29-023 mutualism-altruism - John Burroughs Schoolscience.jburroughs.org/sdeken/sdeken/advbio/abnotes/2012spring4/mutualismaltruism.pdfFacultave Altruism Facultave Altruism Show Nature

4/25/12

1

DominanceHierarchyDespo0c(a.k.a.steep)

Macaques

AlphaBeta

Gamma

Linear(a.k.a.shalloworegalitarian)

Wolves

HelpingBehavior ObligatealtruismReciprocity

Faculta0vealtruism

MutualismSharedgainofdirectfitness

Example:Preycapturebylionpride

Delayedgainofdirectfitness(dependentuponrepayment)Example:Vampirebatbloodexchanges

Permanentlossofdirectfitness(withpotenLalforindirect

fitnessgain)Example:Honeybeeworkers

foragingforcolony

Temporarylossofdirectfitness(withpotenLalforindirectfitnessgain

followedbypersonalreproducLon)Example:Floridascrubjayhelpingatthenest,thengainingparentalterritory

The direct reproductive success of individuals that engage in different kinds of social interactions

Effect on direct reproductive success of Type of interaction Social Donor Social Recipient Mutualism + + Reciprocity + (delayed) + Altruism - + Selfish Behavior + - Spiteful Behavior - -

Mutualism

Mutualism

ShowPlanetEarth:GreatPlainsLions(35:45‐43:33)or(YouTube)

AfricanWildDogs(YouTube)

Mutualism

4/25/12

2

Reciprocity‐ThePrisonersDilemma Reciprocity‐ThePrisonersDilemma

SayPlayer1DEFECTS(doesnotcooperatewiththeirpartner)andPlayer2COOPERATES(cooperateswiththeirpartner),Player1gets5points(noprisonLme)andPlayer2gets0points(5yearsofprisonLme).SayPlayer1andPlayer2bothCOOPERATE(witheachother),theneachgets3points(2yearsofprisonLme).SayPlayer1andPlayer2bothDEFECT(eachratouttheother),theeachgets1point(4yearsofprisonLme).

Dilbert&ThePrisoner’sDilemma

ReciprocityReciprocity

MarcHauser

ShowTrialsofLife:Friends&Rivals

Baboons(YouTube)

VampireBats(RawNature&YouTube)

ReciprocityFaculta0veAltruism

ShowTrialsofLife:GrowingUpScrubJays

4/25/12

3

Faculta0veAltruism Faculta0veAltruism

ShowNatureLivingTogetherSocialBehaviorKinSelecLon

BrownBabblers

ObligateAltruism(a.k.a.EusocialBehavior)ShowNatureLivingTogetherSocialBehaviorKinSelecLon

NakedMoleRats

SnappingShrimp(YouTube)

EusocialAnimals

3MainTraitsforEusocialAnimals

Othertraits...

4/25/12

4

KinSelec0on

CoefficientofRelatedness(r)

r=.5n

EusocialAnimals

ShowNatureLivingTogetherSocialBehavior&KinSelecLon

Bees&Hamilton

William D. Hamilton

WorkerHoneybees‐theul0mateineusocialbehavior

Haplodiploidreproduc0on‐Hymenoptera Coefficientofrelatedness:Whatpropor0onofgenesaresharedbytwoindividuals?

SIMPLE!FindthenumberofconnecLonsbetweenoneindividualbacktoasharedancestorandthenthenumberofconnecLonstothesecondindividual.RAISE1/2tothepowerofthenumberofconnecLons.DOTHISseparatelyforEACHsharedancestorandthenaddtheprobabiliLestogether.

FOREXAMPLE:#forhalfsibstherearetwoconnecLons[andonlyonesharedancestor]‐‐soraise1/2tothepoweroftwo[1/2squared=1/4;25%related)#forfullsibseachhastwoconnecLons[BUTtheyshareTWOancestors:momANDdad]soraise1/2tothepoweroftwoformomandthenagainfordad[1/2squared=1/4,thenagain;thetwoancestorsresultin1/4+1/4=1/2:50%related]#forfirstcousins‐‐eachhasFOURconnecLons‐‐soraise1/2tothepowerofFOUR4(=1/16);thenagain=1/16;addedtogether=1/8

4/25/12

5

A B2

DC

r=0.52rbetweenC&D=0.25

HalfSiblingCoefficientofRelatedness #forhalfsibstherearetwoconnecLons[andonlyonesharedancestor]‐‐soraise1/2tothepoweroftwo[1/2squared=1/4;25%related)

B1

1

2

r=0.52+0.52rbetweenC&D=0.5

FullSiblingCoefficientofRelatedness

#forfullsibseachhastwoconnecLons[BUTtheyshareTWOancestors:momANDdad]soraise1/2tothepoweroftwoformomandthenagainfordad[1/2squared=1/4,thenagain;thetwoancestorsresultin1/4+1/4=1/2:50%related]

A B

DC

1

2

1

2

r=0.54+0.54rbetweenC&D=0.125

CousinCoefficientofRelatedness

#forfirstcousins‐‐eachhasFOURconnecLons‐‐soraise1/2tothepowerofFOUR4(=1/16);thenagain=1/16;addedtogether=1/8

A B

DC

1

2

1

2

FE

3 3

4 4

Haplodiploidreproduc0on‐Hymenoptera

r=0.5+0.52rbetweenC&D=0.75

HaplodiploidCoefficientofRelatednessofSisters

Sincedroneshaveonlyonesetofchromosomestheymustallbesharedbythesisters!SonowtheequaLonchanges!Thereisa100%chancethesisterssharetheirfathersgenesnotjusta50%chancelikethatindiploidspecies!

A B

DC

1

2

r=1rbetweenD&A=1

HaplodiploidCoefficientofRelatednessofDaughters&Dronedad

A B

D

1

C

4/25/12

6

r=0.51rbetweenD&A=0.5

HaplodiploidCoefficientofRelatednessofDaughters&Queen(mom)

A B

D

1

C

r=0.52rbetweenC&D=0.25

HaplodiploidCoefficientofRelatednessofBrothers&Sisters

A B

D

1

2

C

Ishaplodiploidynecessarytobeeusocial?

Ishaplodiploidysufficienttobeeusocial?