andKelvinscales.Thesethreedifferenttemperaturescaleswereeachdevelopedbydifferentpeopleandhavecometobeusedindifferentsituations.ThescalethatismostwidelyusedbythegeneralpublicintheUnitedStatesistheFahrenheitscale.In1714,DanielGabrielFahrenheit,aGermanphysicistwhowaslivinginHollandandoperatinganinstrumentbusiness,developedamercury-in-glassthermometerandthetemperaturescalethatstillcarrieshisname.Hisoriginalscalehadtwofixedpoints:0°wasthelowesttemperaturethathecouldachieveinasolutionofice,water,andsalt,and96°waswhathebelievedwasthenormaltemperatureofthehumanbody(thoughthiswaslaterdeterminedtobe98.6°).Basedonthisscale,hecalculatedthatthefreezingpoint(oricepoint)ofwaterwas32°;inlaterstudies,itwasdeterminedthattheboilingpointofwater(thesteampoint)was212°.TheFahrenheitscalecametobeacceptedasthestandardmeasureoftemperatureinanumberofcountries,includingGreatBritain,andfromthereitwasspreadtoBritishcoloniesthroughouttheworld.Today,however,theUnitedStatesistheonlymajorcountryintheworldthatstillusestheFahrenheitscale.ThescalethatisinuseinmanyothercountriesistheCelsiusscale.AndersCelsius(1701～1744),aSwedishastronomer,developedathermometerin1741thatbasedtemperaturesonthefreezingandboilingtemperaturesofwater.OnthethermometerthatCelsiusdeveloped,however,0°wasusedtoindicatetheboilingtemperatureofwater,and100°wasusedtoindicatethefreezingtemperatureofwater.Afterhisdeath,thescalewasreversedbyafriend,thebiologistCarlvonLinne(1707～1748),whoachievedacclaimforhisdevelopmentoftheLinneanclassificationsystemforplantsandanimals.OnthenewscaleafterthereversalbyvonLinne,0°indicatedthefreezingtemperatureofwater,and100°indicatedtheboilingtemperatureofwater.AtaroundthesametimethatCelsiusandvonLinnewereworkingontheirthermometerinSweden,asimilarthermometerwasbeingdevelopedinFrance.AftertheFrenchRevolution,thescaledevelopedinFrancewasadoptedaspartofthemetricsysteminthatcountryunderthenamecentigrade,whichmeans"ahundredunits,"andfromthereitspreadworldwide.In1948,aninternationalagreementwasmadetorenamethecentigradescaletheCelsiusscaleinhonorofthescientistwhowasfirstknowntousea100-degreescale,thoughitshouldberememberedthatthescalethatCelsiusactuallyusedhimselfwasthereverseoftoday'sscale.Athirdscale,theKelvinscale,isgenerallyusedtodayforscientificpurposes.Thisscalewasfirstsuggestedin1854bytwoEnglishphysicists:WilliamThomson,LordKelvin(1824～1907)andJamesPrescottJoule(1818～1889).TheKelvinscaledefines0°asabsolutezero,thehypotheticaltemperatureatwhichallatomicandmolecularmotiontheoreticallystops,and100°separatesthefreezingpointandboilingpointofwater,justasitdoesontheCelsiusscale.OntheKelvinscale,with0°equaltoabsolutezero,waterfreezesat273°,andwaterboilsatatemperature100°higher.TheKelvinscaleiswellsuitedtosomeareasofscientificstudybecauseitdoesnothaveanynegativevalues,yetitstillmaintainsthe100°differencebetweenthefreezingpointandboilingpointofwaterthattheCelsiusscalehasandcanthuseasilybeconvertedtotheCelsiusscalebymerelysubtracting273°fromthetemperatureontheKelvinscale.

