PROBLEM 3P
A power plant produces 1 GW of electricity, at an efficiency of 40% (typical of today’s coal-fired plants).
(a) At what rate does this plant expel waste heat into its environment?
(b) Assume first that the cold reservoir for this plant is a river whose flow rate is 100 m3/s. By how much will the temperature of the river increase?
(c) To avoid this “thermal pollution” of the river, the plant could instead be cooled by evaporation of river water. (This is more expensive, but in some areas it is environmentally preferable.) At what rate must the water evaporate? What fraction of the river must be evaporated?
SarahStewart BIOL1040 Exam3notes Chapter43:ReproductionandEmbryonicDevelopment Lecturegiven3/29/16 HumanReproduction: • Bothspeciesmusthaveasetofgonads,ductsforgametetransport,and structuresforcopulation MaleReproduction: • Testesproducespermandmalehormones • Epididymisstoresspermastheydevelop • Multipleglandscontributetosemen:theseminalvesicles,theprostategland, andthebulbourethralglands • Duringejaculation:spermisexpelledfromthepenis,glandssecreteintothe urethra,andsemenisformedandexpelled • Spermproductionisregulatedbyanegativefeedbacksystem • Involvesthehypothalamus,anteriorpituitary,andthetestes • Testesistheorganaffectedbythesehormones;producespermandandrogens (sexhormonesthatcauselowervoice)oncemalereachespuberty • LHistheluteinizinghormonethatactsuponthecellsinthetestes,andFSHisthe folliclestimulatinghormonethatmakesthetestesproducetestosterone;these twohormonescomefromthefemalereproductivesystem FemaleReproduction: • Meanttocarryapregnancy SarahStewart BIOL1040 Exam3notes • Hormonessynchronizecyclicchangesintheovaryanduterus,approximately every28days;canbesynchronizedwithotherfemales • Thiscycle’spurposeistoprepareawomenforapregnancy,greatvariation betweeneverywoman • ThehypothalamussignalstheanteriorpituitarytosecreteFSHandLH o LH–stimulatesgrowthoffollicle,promotesovulationanddevelopment ofcorpusluteum o FSH–stimulatesgrowthoffollicle • Triggerthegrowthofanovarianfollicleandovulation • Afterovulation,thefolliclebecomesthecorpusluteum • Thecorpusluteumsecretsestrogenandprogesteronewhich o Stimulatetheendometrium(uterinelining)tothicken o Preparetheuterusforimplantation o Inhibitthehypothalamus,whichreducesFSHandLH–negativefeedback loop • Onlyabout30%ofimplantationsaresuccesses,mostimportanttimeinthe reproductivecycle • Iftheeggisfertilized,embryoreleaseshormonesthatmaintaintheuterine lining:menstruationdoesnotoccur o Embryonicstageisthefirstthreemonthsofpregnancy SarahStewart BIOL1040 Exam3notes o Remaining2stagesarethefetaldevelopmentstage,embryobegins takingonhumancharacteristics • Iftheeggisnotfertilized,thedropinLHshutsdownthecorpusluteumandits hormones;menstruationistriggeredandthehypothalamusandpituitaryforma newfollicle–estrogen/progesteronenolongerinhibitingthis MenstrualCycle • Beginswithovulation;generallyoccursaroundday14 • LHandFHSlevelsspike,whichstimulatesthefollicletobereleasedandtogrow • Thefolliclegrowsandsecretesestrogen;oncethecorpusluteumisformedby thefollicle,itsecretesprogesteroneandestrogen • Estrogenandprogesteronepromotetherapidthickeningoftheuterinewall o Estrogen-lowlevelsinhibitpituitary,highlevelsstimulatehypothalamus o Progesterone–maintainendometrium,highlevelsinhibithypothalamus andpituitary–sharpdropspromotemenstruation • Iftheeggisnotfertilized,theliningissloughedoffandthisiswhatcauses menstrualbleeding Chapter45:PopulationandCommunityEcology Lecturegiven3/31/16 • Populationecologyisconcernedwithchangesinpopulationsizeandfactorsthat regulatepopulationsovertime,suchasimmigrationandemigration o Toomanypeopleonthisearthtomaintainasustainableenvironment SarahStewart BIOL1040 Exam3notes • Populationsincreasethroughbirthandimmigrationtoanareaanddecrease throughdeathandemigrationoutofanarea Population–agroupofindividualsofasinglespeciesthatoccupythesamegeneral area;fromareproductiveviewitisagroupofindividualsthatsharecommongenepool Populationdynamics–theinteractionsbetweenthebiotic(living)andabiotic(nonliving) factorscausesvariationinpopulationsizes • Individualsinapopulationrelyonthesameresources,areinfluencedbythe sameenvironmentalfactors,andarelikelytointeractandbreedwitheachother • Populationmaybedescribedbythenumberanddistributionofindividuals • 46.2millionlivinginpovertyintheUS(below$27,000)–mostresourcesare consumedbyrelativelyfewpeopleindevelopedcountries Populationdensity–thenumberofindividualsofaspeciesperunitareaorvolume;i.e. numberofoaktreespersquarekilometerinaforest • Ecologistsuseavarietyofsaplingtechniquestoestimatepopulationdensities, notalwayseasytodetermine • Animalsmovearoundanddensitiesvaryinapopulation’srange,soyoucantbe completelyconfidentinadensitynumber Capture-recapture–samplingmethodthatmakestheassumptionsthatmarkinghasno effectonmortality,markinghasnoeffectonthelikelihoodofbeingcaptured,andthat thereisnoimmigrationoremigrationbetweenthesamplingtimes SarahStewart BIOL1040 Exam3notes Dispersionpattern–thewayindividualsarespacedwithinanarea;canbeclumped, nearlyuniform,orrandom Lifehistorypattern–asetofadaptionsthatinfluencesurvival,fertility,andtheageat firstreproduction;asetofconditionspertainingtoanindividual’sscheduleof reproduction,summarizedinlifetables/survivorshipcurves • Lifetables o Trackage-specificpatterns o Populationdividedintoagecategories o Birthandmortalityratescalculatedforeachagecategory o Eachspecieshasacharacteristiclifespan,notallachieveit • Survivorshipcurves–usedtoplotacohort’sage-specificsurvivalinahabitat o TypeI–highsurvivorshipuntillateinlife,thenalargeincreaseindeath; elephants,humans o TypeII–reflectafairlyconstantdeathrateatallages;lizards,small mammals,largebirds o TypeIII–deathratehighestearlyon,speciesthatproducemanysmall offspringanddolittleparenting;invertebrates
