Midterm 3, 2013

Key!!

1.!!There!are!many!methods!of!determining!the!fundamental!unit!of!a!population!6!N.!!The!choice!selected!by!a!population!ecologist!depends!on!the!behavior,!distribution!and!abundance!of!the!species.!!Dr.!Tim!Warner!in!Geography!has!devised!a!protocol!for!image!processing!satellite!photos!of!Monongalia!County!to!make!every!mature!flowering!chestnut!tree!stand!out!in!the!image.!!Assuming!these!trees!are!now!very!rare!(N!is!estimated!to!be!<100!for!the!county),!how!would!you!suggest!he!go!about!determining!N!from!the!imagery?!!A.##Direct#counts#B.!!Quadrat!sampling!C.!!Mark6Recapture!D.!!Survey!E.!!Stratified!random!!2.!!The!flat6spired!three6toothed!snail!is!a!rare!species!endemic!to!the!Cheat!Canyon!outside!of!Morgantown.!!On!a!particular!rock!outcrop,!it!is!difficult!to!know!N!precisely!because!the!snails!move,!and!some!of!them!are!out!of!sight,!though!populations!are!small!to!intermediate!in!size.!!What!technique!would!you!recommend!for!determining!N?!!A.!!Direct!counts!B.!!Quadrat!sampling!C.##Mark2Recapture#D.!!Survey!E.!!Stratified!random!!3.!!Regardless!of!how!you!answered!the!question!above,!a!technician!hired!by!Cooper's!Rock!State!Forest!decides!to!try!to!determine!N!by!marking!45!snails!she!found!with!a!small!dot!of!white!paint!on!the!shell.!!She!releases!those!snails!after!marking!them,!and!returns!one!week!later!to!perform!a!recapture.!!Of!the!96!snails!captured!at!the!second!time,!she!finds!only!12!have!her!white!dot!on!them.!!What!is!her!estimate!of!N!for!the!snails?!!A.!!5.65!B.!!25.6!C.!!253!D.##360#E.!!Cannot!be!estimated!from!the!information!given!! !

!4.!!Jessica!Turner,!a!biology!graduate!student,!is!studying!the!presence!of!'indicator!species'!for!good!American!ginseng!planting!sites.!!She!censuses!circular!4!m!diameter!quadrats!at!a!ginseng!site,!counting!the!number!of!indicator!plants!within!each!quadrat.!!She!wants!to!know!whether!these!plants!are!distributed!evenly,!randomly,!or!clumpily!(!)!across!the!forest!floor.!!She!calculates!a!mean!per!quadrat!of!7.5!indicator!plants,!and!a!variance!among!quadrats!of!18.6.!!What!can!she!conclude!about!the!dispersion!pattern!of!indicator!plants?!!A.!!Their!dispersion!is!uniform!(even)!B.!!Their!dispersion!is!random!C.##Their#dispersion#is#clumped#D.!!Their!dispersion!is!leptokurtic!E.!!!She!would!need!to!have!replicate!sites!to!determine!their!dispersion!pattern!!***********************************************************************************!The!following!three!questions!are!linked:!!In!the!1600's!and!1700's,!sailors!inherently!understood!the!power!of!exponential!population!growth.!!They!would!take!live!animals!with!them!on!their!ships!to!be!released!onto!vegetation!covered!islands!(lacking!predators!or!competitors).!!They!knew!when!they!returned!later,!the!animals!would!have!proliferated!exponentially!and!they!would!then!have!a!ready!food!source!when!they!returned.!!The!preferred!animal!to!release!was!goats!because!they!eat!just!about!any!vegetation!and!are!quite!good!at!surviving!(remnant!goat!populations!can!be!found!on!oceanic!islands!around!the!world!today!as!a!result!).!!One!clever!ship's!captain!thought!they!could!do!much!better!than!goats!by!releasing!rabbits,!which!have!a!much!shorter!generation!time.!!Ten!rabbits!were!released!onto!a!small!island!off!the!coast!of!California!in!the!year!1725.!!The!captain!computed!that!the!birth!rate!of!rabbits!was!8,!while!the!death!rate!was!0.5.!!!!5.!!What!is!the!intrinsic!rate!of!increase!of!the!rabbit!population?!!A.!!0.5!B.!!5!C.##7.5#D.!8!E.!75!! !