Directions: Read the passage. Then answer the questions. Give yourself 20 minutes to complete this practice set. INFANTILE AMNESIA What do you remember about your life before you were three? Few people can remember anything that happened to them in their early years. Adults' memories of the next few years also tend to be scanty. Most people remember only a few events—usually ones that were meaningful and distinctive, such as being hospitalized or a sibling's birth. How might this inability to recall early experiences be explained? The sheer passage of time does not account for it; adults have excellent recognition of pictures of people who attended high school with them 35 years earlier. Another seemingly plausible explanation—that infants do not form enduring memories at this point in development—also is incorrect. Children two and a half to three years old remember experiences that occurred in their first year, and eleven month olds remember some events a year later. Nor does the hypothesis that infantile amnesia reflects repression—or holding back—of sexually charged episodes explain the phenomenon. While such repression may occur, people cannot remember ordinary events from the infant and toddler periods, either. Three other explanations seem more promising. One involves physiological changes relevant to memory. Maturation of the frontal lobes of the brain continues throughout early childhood, and this part of the brain may be critical for remembering particular episodes in ways that can be retrieved later. Demonstrations of infants' and toddlers' long-term memory have involved their repeating motor activities that they had seen or done earlier, such as reaching in the dark for objects, putting a bottle in a doll's mouth, or pulling apart two pieces of a toy. The brain's level of physiological maturation may support these types of memories, but not ones requiring explicit verbal descriptions. A second explanation involves the influence of the social world on children's language use. Hearing and telling stories about events may help children store information in ways that will endure into later childhood and adulthood. Through hearing stories with a clear beginning, middle, and ending, children may learn to extract the gist of events in ways that they will be able to describe many years later. Consistent with this view, parents and children increasingly engage in discussions of past events when children are about three years old. However, hearing such stories is not sufficient for younger children to form enduring memories. Telling such stories to two year olds does not seem to produce long-lasting verbalizable memories. A third likely explanation for infantile amnesia involves incompatibilities between the ways in which infants encode information and the ways in which older children and adults retrieve it. Whether people can remember an event depends critically on the fit between the way in which they earlier encoded the information and the way in which they later attempt to retrieve it. The better able the person is to reconstruct the perspective from which the material was encoded, the more likely that recall will be successful. This view is supported by a variety of factors that can create mismatches between very young children's encoding and older children's and adults' retrieval efforts. The world looks very different to a person whose head is only two or three feet above the ground than to one whose head is five or six feet above it. Older children and adults often try to retrieve the names of things they saw, but infants would not have encoded the information verbally. General knowledge of categories of events such as a birthday party or a visit to the doctor's office helps older individuals encode their experiences, but again, infants and toddlers are unlikely to encode many experiences within such knowledge structures. These three explanations of infantile amnesia are not mutually exclusive; indeed, they support each other. Physiological immaturity may be part of why infants and toddlers do not form extremely enduring memories, even when they hear stories that promote such remembering in preschoolers. Hearing the stories may lead preschoolers to encode aspects of events that allow them to form memories they can access as adults. Conversely, improved encoding of what they hear may help them better understand and remember stories and thus make the stories more useful for remem bering future events. Thus, all three explanations—physiological maturation, hearing and producing stories about past events, and improved encoding of key aspects of events—seem likely to be involved in overcoming infantile amnesia. encode: transfer information from one system of communication into another

THE PRODUCTION OF COFFEE 1 All great coffee comes from the same tree, Coffea arabica. The distinguishing taste of coffee is a product of the climate, air, and soil in which it is grown. The perfect climate for coffee production exists between the latitudes of 25 degrees north and 25 degrees south of the equator. The coffee plant is particular about temperature, and changes of more than 20 degrees in twenty-four hours, or temperatures of over 70 degrees Fahrenheit, tend to have harmful effects on production. In general, coffee trees are comfortable where people are. If people feel too cold or hot, especially during flowering and fruit development, the trees are not likely to do well. 2 Altitude is an important factor, and most coffee-producing countries grade their coffees according to the altitude at which they were grown. The best-tasting coffees are grown at between five and eight thousand feet in elevation, in the thin air and rocky soil of places such as the mountain ridges of Central America and Africa. 3 Coffee trees require certain nutrients to produce beans in economically viable quantities; thus, soil chemistry is carefully watched in commercial operations. A soil rich in nitrogen, phosphorus, and potassium will yield a coffee more complex in character. Nitrogen in soil gives rise to coffee's sparkling acidity; potassium produces fuller-bodied coffees; and phosphorus, while having no bearing on coffee in the final cup, helps the tree to develop a healthy root system. Generally, the more balanced the soil, the better the coffee. 4 Caring for the coffee tree is critical to the character of the final product. Stock for new coffee trees is usually grown from seeds produced by trees already growing on the farm. After the seeds germinate, the seedlings are transferred to nursery beds, which are typically kept under mesh netting that filters out direct sunlight. Young seedlings grow slowly, are very delicate, and require careful replanting. The transfer from nursery to plantation is a critical part of the process, and a seedling that is mishandled at this stage may die after it is replanted. Most varieties take at least three years before they begin producing fruit.

