evolutionary dynamics study how populations of reproducing individuals change over time. prelife
DESCRIPTION
Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife Protocells Viruses Cells Cancer cells Multi-cellular organisms Insect societies People – genetic or cultural reproduction Evolution by learning, imitation, communication. Time line - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/1.jpg)
Evolutionary Dynamics
Study how populations of reproducing individuals change over time.
PrelifeProtocellsVirusesCellsCancer cellsMulti-cellular organismsInsect societiesPeople – genetic or cultural reproductionEvolution by learning, imitation, communication
![Page 2: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/2.jpg)
Time line
13700 Universe 4567 Sun
3500 chemical evidence of life on Earth 2100 bacterial fossils (simple multi-cellular) 1800 eucaria 600 complex multi-cellularity 120 insect societies 1 human language
million years ago
cooperation is needed for construction
![Page 3: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/3.jpg)
What makes evolution constructive?
Why is evolution “open ended”?
What is the difference between genetic and cultural evolution?
Evolution is a search process. What generates the space that is being searched?
Is i-life stable?
![Page 4: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/4.jpg)
Can you eradicate HIV infection?
Can you cure cancer with the simultaneous use of 2 or more targeted drugs?
Can you make people cooperate with the next generation (and thereby save the world)?
![Page 5: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/5.jpg)
What is it that evolves?
![Page 6: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/6.jpg)
What is it that evolves?
Populations of reproducing individuals
![Page 7: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/7.jpg)
Mutation
![Page 8: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/8.jpg)
Selection
Time
![Page 9: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/9.jpg)
Cooperation
Time
![Page 10: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/10.jpg)
Evolution of cooperation
Martin Nowak, Harvard University
![Page 11: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/11.jpg)
What is cooperation?
Donorpays a cost, c
Recipientgets a benefit, b
Cost and benefit are measured in terms of fitness.Reproduction can be genetic or cultural.
![Page 12: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/12.jpg)
I cooperate I defect
you cooperate b - c - c
you defect b 0
you get
Prisoner’s Dilemma
b > c > 0
![Page 13: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/13.jpg)
What is the dilemma ?
Two rational players defect and end up with a low payoff, 0.
Two irrational players might cooperate and receive a higher payoff, b – c .
![Page 14: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/14.jpg)
Natural selection chooses defection
D
CC C
C
CC
DD
DD
D
D
D
D
In any mixed population, defectors have a higher payoff than cooperators.
![Page 15: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/15.jpg)
Natural selection needs help to favorcooperators over defectors.
![Page 16: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/16.jpg)
Five mechanisms for the evolution of cooperation:
Direct reciprocityIndirect reciprocitySpatial selectionGroup selectionKin selection
![Page 17: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/17.jpg)
Direct reciprocity
‘I help you, you help me.’
![Page 18: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/18.jpg)
Repeated Prisoner’s Dilemma
Player 1 : C D C D C C C ….
Player 2 : D C D D C C C ….
The Folk theorem
![Page 19: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/19.jpg)
Repeated Prisoner’s Dilemma
Player 1 : C D C D C C C ….
Player 2 : D C D D C C C ….
What is a good strategy for playing this game?
Robert Axelrod
![Page 20: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/20.jpg)
Tit-for-tat
• I start with cooperation.
• If you cooperate, then I will cooperate.
• If you defect, then I will defect.
Anatol Rapaport
![Page 21: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/21.jpg)
Tit-for-tat is unforgiving
Errors destroy cooperation
Tit-for-tat : CCCCDCDCDCDDDDDD….
Tit-for-tat : CCCDCDCDCDDDDDDD….
![Page 22: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/22.jpg)
Let natural selection design a strategy
Random
![Page 23: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/23.jpg)
Always defect
Random
Let natural selection design a strategy
![Page 24: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/24.jpg)
Let natural selection design a strategy
Tit-for-tat
Always defect
Random
![Page 25: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/25.jpg)
Let natural selection design a strategy
Tit-for-tat Generous Tit-for-tat
Always defect
Random
![Page 26: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/26.jpg)
Generous Tit-for-tat
• I start with cooperation.• If you cooperate, then I will cooperate.• If you defect, then I will cooperate with a certain probability (q = 1- c / b).