!6.!!The!ship!that!had!released!the!rabbits!proceeded!across!the!Pacific!Ocean,!trading!for!goods!in!Japan,!China,!and!Indonesia,!stopping!off!in!Hawaii!on!the!way!back!to!the!California!Coast,!which!they!reached!exactly!2!years!later!in!1727.!!By!that!time,!the!ship's!captain!was!anxious!to!see!how!his!little!experiment!had!paid!off.!!If!the!rabbit!population!had!grown!exponentially!while!they!were!away,!how!many!rabbits!could!he!expect!to!find?!!A.!150!B.!316,228!C.!3,269,017!D.#32,690,174#E.!7.52!!7.!!The!captain!had!learned!while!in!Japan!that!rabbit!fur!could!fetch!a!nice!price,!so!as!the!ship!approached!the!islands,!visions!of!chests!filled!overflowing!with!gold!coins!and!treasure!filled!his!head.!!The!captain!and!crew!were!royally!disappointed!by!what!they!found!when!they!landed.!!The!island!was!barely!recognizable,!with!scattered!bits!of!thorny!vegetation!left!from!what!had!been!a!lush,!vegetation!covered!island.!!Worse!still,!there!were!only!a!few!dozen!rabbits!hopping!around,!looking!near!death.!!What!is!the!most!likely!explanation!for!what!they!saw?!!A.!the!birth!rate!dropped!because!the!plants!on!the!island!were!inedible!B.!the!death!rate!increased!because!a!predator!found!the!rabbit!population!!C.!another!ship!found!the!rabbit!population!and!harvested!it!D.#the#rabbits#initially#grew#exponentially,#but#overbrowsed#the#vegetation#and#the#population#crashed#E.!!the!habitat!was!unsuitable!for!rabbits,!so!they!never!proliferated!as!expected!!*****************************end!of!linked!questions*****************************!! !

!8.!!Sara!Souther,!a!recent!biology!PhD!student,!measured!λ,!the!finite!rate!of!increase,!for!ginseng!populations!over!several!years.!!Each!year,!she!also!measured!the!deviation!of!average!maximum!daily!temperatures!from!the!long6term!mean!for!the!site,!resulting!in!the!figure!below.!!What!do!the!data!tell!us!about!the!potential!effect!of!future!global!warming!on!population!growth!rate?!(the!x6axis!is!temperature!deviation!from!the!long6term!average,!expressed!as!standard!deviations)!!

!!A.!The!populations!will!grow!for!the!foreseeable!future!B.!All!populations!are!in!decline,!regardless!of!temperature!C.!Temperature!increases!will!improve!the!population!growth!rate!D.#Temperature#increases#will#cause#a#decrease#in#the#population#growth#rate#E.!Temperature!causes!a!linear!change!in!population!growth!rate!!9.!!In!the!U.S.,!several!trends!can!be!noted!in!the!news;!(1)!a!special!segment!in!the!New!York!Times!dedicated!to!a!single!age!group,!(2)!an!increasing!number!of!articles!on!retirement!and!how!Americans!are!not!saving!enough,!(3)!increasing!articles!about!fitness!aimed!at!men!and!women!in!their!50's!and!60's.!!What!'ultimately'!explains!this!trend?!!A.##Separation#of#men#and#women#in#World#War#II#followed#by#a#baby#boom##B.!!A!proven!trend!that!wealth!and!health!are!closely!related!C.!!The!effects!of!the!recent!'Great!Recession'!D.!!These!are!just!societal!offshoots!of!our!highly!divided!political!system!E.!!They!are!unrelated!trends!! !

!"