{{B}}Set 2 Geology plate Tectonics{{/B}}

HE GREENHOUSE EFFECT 1 In the nineteenth century, scientists discovered that certain gases in Earth"s atmosphere behave like the panes of glass in a greenhouse. These gases admit visible radiation from the sun but prevent the escape of infrared radiation from Earth"s surface. Because of their radiative properties, the action of these atmospheric gases is known as the greenhouse effect, and the gases are known as greenhouse gases. Water vapor is the principal greenhouse gas. Others are carbon dioxide, ozone, methane, and nitrous oxide. 2 Window glass is relatively transparent to visible radiation but slows the transmission of infrared radiation. Plant greenhouses are designed to take advantage of this property of glass by being constructed almost entirely of glass panes. Visible radiation--light from the sun-- enters the greenhouse, and is absorbed by the dark plants. Thus, light energy is converted to heat. The plants use some of the heat and re-radiate the rest as infrared radiation, most of which cannot escape the greenhouse because it is trapped by the solid glass. The atmosphere inside the greenhouse therefore becomes heated, and the temperature can rise well above that of the outside air. Similarly, greenhouse gases in Earth"s atmosphere keep infrared radiation from escaping into space, thereby keeping the planet warm. 3 However, the greenhouse analogy is not completely accurate because the trapping of infrared radiation by glass is only part of the reason that most plant greenhouses retain internal heat . Greenhouses cut heat loss mainly by acting as a shelter from the wind, thereby reducing heat loss due to conduction and convection . As a rule, the thinner the greenhouse glass and the stronger the external wind speed, the more important the shelter effect is. Still, the greenhouse analogy remains relevant in most discussions of radiation balance in Earth"s atmospheric system. 4 The effect of a greenhouse gas can be seen by comparing the typical summer weather of the American Southwest with that of the coast along the Gulf of Mexico. Both areas are at about the same latitude and therefore receive about the same intensity of solar radiation. In both places, afternoon temperatures typically exceed 30 degrees Celsius. At night, however, air temperatures often differ remarkably due to the absence or presence of the leading greenhouse gas, water vapor. In the desert Southwest, there is less water vapor in the air to impede the escape of infrared radiation; therefore, heat is readily lost to space. Air temperatures on the surface of the Southwest desert may fall below 15 degrees Celsius. In contrast, along the more humid Gulf Coast, infrared radiation does not escape to space as readily, and minimum temperatures may fall only into the 20s Celsius. 5 Clouds produce a greenhouse effect because they are composed of radiation-absorbing water droplets or ice crystals. Nights are usually warmer when the sky is cloud-covered than when the sky is clear. However, clouds can affect climate in two opposing ways. On the one hand, clouds warm the planet"s surface by absorbing and re-radiating infrared radiation; on the other hand, they cool the surface by reflecting solar radiation away from Earth. Analyses of satellite measurements of radiation indicate that clouds have a net cooling effect on global climate. Thus, a more extensive cloud cover would tend to cool the planet. 6 The greenhouse effect also operates on other planets. On both Mars and Venus, the principal atmospheric gas, carbon dioxide, is also the main greenhouse gas. Earth has an abundance of plants to absorb carbon dioxide, but Mars and Venus do not possess living organisms. Consequently, Earth"s two closest neighbors have extremely high concentrations of atmospheric carbon dioxide. The atmosphere of Mars is considerably thinner than the atmosphere on Earth, so its greenhouse effect raises the average surface temperature by only about 10 degrees Celsius. In contrast, the atmosphere of Venus is about 90 times denser than Earth"s, and its greenhouse warming is estimated at 523 degrees Celsius. The hot, thick, cloud-filled atmosphere shrouding Venus is composed of 97 percent carbon dioxide. Some scientists believe that Venus used to be similar to Earth, with liquid water on the surface. Then, billions of years ago, Venus started to heat up. Eventually, all its surface water evaporated into the atmosphere, and planetary warming became self-sustaining and unstoppable. Venus provides a warning for what could happen on Earth if the greenhouse effect continued unchecked and a high percentage of surface water became water vapor. If that happened, global warming would reach the point of no return , as it did on Venus.