Evolution of forgiveness
![Page 27: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/27.jpg)
Let natural selection design a strategy
Tit-for-tat Generous Tit-for-tat
Always defect
Random
![Page 28: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/28.jpg)
Let natural selection design a strategy
Tit-for-tat Generous Tit-for-tat
Always defect Always cooperate
Random
![Page 29: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/29.jpg)
Let natural selection design a strategy
Tit-for-tat Generous Tit-for-tat
Always defect Always cooperate
War and peace
![Page 30: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/30.jpg)
Let natural selection design a strategy
Tit-for-tat Generous Tit-for-tat
Always defect Always cooperate
Win-stay, lose-shift
![Page 31: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/31.jpg)
Win-stay, lose-shift
• If I am doing well (payoff b or b-c) then I will repeat my move.
• If I am doing badly (payoff 0 or -c) then I will change my move.
If b/c<2 then a stochastic variant of WSLS does well(where you return to C after DD only with a certain probability).
![Page 32: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/32.jpg)
Direct reciprocity
… allows the evolution of cooperation if
w > c / b
b…benefitc…costw…probability of another round
![Page 33: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/33.jpg)
Indirect reciprocity
‘I help you.
Somebody helps me.’
![Page 34: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/34.jpg)
Indirect reciprocity works via reputation
A B A B
A does not help B
The reputation of A increases. The reputation of A decreases.
A helps B
donor recipient donor’s reputation
cooperate -c +b +1
defect 0 0 -1
Nowak & Sigmund, Nature 1998
![Page 35: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/35.jpg)
People help those who help others.
Helpful people have a higher payoff in the end.
Experimental confirmation:
Wedekind & Milinski, Science 2000
![Page 36: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/36.jpg)
A B
A helps B
Observers
Rest of the population
gossip
Rep
utatio
n o
f A is u
pd
ated.
Gossip spreads reputation
![Page 37: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/37.jpg)
Games of indirect reciprocity are cognitivelydemanding; individuals need to monitor the social network of a group. => evolution of social intelligence
Individuals must be able to talk to each other about others.=> evolution of human language
![Page 38: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/38.jpg)
David Haig:
“For direct reciprocity you need a face.
For indirect reciprocity you need a name.”
![Page 39: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/39.jpg)
A rule for indirect reciprocity
q > c / b
q … probability to know someone’s reputation c … cost of cooperation b … benefit of cooperation
![Page 40: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/40.jpg)
Spatial selection
Spatial games
Games on graphs
Games in phenotype space
Games on sets
![Page 41: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/41.jpg)
Spatial games
CooperatorsDefectors
Nowak & May, Nature 1992
![Page 42: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/42.jpg)
Games on graphs
CooperatorsDefectorsCC
C
C
C
DD D
D
D
The graph describes a spatial structureor a social network.
‘Evolutionary graph theory’ (Lieberman et al, Nature 2005)
![Page 43: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/43.jpg)
CC
C
C
C
DD D
D
D
2b-5cb
2b-3c
2b-2c
b
b
b
Cooperators pay a cost c for each neighbor to receive benefit b.
![Page 44: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/44.jpg)
Spatial selection on graphs favors cooperation if
b / c > kk…(average) number of neighbors
weak selection
Ohtsuki et al, Nature 2006
![Page 45: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/45.jpg)
Evolutionary set theory
People belong to sets.
People interact with others in the same sets.
People adopt strategy and set membership of successful individuals.
Tarnita et al, PNAS 2009
![Page 46: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/46.jpg)
‘There can be no doubt that a tribe including many members who [...] are always ready to give aid to each other and to sacrifice themselves for the common good, would be victorious over other tribes; and this wouldbe natural selection.’