0.7

1.0

1.3

-2 -1 0 1 2

Temperature (SD)

(b)

Line of best fit ------- ! = 1 y = -0.0528x2 - 0.0100x + 1.0145

!10.!!You!are!told!that!Germany!has!a!λ=0.998.!!What!can!we!discern!from!this?!!A.!If!Germany!is!at!S.A.D.,!then!Nt+1=0.998Nt!B.!If!Germany!is!at!S.A.D.,!the!population!of!Germany!is!declining!by!0.2%/y!C.!The!eigenvalue!of!the!age6specific!population!projection!matrix!for!Germany!is!0.998!D.##All#of#the#above#are#true#E.!!None!of!the!above!are!true!!###################the!following!5!questions!are!linked##############!

!"Sugar!beet,!sugar!beet,!sugar!beet"…this!is!the!song!of!the!male!Carolina!Wren!in!springtime.!!This!fierce!little!songbird!is!defending!its!territory!and!building!a!nest!to!raise!a!family.!!The!following!is!a!partial!life!table!for!this!diminutive!bird:!!Age!(x)!!!!! sx! lx! bx! Fx!0! ! .4! 1! 0! 0!1! ! .5! 0.4! 2! 0.8!2! ! .5! 0.2! 5! 2.5!3! ! 0! 0.1! 0! 0!!11.!!What!is!the!probability!that!a!newborn!Carolina!Wren!will!survive!to!age!2?!!A.!0.1!B.#0.2#C.!0.4!D.!0.5!E.!1!!12.!!What!is!the!expected!lifetime!offspring!production!of!a!newborn!Carolina!Wren!with!the!life!history!parameters!shown?!!A.#1.8#B.!3.3!C.!7!D.!0.8!E.!impossible!to!calculate!given!the!data!! !

!13.!!What!is!the!life!expectancy!of!a!one!year!old!Carolina!Wren?!!A.!0.5!B.!1!C.!1.2!D.#1.25#E.!2!!14.!!What!Type!of!survivorship!curve!does!a!Carolina!Wren!exhibit?!!A.!Approximately!Deevey!Type!I!B.#Approximately#Deevey#Type#II#C.!Approximately!Deevey!Type!III!D.!Approximately!Deevey!Type!IV!!!15.!!If!a!population!of!Carolina!wrens!has!N0!=!0,!N1=10,!N2=16,!N3=0!at!time!t,!what!will!the!total!N!be!at!time!t+1?!!A.!!13!B.!!26!C.!!48!D.##61#E.!!124!################end!of!linked!questions#####################!!666666666666666666666666666666666666663!linked!questions6666666666666666666666666666666666!Blennerhassett!Island!is!a!historical!state!park!on!an!island!in!the!Ohio!River!near!Parkersburg,!WV.!!As!in!most!WV!state!parks,!there!is!a!severe!deer!overpopulation!at!the!park!and!prior!to!controlled!hunts!starting!in!2001,!the!population!was!about!at!its!maximum!sustainable!level!of!500!on!the!206!hectare!island!(about!1!deer!per!acre!).!!The!maximum!intrinsic!rate!of!increase!for!deer!has!been!estimated!at!0.5.!!No!predators!exist!on!the!island!and!within6species!competition!is!assumed!to!be!the!only!force!acting!to!keep!population!growth!in!check.!!The!following!questions!are!based!on!the!above!information.!!16.!!What!is!the!most!likely!cause!of!density6dependent!population!regulation!of!the!deer!on!Blennerhassett?!!A.##Direct#effects#of#resource#depletion#B.!!Higher!predation!hazard!on!young!due!to!greater!foraging!required!by!parent!deer!C.!!Increased!predation!rate!as!predators!'key!in'!on!abundant!deer!D.!The!Allee!effect!E.!!Enlightened!management!keeping!the!deer!N!at!precisely!K/2.!