GeothermalEnergyGeothermalenergyisnaturalheatfromtheinterioroftheEarththatisconvertedtoheatbuildingsandgenerateelectricity.TheideaofharnessingEarth'sinternalheatisnotnew.Asearlyas1904,geothermalpowerwasusedinItaly.Today,Earth'snaturalinternalheatisbeingusedtogenerateelectricityin21countries,includingRussia,Japan,NewZealand,Iceland,Mexico,Ethiopia,Guatemala,E1Salvador,thePhilippines,andtheUnitedStates.Totalworldwideproductionisapproaching9,000MW(equivalenttoninelargemoderncoal-burningornuclearpowerplants)--doubletheamountin1980.Some40millionpeopletodayreceivetheirelectricityfromgeothermalenergyatacostcompetitivewiththatofotherenergysources.InE1Salvador,geothermalenergyissupplying30%ofthetotalelectricenergyused.However,atthegloballevel,geothermalenergysupplieslessthan0.15%ofthetotalenergysupply.Geothermalenergymaybeconsideredanonrenewableenergysourcewhenratesofextractionaregreaterthanratesofnaturalreplenishment.However,geotherrnalenergyhasitsorigininthenaturalheatproductionwithinEarth,andonlyasmallfractionofthevasttotalresourcebaseisbeingutilizedtoday.Althoughmostgeothermalenergyproductioninvolvesthetappingofhighheatsources,peoplearealsousingthelow-temperaturegeothermalenergyofgroundwaterinsomeapplications.GeothermalSystemsTheaverageheatflowfromtheinterioroftheEarthisverylow,about0.06W/m2.Thisamountistrivialcomparedwiththe177W/m2fromsolarheatatthesurfaceintheUnitedStates.However,insomeareas,heatflowissufficientlyhightobeusefulforproducingenergy.Forthemostpart,areasofhighheatflowareassociatedwithplatetectonicboundaries.Oceanicridgesystems(divergentplateboundaries)andareaswheremountainsarebeingupliftedandvolcanicislandarcsareforming(convergentplateboundariesareareaswherethisnaturalheatflowisanomalouslyhigh.Onthebasisofgeologicalcriteria,severaltypesofhotgeothermalsystems(withtemperaturesgreaterthanabout80℃,or176℉)havebeendefined,andtheresourcebaseislargerthanthatoffossilfuelsandnuclearenergycombined.Acommonsystemforenergydevelopmentishydrothermalconvection,characterizedbythecirculationofsteamand/orhotwaterthattransfersheatfromdepthstothesurface.GeothermalEnergyandtheEnvironmentTheenvironmentalimpactofgeothermalenergymaynotbeasextensiveasthatofothersourcesofenergy,butitcanbeconsiderable.Whengeothermalenergyisdevelopedataparticularsite,environmentalproblemsincludeon-sitenoise,emissionsofgas,anddisturbanceofthelandatdrillingsites,disposalsites,roadsandpipelines,andpowerplants.Developmentofgeothermalenergydoesnotrequirelarge-scaletransportationofrawmaterialsorrefiningofchemicals,asdevelopmentoffossilfuelsdoes.Furthermore,geothermalenergydoesnotproducetheatmosphericpollutantsassociatedwithburningfossilfuelsortheradioactivewasteassociatedwithnuclearenergy.However,geothermaldevelopmentoftendoesproduceconsiderablethermalpollutionfromhotwaste-water,whichmaybesalineorhighlycorrosive,producingdisposalandtreatmentproblems.Geothermalpowerisnotverypopularinsomelocationsamongsomepeople.Forinstance,geothermalenergyhasbeenproducedforyearsontheislandofHawaii,whereactivevolcanicprocessesprovideabundantnear-surfaceheat.Thereiscontroversy,however,overfurtherexplorationanddevelopment.NativeHawaiiansandothershavearguedthattheexplorationanddevelopmentofgeothermalenergydegradethetropicalforestasdevelopersconstructroads,buildfacilities,anddrillwells.Inaddition,religiousandculturalissuesinHawaiirelatetotheuseofgeothermalenergy.Forexample,somepeopleareoffendedbyusingthe"breathandwaterofPele"(thevolcanogoddess)tomakeelectricity.Thisissuepointsouttheimportanceofbeingsensitivetothevaluesandculturesofpeoplewheredevelopmentisplanned.FutureofGeothermalEnergyAtpresent,geothermalenergysuppliesonlyasmallfractionoftheelectricalenergyproducedintheUnitedStates.However,ifdeveloped,knowngeothermalresourcesintheUnitedStatescouldproduceabout20,000MWwhichisabout10%oftheelectricityneededforthewesternstates.Geothermalresourcesnotyetdiscoveredcouldconservativelyprovidefourtimesthatamount(approximately10%oftotalU.S.electriccapacity),aboutequivalenttotheelectricityproducedfromwaterpowertoday.