Charles Darwin, The Descent of Man, 1871
Group selection
![Page 47: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/47.jpg)
Group selection
C C
CDD
D
D
D
Play the game with others in your group.
Offspring are added to the group.
Groups divide when reachinga certain size.
Groups die.
CCD
C CC
![Page 48: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/48.jpg)
Group selection
favors cooperators if
b / c > 1 + n / m
n … group sizem … number of groups
Traulsen & Nowak, PNAS 2006
![Page 49: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/49.jpg)
Kin selection
‘I will jump into the river to save
2 brothers or 8 cousins’
J.B.S Haldane
The interaction occurs between genetic relatives.
![Page 50: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/50.jpg)
Hamilton’s rule
r > c / b
r … coefficient of relatedness c … cost of cooperation b … benefit of cooperation
Inclusive fitness theory
![Page 51: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/51.jpg)
Inclusive fitnessis a limited concept.
Inclusive fitness is not needed toexplain eusociality other aspectsof social evolution.
Hamilton’s rule almost never holds.
Once fitness is calculated everyeffect of relatedness is included.
Nowak, Tarnita, Wilson, “The evolution of eusociality”, Nature 2010
![Page 52: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/52.jpg)
What is inclusive fitness?
Hamilton: “Inclusive fitness may be imagined as the personal fitness which an individual actually expresses in its production of adult offspring as it becomes after it has been first stripped and then augmented in a certain way. It is stripped of all components which can be considered as due to the individual's social environment, leaving the fitness which he would express if not exposed to any of the harms or benefits of that environment. This quantity is then augmented by certain fractions of the quantities of harm and benefit which the individual himself causes to the fitnesses of his neighbours.
![Page 53: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/53.jpg)
Fitness Inclusive fitness
interaction => payoff=> fitness=> reproduction
only one actor is considered
IF = the effect of this actionon his own payoff + the effect of this actions on thepayoff of others x relatedness
![Page 54: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/54.jpg)
fitness fitnesssubdivided intoadditive components
![Page 55: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/55.jpg)
The two methods are not equivalent.
In general it is not possible to decompose fitnessinto additive components caused by individual actions.
![Page 56: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/56.jpg)
Five mechanisms for cooperation
Direct reciprocity : I help you, you help me.
Indirect reciprocity : I help you, somebody helps me.
Spatial selection : Neighbors help each other.
Group selection : groups of cooperators out-compete
Kin selection : cooperate with genetic relatives.
other groups.
![Page 57: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/57.jpg)
Cooperators
• Erez Lieberman (Houston)• Robert May (Oxford)• Johanna Mollerstrom (Harvard)• Hisashi Ohtsuki (Tokyo)• Jason Olejarz (Harvard)• Alexander Peysakhovich (Harvard)• David Rand (Yale)• Johannes Reiter (IST)• Karl Sigmund (Vienna)• Corina Tarnita (Princeton)• Christine Taylor (Princeton)• Arne Traulsen (Ploen)• Matthijs van Veelen (Amsterdam)• Caller Veller (Harvard)• Erez Yoeli (Harvard)
• Ben Adlam (Harvard)• Ben Allen (Harvard)• Tibor Antal (Edinburgh)• Ivana Bozic (Harvard)• Krishnendu Chatterjee (IST)• Anna Dreber (Stockholm)• Feng Fu (Zurich)• Drew Fudenberg (Harvard)• Montasser Ghachem (Harvard)• Whan Ghang (Harvard)• Christoph Hauert (UBC)• Oliver Hauser (Harvard)• Christian Hilbe (Harvard)• Alison Hill (Harvard)• Moshe Hoffman (Harvard)• Lorens Imhof (Bonn)• Scott Kominers (Harvard)
![Page 58: Evolutionary Dynamics Study how populations of reproducing individuals change over time. Prelife](https://reader036.vdocuments.net/reader036/viewer/2022062720/568134b1550346895d9bcdcb/html5/thumbnails/58.jpg)