!17.!!With!the!density6dependent!population!growth!described,!what!is!the!slope!of!the!'parsimonious'!plot!of!r!(y6axis)!vs.!N!(x6axis)?!!A.##2.001#B.!6.01!C.!0!D.!.01!E.!.001!!18.!!If!another!(deerless)!island!in!the!Ohio!River!was!half!the!size!of!Blennerhassett,!but!otherwise!ecologically!similar,!and!a!small!herd!of!5!deer!swam!to!that!island!to!'found’!a!new!population,!how!many!years!(rounded!to!the!nearest!year)!would!it!take!for!that!island's!deer!population!to!reach!half!its!carrying!capacity?!!A.!!1!year!B.!!3!years!C.!!6!years!D.##8#years#E.!!!10!years!!66666666666666666666666666666666666666666666end!of!linked!questions6666666666666666666666666666666!!19.!!Plants!and!fish!have!density6dependence!that!differs!from!organisms!with!less!'plastic'!body!sizes!in!that:!!A.!!there!is!usually!an!Allee!effect!in!plants!B.##densities#in#size2plastic#species#actually#decline#with##time#after#some#max#N#C.!!numbers!continue!to!increase!seemingly!without!limits!in!such!plastic!species!D.!!plants!and!fish!do!not!deplete!resources!in!competition!within!populations!E.!!the!rule!governing!density6dependence!in!plants!and!fish!is!less!parsimonious!! !

!20.!!Dr.!McGraw!saw!this!interesting!interaction!between!a!magpie!and!a!bison!in!Yellowstone!Park!over!spring!break.!!The!magpie!was!observed!eating!blood6sucking!insects!on!the!bison's!skin.!!What!kind!of!relationship!can!you!infer!the!bison!and!magpie!most!likely!have!based!on!this!observation?!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !A.!competition!B.!predator6prey!C.!amensalism!D.!commensalism!E.#mutualism#!(((((((((((((((((((((((((((((((The!following!4!questions!are!linked)))))))))))))))))))!!Grizzly!bears!and!black!bears!are!surprisingly!similar!in!their!diets!and!in!NW!Montana!they!live!in!the!same!geographic!regions!(Aune!1994).!!They!do!partition!the!environment!spatially!within!regions!to!a!degree!(black!bears!prefer!forests!a!bit!more;!grizzlies!prefer!open!and!higher!elevation!areas!a!bit!more)!and!temporally,!feeding!at!different!times!of!day,!for!example.!!!!21.!!The!larger,!more!aggressive!grizzly!bear!has!been!known!to!occasionally!kill!black!bears,!though!this!is!rare.!!Given!all!of!the!above!information,!what!is!likely!true!about!the!black!bear!6grizzly!bear!competitive!relationship?!!A.!!They!compete!via!exploitation!competition!B.!!They!compete!via!interference!competition!C.##They#compete#via#both#exploitation#and#interference#competition#D.!!They!do!not!compete!with!each!other!through!niche!differentiation!E.!!!They!do!not!compete;!it!is!a!predator6prey!relationship!primarily!! !

!22.!!If!K!for!the!grizzly!bear!(species!1)!is!100,!and!K!for!the!black!bear!is!120!in!a!mountain!range!of!northwestern!Montana,!and!the!competitive!effect!of!black!bears!on!grizzlies!is!0.8,!while!the!competitive!effect!of!grizzlies!on!black!bears!is!0.9,!what!is!the!predicted!outcome!of!competition,!assuming!Ninitial!>0!for!both!species?!!A.!The!grizzly!bear!wins!B.!The!black!bear!wins!C.#The#two#species#will#coexist#D.!The!outcome!will!depend!on!initial!N!E.!The!outcome!cannot!be!predicted!with!the!information!given!!23.!!If!a!disease!entered!the!black!bear!population!and!wiped!them!out,!what!would!the!grizzly!population!size!eventually!become!after!a!long!time?!!A.!0!B.#100#C.!120!D.!125!E.!133!!24.!!If!the!black!bear!population!was!wiped!out!(as!in!the!question!above),!what!could!happen!evolutionarily!to!grizzly!bears!due!to!the!reduction!of!competition?!!A.!character!displacement!B.!!evolution!of!a!larger!mean!size!for!the!grizzly!bear!C.#evolution#of#a#smaller#mean#size#for#the#grizzly#bear#D.!grizzly!bears!would!evolve!greater!aggressiveness!E.!nothing!would!happen!evolutionarily!due!to!the!reduction!in!competition!!(((((((((((((((((((((((((((((((((((end!of!4!questions)))))))))))))))))))))))))))))))!!25.!!Of!the!two6species!relationships!that!describe!'Consumers',!one!of!them!is!distinct!from!the!others!because!it!is!actually!'+,!0'!(or!perhaps!even!+,!+)!rather!than!+,!6.!!Which!relationship!is!different!in!this!way?!!A.!predator6prey!B.!parasite6host!C.!parasitoid6host!D.!herbivore6plant!E.#detritivore2detritus#! !