ReadingⅠ"SymbioticRelationships"Symbiosisisaclose,long-lastingphysicalrelationshipbetweentwodifferentspecies.Inotherwords,thetwospeciesareusuallyinphysicalcontactandatleastoneofthemderivessomesortofbenefitfromthiscontact.Therearethreedifferentcategoriesofsymbioticrelationships:parasitism,commensalism,andmutualism.Parasitismisarelationshipinwhichoneorganism,knownastheparasite,livesinoronanotherorganism,knownasthehost,fromwhichitderivesnourishment.Generally,theparasiteismuchsmallerthanthehost.Althoughthehostisharmedbytheinteraction,itisgenerallynotkilledimmediatelybytheparasite,andsomehostindividualsmaylivealongtimeandberelativelylittleaffectedbytheirparasites.Someparasitesaremuchmoredestructivethanothers,however.{{U}}Newlyestablishedparasite/hostrelationshipsarelikelytobe{{/U}}{{U}}moredestructivethanthosethathavealongevolutionaryhistory.{{/U}}Withalongstandinginteractionbetweentheparasiteandthehost,thetwospeciesgenerallyevolveinsuchawaythattheycanaccommodateoneanother.Itisnotintheparasite'sbestinteresttokillitshost.Ifitdoes,itmustfindanother.Likewise,thehostevolvesdefensesagainsttheparasite,oftenreducingtheharmdonebytheparasitetoalevelthehostcan{{U}}tolerate.{{/U}}→Parasitesthatliveonthesurfaceoftheirhostsareknownas{{U}}ectoparasites.{{/U}}Fleas,lice,andsomemoldsandmildewsareexamplesofectoparasites.Manyotherparasites,liketapeworms,malariaparasites,manykindsofbacteria,andsomefungi,arecalled{{U}}endoparasites{{/U}}becausetheyliveinsidethebodiesoftheirhosts.Atapewormlivesintheintestinesofitshostwhereitisabletoresistbeingdigestedandmakesuseofthenutrientsintheintestine.Evenplantscanbeparasites.Mistletoeisafloweringplantthatisparasiticontrees.Itestablishesitselfonthesurfaceofatreewhenabirdtransferstheseedtothetree.Itthengrowsdownintothewater-conductingtissuesofthetreeandusesthewaterandmineralsitobtainsfromthesetissuestosupportitsowngrowth.Iftherelationshipbetweenorganismsisoneinwhichoneorganismbenefitswhiletheotherisnotaffected,itiscalledcommensalism.Itispossibletovisualizeaparasiticrelationshipevolvingintoacommensalone.Sinceparasitesgenerallyevolvetodoaslittleharmtotheirhostaspossibleandthehostiscombatingthenegativeeffectsoftheparasite,theymighteventuallyevolvetothepointwherethehostisnotharmedatall.Therearemanyexamplesofcommensalrelationships.Orchidsoftenusetreesasasurfaceuponwhichtogrow.Thetreeisnotharmedorhelped,buttheorchidneedsasurfaceuponwhichtoestablishitselfandalsobenefitsbybeingclosetothetopofthetree,whereitcangetmoresunlightandrain.Somemosses,ferns,andmanyvinesalsomakeuseofthesurfacesoftreesinthisway.Intheocean,manysharkshaveasmallerfishknownasaremoraattachedtothem.Remorashavea{{U}}sucker{{/U}}onthetopoftheirheadsthattheycanusetoattachtotheshark.Inthisway,theycanhitchhikearideasthesharkswimsalong.Whenthesharkfeeds,theremorafreesitselfandobtainssmallbitsoffoodthatthesharkmisses.Then,theremorareattaches.Thesharkdoesnotappeartobepositivelyornegativelyaffectedbyremoras.→Mutualismisanotherkindofsymbioticrelationshipandisactuallybeneficialtobothspeciesinvolved.Inmanymutualisticrelationships,therelationshipisobligatory;thespeciescannotlivewithouteachother.Inothers,thespeciescanexistseparatelybutaremoresuccessfulwhentheyareinvolvedinamutualisticrelationship.SomespeciesofAcacia,athornytree,providefoodintheformofsugarsolutionsinlittlestructuresontheirstems.Certainspeciesofantsfeedonthesolutionsandliveinthetree,whichtheywillprotectfromotheranimalsbyattackinganyanimalthatbeginstofeedonthetree.Bothorganismsbenefit;theantsreceivefoodandaplacetolive,andthetreeisprotectedfromanimalsthatwoulduseitasfood.→Onesoilnutrientthatisusuallyalimitingfactorforplantgrowthisnitrogen.Manykindsofplants,suchasbeans,clover,andaldertrees,havebacteriathatliveintheirrootsinlittle{{U}}nodules.{{/U}}Therootsformthesenoduleswhentheyareinfectedwithcertainkindsofbacteria.Thebacteriadonotcausediseasebutprovidetheplantswithnitrogen-containingmoleculesthattheplantscanuseforgrowth.Thenitrogen-fixingbacteriafromthelivingsiteandnutrientsthattheplantsprovide,andtheplantsbenefitfromthenitrogentheyreceive.Glossarysucker:anadaptationforsuckingnourishmentorstickingtoasurfacenodules:growthsintheformofknots