!26.!!When!we!developed!the!Volterra!Predator6Prey!equations,!at!the!outset!we!started!with:!!A.#the#exponential#growth#equations#B.!the!logistic!equations!C.!the!Lotka6Volterra!equation!D.!the!age6specific!population!growth!equations!E.!a!new!equation!entirely!!27.!!The!response!of!the!predation!rate!to!prey!population!size!is!called:!!A.!!the!physiological!response!B.##the#functional#response#C.!!the!numerical!response!D.!the!behavioral!response!E.!the!asymptotic!response!!^^^^^^^^^^^^^^^^^^The!following!3!questions!are!linked^^^^^^^^^^^^^^!The!praying!mantis6aphid!predator6prey!system!can!provide!a!nice!clean!study!system!in!a!well6defined!crop!field.!!Let!us!assume!their!interaction!follows!Volterra!Predator6Prey!dynamics.!!!!28.!!If!!N2!is!100!when!the!aphid!population!is!not!growing,!and!the!mantis!catches!1%!of!the!prey!per!unit!time,!what!is!the!intrinsic!rate!of!increase!of!the!aphid!population?!!A.!!0.01!B.!!0.1!C.#1#D.!10!E.!!cannot!be!determined!from!the!information!given!!29.!If!N1!is!1,000,000!when!dN2/dt!=!0,!and!the!conversion!efficiency!of!caught!aphids!to!baby!praying!mantis!is!0.0001,!then!what!is!the!death!rate!of!the!praying!mantis?!!A.!0.01!B.!0.1!C.#1#D.!10!E.!cannot!be!determined!with!the!information!given!! !

!30.!!If!there!are!2,456,198!aphids!and!216!praying!mantises!in!a!field!following!the!above6described!Volterra!predator6prey!dynamics,!what!is!true!about!the!two6species!population!growth!rates?!!A.!!dN1/dt=!+,!dN2/dt!=!+!B.#dN1/dt=#2,#dN2/dt#=#+#C.!dN1/dt=!+,!dN2/dt!=!6!D.!dN1/dt=!6,!dN2/dt!=!6!E.!dN1/dt=!0,!dN2/dt!=!+!!^^^^^^^^^^^^^^^^^^^^^end!of!linked!questions^^^^^^^^^^^^^^^^^^^^!!

!!!!BONUS!!31.!!Aphids,!by!sucking!the!sap!from!stems!of!crops,!reduce!yield.!!Two!neighboring!farmers!have!two!equal!size!fields!with!equally!bad!infestations!of!aphids!in!both.!!Farmer!1!sprays!his!fields!with!insecticide!to!kill!the!aphids,!while!Farmer!2!does!not.!!At!the!end!of!the!year!they!compare!notes.!!Farmer!2!is!feeling!rather!smug!after!this!encounter!because!not!only!did!she!pay!nothing!for!insecticide,!but!her!crop!had!a!slightly!HIGHER!yield!than!Farmer!1.!!What!explains!this!result?!!A.!!Character!displacement!B.!!The!Allee!effect!C.##The#Volterra#Principle#D.!!r6selection!E.!!K6selection!!!!!!